text
stringlengths 66
4.65k
|
|---|
English: The goal of this paper is to provide a survey and application-focused atlas
of collective behavior coordination algorithms for multi-agent systems.
We survey the general family of collective behavior algorithms for
multi-agent systems and classify them according to their underlying
mathematical structure. In doing so, we aim to capture fundamental mathematical
properties of algorithms (e.g., scalability with respect to the number of
agents and bandwidth use) and to show how the same algorithm or family of
algorithms can be used for multiple tasks and applications.
Collectively, this paper provides an application-focused atlas of algorithms
for collective behavior of multi-agent systems, with three objectives:
1. to act as a tutorial guide to practitioners in the selection of
coordination algorithms for a given application;
2. to highlight how mathematically similar algorithms can be used for a
variety of tasks, ranging from low-level control to high-level coordination;
3. to explore the state-of-the-art in the field of control of multi-agent
systems and identify areas for future research.
Chinese: 本文旨在提供一份面向应用的多智能体系统集体行为协调算法综述图谱。
我们综述了多智能体系统集体行为算法的总体类别，并按照其底层数学结构进行分类。
通过这种方式，我们旨在捕捉算法的基本数学特性（例如，可扩展性与智能体数量和带宽使用的关系），并展示同一算法或算法家族如何应用于多种任务和应用。
总体而言，本文提供了一本面向应用的多智能体系统集体行为算法图谱，具有三个目标：
1. 作为实践者在选择特定应用协调算法时的教程指南；
2. 突出数学相似的算法如何应用于从低级控制到高级协调的各种任务；
3. 探索多智能体系统控制领域的前沿技术，并确定未来研究方向。
|
English: Room acoustic simulations at low frequencies often face significant
uncertainties of material parameters and boundary conditions due to absorbing
material. We discuss the application of Physics-Informed Neural Networks
(PINNs) to solve the (forward) Helmholtz equation in three dimensions (3D),
employing mini-batch stochastic gradient descent with periodic resampling every
100 iterations for memory-efficient training. Addressing the computational
challenges posed by the extension of PINNs from 2D to 3D for acoustics, DeepXDE
is used for implementing the forward PINN. The proposed numerical method is
benchmarked against an analytical solution of a standing wave field in 3D. The
PINN results are also compared to the Finite Element Method (FEM) solutions for
a 3D wave field computed with openCFS. The alignment between PINN-generated
solutions and analytical/FEM solutions shows the feasibility of PINNs modeling
3D acoustic applications for future inverse problems, and validating the
accuracy and reliability of the proposed approach. Compared to FEM,
establishing the PINN model took few hours (similar to the setup of a FEM
simulation), the training took 38h to 42.8h (which is longer than the solution
of the FEM simulation, which took 17min-19min), and the inference took 0.05
seconds being more than 20,000 times faster than the FEM benchmark openCFS
using the same number of degrees of freedomwhen producing the results. Thereby,
the insight is gained that 3D acoustic wave simulations in the frequency domain
are feasible for forward PINNs and can predict complex wave behaviors in
real-world applications.
Chinese: 低频房间声学模拟由于吸声材料，在材料参数和边界条件方面经常面临显著的不确定性。我们讨论了物理信息神经网络（PINNs）在求解三维（3D）的（正向）亥姆霍兹方程中的应用，采用每100次迭代进行周期性重采样的小批量随机梯度下降进行内存高效的训练。针对PINNs从二维扩展到三维以解决声学问题所提出的计算挑战，使用DeepXDE实现正向PINN。所提出的数值方法与三维驻波场的解析解进行了基准测试。PINN结果也与使用openCFS计算的三维波场的有限元法（FEM）解进行了比较。PINN生成的解与解析解/FEM解的一致性表明了PINNs建模三维声学应用以用于未来逆问题的可行性，并验证了所提出方法的准确性和可靠性。与FEM相比，建立PINN模型仅用了几小时（类似于FEM模拟的设置时间），训练用了38小时到42.8小时（比FEM模拟的求解时间17分钟到19分钟要长），而推理只需0.05秒，在产生结果时比使用相同自由度的FEM基准openCFS快20,000多倍。由此得出结论，频域中的三维声波模拟对于正向PINNs是可行的，并且可以预测实际应用中的复杂波行为。
|
English: We introduce an infinite-horizon, continuous-time portfolio selection problem
faced by an agent with periodic S-shaped preference and present bias. The
inclusion of a quasi-hyperbolic discount function leads to time-inconsistency
and we characterize the optimal portfolio for a pre-committing, naive and
sophisticated agent respectively. In the more theoretically challenging problem
with a sophisticated agent, the time-consistent planning strategy can be
formulated as an equilibrium to a static mean field game. Interestingly,
present bias and naivety do not necessarily result in less desirable risk
taking behaviors, while agent's sophistication may lead to excessive leverage
(underinvestement) in the bad (good) states of the world.
Chinese: 我们介绍了一个无限远期、连续时间的投资组合选择问题，该问题涉及一个具有周期性S形偏好和当前偏好的代理人。包含准双曲贴现函数会导致时间不一致性，我们分别对预先承诺的、天真的和复杂的代理人进行了最优投资组合的刻画。在更具有理论挑战性的复杂代理人问题中，时间一致的计划策略可以表述为静态平均场游戏的均衡。有趣的是，当前偏见和天真并不一定导致更不可取的风险承担行为，而代理人的复杂性可能导致在坏（好）状态下过度杠杆（投资不足）。
|
English: Entanglement witnesses (EWs) constitute one of the most important
entanglement detectors in quantum systems. Nevertheless, their complete
characterization, in particular with respect to the notion of optimality, is
still missing, even in the decomposable case. Here we show that for any
qubit-qunit decomposable EW (DEW) W the three statements are equivalent: (i)
the set of product vectors obeying \bra{e,f}W\ket{e,f}=0 spans the
corresponding Hilbert space, (ii) W is optimal, (iii) W=Q^{\Gamma} with Q
denoting a positive operator supported on a completely entangled subspace (CES)
and \Gamma standing for the partial transposition. While, implications
$(i)\Rightarrow(ii)$ and $(ii)\Rightarrow(iii)$ are known, here we prove that
(iii) implies (i). This is a consequence of a more general fact saying that
product vectors orthogonal to any CES in C^{2}\otimes C^{n} span after partial
conjugation the whole space. On the other hand, already in the case of
C^{3}\otimes C^{3} Hilbert space, there exist DEWs for which (iii) does not
imply (i). Consequently, either (i) does not imply (ii), or (ii) does not imply
(iii), and the above transparent characterization obeyed by qubit-qunit DEWs,
does not hold in general.
Chinese: 纠缠见证（EWs）是量子系统中最重要的纠缠检测器之一。尽管如此，它们的完整特征，特别是关于最优性的概念，即使在可分解的情况下，仍然缺失。在这里，我们表明，对于任何量子比特-量子单元可分解纠缠见证（DEW）W，以下三个陈述是等价的：（i）满足 \bra{e,f}W\ket{e,f}=0 的乘积向量集张成相应的希尔伯特空间，（ii）W是最优的，（iii）W=Q^{\Gamma}，其中Q表示一个在完全纠缠子空间（CES）上支持的正算子，\Gamma代表部分转置。虽然 $(i)\Rightarrow(ii)$ 和 $(ii)\Rightarrow(iii)$ 的含义是已知的，但在这里我们证明了 $(iii)$ 蕴含 $(i)$。这是这样一个更普遍事实的结果，即乘积向量与 C^{2}\otimes C^{n} 中的任何CES正交，在部分共轭后张成整个空间。另一方面，即使在 C^{3}\otimes C^{3} 希尔伯特空间的情况下，也存在DEWs，对于这些DEWs，（iii）不蕴含（i）。因此，要么（i）不蕴含（ii），要么（ii）不蕴含（iii），并且上述qubit-qunit DEWs遵循的透明特征在一般情况下不成立。
|
English: Three different special quasirandom structures (SQS) of the substitutional
hcp $A_{1-x}B_x$ binary random solutions ($x=0.25$, 0.5, and 0.75) are
presented. These structures are able to mimic the most important pair and
multi-site correlation functions corresponding to perfectly random hcp
solutions at those compositions. Due to the relatively small size of the
generated structures, they can be used to calculate the properties of random
hcp alloys via first-principles methods. The structures are relaxed in order to
find their lowest energy configurations at each composition. In some cases, it
was found that full relaxation resulted in complete loss of their parental
symmetry as hcp so geometry optimizations in which no local relaxations are
allowed were also performed. In general, the first-principles results for the
seven binary systems (Cd-Mg, Mg-Zr, Al-Mg, Mo-Ru, Hf-Ti, Hf-Zr, and Ti-Zr) show
good agreement with both formation enthalpy and lattice parameters measurements
from experiments. It is concluded that the SQS's presented in this work can be
widely used to study the behavior of random hcp solutions.
Chinese: 介绍了三种不同的特殊准随机结构（SQS）的替换型hcp $A_{1-x}B_x$ 二元随机溶液（$x=0.25$、0.5和0.75）。这些结构能够模拟出在相应组成下完美随机hcp溶液最重要的对和多站点相关函数。由于生成的结构相对较小，它们可以通过第一性原理方法来计算随机hcp合金的性质。为了在每个组成下找到它们的最低能量配置，这些结构被进行了松弛处理。在某些情况下，发现完全松弛导致了它们作为hcp的母体对称性的完全丧失，因此也进行了不允许局部松弛的几何优化。总的来说，七个二元系统（Cd-Mg、Mg-Zr、Al-Mg、Mo-Ru、Hf-Ti、Hf-Zr和Ti-Zr）的第一性原理结果与实验中测量的形成焓和晶格参数测量结果吻合良好。因此，可以得出结论，本文中提出的SQS可以广泛用于研究随机hcp溶液的行为。
|
English: In this work, a new model of effective lift-off threshold of oxide/metal
target is presented. The influence of nonlinear processes in the oxide layer on
its removal from the metallic samples using picosecond laser was investigated.
Nonlinear and saturable absorption in the layer was incorporated into modeling
for prediction of effective laser lift-off threshold fluence change with
varying peak intensities in z-scan type experiment for the first time. The new
model coincides well with the experimental results.
Chinese: 在这项工作中，提出了一种新的氧化物/金属靶材有效剥离阈值的模型。研究了氧化物层中非线性过程对其从金属样品中用皮秒激光去除的影响。首次将层中的非线性及饱和吸收纳入建模中，以预测随着z扫描实验中峰值强度的变化，有效激光剥离阈值的荧光强度变化。新的模型与实验结果吻合良好。
|
English: Rapidly Exploring Random Trees (RRT) is one of the most widely used
algorithms for motion planning in the field of robotics. To reduce the
exploration time, RRT-Connect was introduced where two trees are simultaneously
formed and eventually connected. Probabilistic RRT used the concept of position
probability map to introduce goal biasing for faster convergence. In this
paper, we propose a modified method to combine the pRRT and RRT-Connect
techniques and obtain a feasible trajectory around the obstacles quickly.
Instead of forming a single tree from the start point to the destination point,
intermediate goal points are selected around the obstacles. Multiple trees are
formed to connect the start, destination, and intermediate goal points. These
partial trees are eventually connected to form an overall safe path around the
obstacles. The obtained path is tracked using an MPC + Stanley controller which
results in a trajectory with control commands at each time step. The
trajectories generated by the proposed methods are more optimal and in
accordance with human intuition. The algorithm is compared with the standard
RRT and pRRT for studying its relative performance.
Chinese: 快速探索随机树（RRT）是机器人领域运动规划中最广泛使用的算法之一。为了减少探索时间，引入了RRT-Connect，该方法同时形成两棵树并最终连接。概率RRT利用位置概率图的概念引入目标偏置，以实现更快收敛。在本文中，我们提出了一种改进方法，结合pRRT和RRT-Connect技术，快速获取绕障碍物的可行轨迹。该方法不是从一开始就形成从起点到终点的单棵树，而是在障碍物周围选择中间目标点。通过形成多棵树连接起点、终点和中间目标点，这些部分树最终被连接形成绕障碍物的整体安全路径。所得路径通过MPC+Stanley控制器进行跟踪，从而在每个时间步生成控制指令。所提出方法生成的轨迹更优，且符合人类直觉。该算法与标准RRT和pRRT进行了比较，以研究其相对性能。
|
English: Neuromorphic devices, leveraging novel physical phenomena, offer a promising
path toward energy-efficient hardware beyond CMOS technology by emulating
brain-inspired computation. However, their progress is often limited to
proof-of-concept studies due to the lack of flexible spiking neural network
(SNN) algorithm frameworks tailored to device-specific characteristics, posing
a significant challenge to scalability and practical deployment. To address
this, we propose QUEST, a unified co-design framework that directly trains SNN
for emerging devices featuring multilevel resistances. With Skyrmionic Magnetic
Tunnel Junction (Sk-MTJ) as a case study, experimental results on the CIFAR-10
dataset demonstrate the framework's ability to enable scalable on-device SNN
training with minimal energy consumption during both feedforward and
backpropagation. By introducing device mapping pattern and activation operation
sparsity, QUEST achieves effective trade-offs among high accuracy (89.6%), low
bit precision (2-bit), and energy efficiency (93 times improvement over the
ANNs). QUEST offers practical design guidelines for both the device and
algorithm communities, providing insights to build energy-efficient and
large-scale neuromorphic systems.
Chinese: 神经形态器件利用新型物理现象，通过模拟脑启发计算，为超越CMOS技术的节能硬件提供了有前景的途径。然而，由于缺乏针对器件特定特性的灵活脉冲神经网络(SNN)算法框架，其进展往往局限于概念验证研究，这对可扩展性和实际部署构成了重大挑战。为解决这一问题，我们提出了QUEST，一个统一的协同设计框架，直接训练适用于具有多级电阻特性的新兴器件的SNN。以斯格明子磁性隧穿结(Sk-MTJ)为例，在CIFAR-10数据集上的实验结果表明，该框架能够实现具有极低能耗的器件内SNN训练，能耗在正向传播和反向传播过程中均最小。通过引入器件映射模式和激活操作稀疏性，QUEST在89.6%的高精度、2比特的低比特精度和93倍能耗提升之间实现了有效权衡。QUEST为器件和算法社区提供了实用设计指南，为构建节能型大规模神经形态系统提供了洞见。
|
English: Heterotic string compactifications can be conveniently described in the
language of (2,0) gauged linear sigma models (GLSMs). Such models allow for
Fayet-Iliopoulos (FI)-terms, which can be interpreted as Kahler parameters and
axions on the target space geometry. We show that field dependent non-gauge
invariant FI-terms lead to a Green-Schwarz-like mechanism on the worldsheet
which can be used to cancel worldsheet anomalies. However, given that these
FI-terms are constrained by quantization conditions due to worldsheet gauge
instantons, the anomaly conditions turn out to be still rather constraining.
Field dependent non-gauge invariant FI-terms result in non-Kahler, i.e.
torsional, target spaces in general. When FI-terms involve logarithmic terms,
the GLSM seems to describe the heterotic string in the presence of
Neveu-Schwarz (NS)5 branes. In particular, when the gauge bundle overcloses the
Bianchi identities, the GLSM describes a decompactified target space geometry
due to anti-NS5 branes.
Chinese: 异构弦的紧化可以方便地用(2,0)规范线性σ模型（GLSMs）的语言来描述。这样的模型允许存在Fayet-Iliopoulos（FI）项，这些项可以解释为目标空间几何中的Kähler参数和轴子。我们表明，场依赖的非规范不变FI项在世界面上导致类似于Green-Schwarz的机制，这可以用来消除世界面异常。然而，由于这些FI项受到世界面规范瞬变的量子化条件约束，异常条件仍然相当具有约束力。场依赖的非规范不变FI项通常导致非Kähler，即扭结的目标空间。当FI项涉及对数项时，GLSM似乎描述了存在Neveu-Schwarz（NS）5-branes的异构弦。特别是，当规范包络覆盖Bianchi恒等式时，由于反NS5-branes的存在，GLSM描述了一个去紧化的目标空间几何。
|
English: Future cosmological data may be sensitive to the effects of a finite sum of
neutrino masses even as small as ~0.06 eV, the lower limit guaranteed by
neutrino oscillation experiments. We show that a cosmological detection of
neutrino mass at that level would improve by many orders of magnitude the
existing limits on neutrino lifetime, and as a consequence on neutrino secret
interactions with (quasi-)massless particles as in majoron models. On the other
hand, neutrino decay may provide a way-out to explain a discrepancy <~ 0.1 eV
between cosmic neutrino bounds and Lab data.
Chinese: 未来的宇宙学数据可能对一小于0.06 eV的有限中微子质量之和敏感，这一下限由中微子振荡实验保证。我们表明，一个在那种水平上的宇宙学中微子质量探测将显著提高现有中微子寿命的限制，并因此对中微子与（准）无质量粒子之间的秘密相互作用（如大宇子模型中）的限制。另一方面，中微子衰变可能提供一种解释宇宙中微子界限与实验室数据之间差异的方法，该差异约为0.1 eV。
|
English: In this work, we tackle the problems of efficiency and scalability for
predictive coding networks (PCNs) in machine learning. To do so, we propose a
library, called PCX, that focuses on performance and simplicity, and use it to
implement a large set of standard benchmarks for the community to use for their
experiments. As most works in the field propose their own tasks and
architectures, do not compare one against each other, and focus on small-scale
tasks, a simple and fast open-source library and a comprehensive set of
benchmarks would address all these concerns. Then, we perform extensive tests
on such benchmarks using both existing algorithms for PCNs, as well as
adaptations of other methods popular in the bio-plausible deep learning
community. All this has allowed us to (i) test architectures much larger than
commonly used in the literature, on more complex datasets; (ii)~reach new
state-of-the-art results in all of the tasks and datasets provided;
(iii)~clearly highlight what the current limitations of PCNs are, allowing us
to state important future research directions. With the hope of galvanizing
community efforts towards one of the main open problems in the field,
scalability, we release code, tests, and benchmarks. Link to the library:
https://github.com/liukidar/pcx
Chinese: 在本工作中，我们针对机器学习中的预测编码网络（PCNs）的效率和可扩展性问题进行了研究。为此，我们提出了一套名为PCX的库，该库专注于性能和简洁性，并使用它来实现一系列标准基准供社区在实验中使用。由于该领域大多数工作都提出了自己的任务和架构，不相互比较，且专注于小型任务，因此一个简单快速的开源库和一套全面的基准测试将能够解决所有这些问题。然后，我们使用现有的PCNs算法以及生物启发深度学习社区中其他方法的适应版本，对这些基准进行了广泛的测试。所有这些都使我们能够：(i) 在更复杂的数据集上测试远超文献中常用的架构；(ii) 在所有提供的任务和数据集上达到新的最佳性能；(iii) 明确指出当前PCNs的局限性，使我们能够明确重要的未来研究方向。怀着推动社区为解决该领域的主要开放问题之一——可扩展性——而共同努力的希望，我们发布了代码、测试和基准测试。库的链接：https://github.com/liukidar/pcx
|
English: In this paper, we investigate maximum distance separable (MDS) codes based
group coded caching in fog radio access networks (F-RANs). The goal is to
minimize the average fronthaul rate under nonuniform file popularity. Firstly,
an MDS codes and file grouping based coded placement scheme is proposed to
provide coded packets and allocate more cache to the most popular files
simultaneously. Next, a fog access point (F-AP) grouping based coded delivery
scheme is proposed to meet the requests for files from different groups.
Furthermore, a closed-form expression of the average fronthaul rate is derived.
Finally, the parameters related to the proposed coded caching scheme are
optimized to fully utilize the gains brought by MDS codes and file grouping.
Simulation results show that our proposed scheme obtains significant
performance improvement over several existing caching schemes in terms of
fronthaul rate reduction.
Chinese: 在这篇论文中，我们研究了基于分组编码的雾无线电接入网络（F-RANs）中的最大距离可分（MDS）码。目标是降低非均匀文件流行度下的平均前传速率。首先，提出了一种基于MDS码和文件分组的编码放置方案，以同时提供编码数据包并将更多缓存分配给最受欢迎的文件。接着，提出了一种基于雾接入点（F-AP）分组的编码交付方案，以满足不同组别对文件的请求。此外，推导出了平均前传速率的闭式表达式。最后，优化了与所提出的编码缓存方案相关的参数，以充分利用MDS码和文件分组带来的收益。仿真结果表明，我们提出的方案在降低前传速率方面，相对于几个现有的缓存方案，获得了显著的性能提升。
|
English: To boost the performance, deep neural networks require deeper or wider
network structures that involve massive computational and memory costs. To
alleviate this issue, the self-knowledge distillation method regularizes the
model by distilling the internal knowledge of the model itself. Conventional
self-knowledge distillation methods require additional trainable parameters or
are dependent on the data. In this paper, we propose a simple and effective
self-knowledge distillation method using a dropout (SD-Dropout). SD-Dropout
distills the posterior distributions of multiple models through a dropout
sampling. Our method does not require any additional trainable modules, does
not rely on data, and requires only simple operations. Furthermore, this simple
method can be easily combined with various self-knowledge distillation
approaches. We provide a theoretical and experimental analysis of the effect of
forward and reverse KL-divergences in our work. Extensive experiments on
various vision tasks, i.e., image classification, object detection, and
distribution shift, demonstrate that the proposed method can effectively
improve the generalization of a single network. Further experiments show that
the proposed method also improves calibration performance, adversarial
robustness, and out-of-distribution detection ability.
Chinese: 为了提升性能，深度神经网络需要更深或更宽的网络结构，这涉及到巨大的计算和内存成本。为了缓解这一问题，自我知识蒸馏方法通过蒸馏模型自身的内部知识来规范模型。传统的自我知识蒸馏方法需要额外的可训练参数或依赖于数据。在本文中，我们提出了一种简单而有效的使用dropout（SD-Dropout）的自我知识蒸馏方法。SD-Dropout通过dropout抽样蒸馏多个模型的后续分布。我们的方法不需要任何额外的可训练模块，不依赖于数据，并且只需要简单的操作。此外，这种方法可以轻松地与各种自我知识蒸馏方法相结合。我们在工作中提供了对前向和反向KL散度的理论分析和实验分析。在多种视觉任务上的大量实验，即图像分类、目标检测和分布偏移，表明所提出的方法可以有效地提高单个网络的泛化能力。进一步的实验还表明，所提出的方法也提高了校准性能、对抗鲁棒性和分布外检测能力。
|
English: We study the involutions belonging to the class of 321 avoiding permutations.
We calculate the algebraic generating functions of the set containing the
involutions avoiding 321 and of some of its subsets. Precisely we determine the
algebraic generating functions of the involutions that are expansions of 12, of
those expansions of 21, of the simple ones and of their expansions. The
graphics of the simple involutions are caracterized. Being the simple
involutions avoiding 321 counted by Riordan's numbers, a combinatoric
interpretation of the results is illustrated through a class of Motzkin paths.
Another interpretation is given through Dyck paths.
Chinese: 我们研究属于321避免排列类的自同构。
我们计算包含避免321的自同构及其某些子集的代数生成函数。具体来说，我们确定了12的展开、21的展开、简单自同构及其展开的代数生成函数。简单自同构的图形被特征化。由于简单自同构避免321的计数由Riordan数给出，通过一类Motzkin路径展示了结果的组合解释。另一种解释是通过Dyck路径给出的。
|
English: Motivated by the possibility of combining spintronics with molecular
structures, we investigate the conditions for the appearance of
spin-polarization in low-dimensional tubular systems by contacting them to a
magnetic substrate. We derive a set of general expressions describing the
charge transfer between the tube and the substrate and the relative energy
costs. The mean-field solution of the general expressions provides an
insightful formula for the induced spin-polarization. Using a tight-binding
model for the electronic structure we are able to estimate the magnitude and
the stability of the induced moment. This indicates that a significant magnetic
moment in carbon nanotubes can be observed.
Chinese: 受将自旋电子学与分子结构相结合的可能性所激励，我们通过将低维管状系统接触磁性衬底来研究其出现自旋极化的条件。我们推导出一组描述管状与衬底之间电荷转移及其相对能量成本的通用表达式。这些通用表达式的平均场解提供了一种对诱导自旋极化的深刻公式。利用电子结构的紧束缚模型，我们能够估计诱导磁矩的大小和稳定性。这表明在碳纳米管中可以观察到显著的磁矩。
|
English: Very old halo stars were previously found to show at least four different
abundance 'anomalies', which models of fast rotating massive stars (spinstars)
can successfully account for: rise of N/O and C/O, low 12C/13C and a
primary-like evolution of Be and B. Here we show the impact of these same stars
in the enrichment of Sr and Ba in the early Universe. We study if the s-process
production of fast rotating massive stars can offer an explanation for the
observed spread in [Sr/Ba] ratio in halo stars with metallicity [Fe/H]< -2.5.
By means of a chemical inhomogeneous model we compute the enrichment of Sr and
Ba by massive stars in the Galactic halo. Our model takes into account, for the
first time, the contribution of spinstars. Our model (combining an r-process
contribution with a s-process from fast rotating massive stars) is able to
reproduce for the first time the observed scatter in the [Sr/Ba] ratio at
[Fe/H]< -2.5. Toward higher metallicities, the stochasticity of the star
formation fades away due to the increasing number of exploding and enriching
stars, and as a consequence the predicted scatter decreases. Our scenario is
again based on the existence of spinstars in the early Universe. Very old halo
stars were previously found to show at least four other abundance 'anomalies',
which rotating models of massive stars can successfully account for. Our
results provide a 5th independent signature of the existence of fast rotating
massive stars: an early enrichment of the Universe in s-process elements.
Chinese: 先前发现非常古老的晕星表现出至少四种不同的丰度“异常”，快速旋转的大质量星（spinstars）的模型能够成功解释这些异常：N/O和C/O的升高、低12C/13C以及Be和B的类初始演化。这里我们展示了这些恒星对早期宇宙中锶（Sr）和钡（Ba）富集的影响。我们研究了快速旋转的大质量星的s过程产物是否能够解释金属丰度[Fe/H]< -2.5的晕星中观测到的[Sr/Ba]比率分布。通过化学非均匀模型，我们计算了银河晕中由大质量星引起的Sr和Ba的富集。我们的模型首次考虑了spinstars的贡献。我们的模型（结合了r过程贡献和快速旋转大质量星的s过程）首次能够重现[Fe/H]< -2.5的[Sr/Ba]比率观测散布。向更高的金属丰度方向，由于爆炸和富集的恒星数量增加，恒星形成的随机性逐渐减弱，因此预测的散布减小。我们的情景再次基于早期宇宙中存在spinstars的假设。先前发现非常古老的晕星表现出至少四种其他丰度“异常”，旋转的大质量星模型能够成功解释这些异常。我们的结果为快速旋转的大质量星的存在提供了第五个独立的证据：早期宇宙在s过程元素上的富集。
|
English: The computation of two and three point functions in the Coulomb gas free
field approach to string theory in the SL(2,R)/U(1) black hole background is
reviewed. An interesting relation arises when comparing the results obtained
using two different screening operators. The formalism is then modified to
study string theory propagating in AdS$_3$ which is considered as the direct
product of the SL(2)/U(1) coset times a timelike free boson. This
representation allows to naturally include the spectral flow symmetry and
winding number in vertex operators and correlation functions. Two and three
point tachyon amplitudes are computed in this new scenario and the results
coincide with previous reports in the literature. Novel expressions are found
for processes violating winding number conservation.
Chinese: 对SL(2,R)/U(1)黑洞背景中库仑气体自由场方法弦论中两点函数和三点函数的计算进行了综述。当比较使用两种不同筛选算符得到的结果时，会出现一个有趣的关系。随后修改了形式体系，以研究在AdS₃中传播的弦论，AdS₃被视为SL(2)/U(1)陪集与一个类时自由玻色子的直积。这种表示法允许自然地将谱流对称性和缠绕数包含在顶点算符和相关函数中。在这个新场景中计算了两点函数和三点函数张量振幅，结果与文献中的先前报道一致。对于违反缠绕数守恒的过程，发现了新的表达式。
|
English: Let $D\subset\mathbb C^n$ be a bounded, strongly pseudoconvex domain whose
boundary $bD$ satisfies the minimal regularity condition of class $C^2$, and
let $S_\omega$ denote the Cauchy--Szeg\H{o} projection defined with respect to
(any) positive continuous multiple $\omega$ of induced Lebesgue measure for the
boundary of $D$. We characterize compactness and boundedness (the latter with
explicit bounds) of the commutator $[b, S_\omega]$ in the Lebesgue space
$L^p(bD, \Omega_p)$ where $\Omega_p$ is any measure in the Muckenhoupt class
$A_p(bD)$, $1<p<\infty$. We next fix $p =2$ and we let $S_{\Omega_2}$ denote
the Cauchy--Szeg\H{o} projection defined with respect to (any) measure
$\Omega_2 \in A_2(bD)$, which is the largest class of reference measures for
which a meaningful notion of Cauchy-Leray measure may be defined. We
characterize boundedness and compactness in $L^2(bD, \Omega_2)$ of the
commutator $\displaystyle{[b,S_{\Omega_2}]}$.
Chinese: 设 $D\subset\mathbb C^n$ 为一个有界、强拟凸域，其边界 $bD$ 满足类 $C^2$ 的最小正则性条件，并令 $S_\omega$ 表示相对于 $D$ 边界的诱导勒贝格测度的任意正连续倍数 $\omega$ 定义的柯西-泽戈投影。我们刻画了在勒贝格空间 $L^p(bD, \Omega_p)$ 中，其中 $\Omega_p$ 是 Muckenhoupt 类 $A_p(bD)$ 中的任意测度，$1<p<\infty$，伴随算子 $[b, S_\omega]$ 的紧致性和有界性（后者具有显式界限）。接下来，我们固定 $p =2$，并令 $S_{\Omega_2}$ 表示相对于 $A_2(bD)$ 中的（任意）测度 $\Omega_2$ 定义的柯西-泽戈投影，这是可以定义有意义的柯西-勒雷测度的大类参考测度。我们刻画了在 $L^2(bD, \Omega_2)$ 中伴随算子 $\displaystyle{[b,S_{\Omega_2}]}$ 的有界性和紧致性。
|
English: We present results from our recent lattice QCD study of $N\pi$ scattering in
the positive-parity nucleon channel, where the puzzling Roper resonance
$N^*(1440)$ resides in experiment. Using a variety of hadron operators, that
include $qqq$-like, $N\pi$ in $p$-wave and $N\sigma$ in $s$-wave, we
systematically extract the excited lattice spectrum in the nucleon channel up
to 1.65 GeV. Our lattice results indicate that N$\pi$ scattering in the elastic
approximation alone does not describe a low-lying Roper. Coupled channel
effects between $N\pi$ and $N\pi\pi$ seem to be crucial to render a low-lying
Roper in experiment, reinforcing the notion that this state could be a
dynamically generated resonance. After giving a brief motivation for studying
the Roper channel and the relevant technical details to this study, we will
discuss the results and the conclusions based on our lattice investigation and
in comparison with other lattice calculations.
Chinese: 我们展示了我们最近对 $N\pi$ 散射在正宇称奇数通道的研究结果，其中实验中令人费解的罗珀共振 $N^*(1440)$ 就存在于这个通道。通过一系列包含 $qqq$ 型、$p$ 波 $N\pi$ 和 $s$ 波 $N\sigma$ 的强子算子，我们系统地提取了核子通道内激发的格点谱，能量上限为 1.65 GeV。我们的格点结果表明，仅通过弹性近似下的 $N\pi$ 散射无法描述一个低能的罗珀。$N\pi$ 和 $N\pi\pi$ 之间的耦合效应似乎是形成实验中低能罗珀的关键因素，这强化了该状态可能是动态生成的共振的观点。在简要介绍了研究罗珀通道的动机及相关技术细节之后，我们将讨论基于格点研究的结果和结论，并与其他的格点计算结果进行比较。
|
English: Strong gravitational lensing of distant supernovae (SNe), particularly Type
Ia's, has some exploitable properties not available when other sorts of
cosmologically distant sources are lensed. One such property is that the
``standard candle'' nature of the SN at peak brightness allows a direct
determination of the lensing magnification factor for each well observed image.
Another is that the duration of an SN event is of the same order as the
differential time delays between the various lens images. The comparable time
scales of the photometric event and the time delay invite a variety of
applications, including high precision measurements of the delay and the
targeting of especially interesting phases of the explosion for intensive
observation when they appear in trailing images. As an initial exploration of
these possibilities we present calculations of SN lensing statistics in a
``concordance cosmology''. We emphasize magnification and time delay effects.
Plausible SN surveys, such as the proposed SNAP space mission, would discover
several to some tens of strongly lensed SNe Ia per year, and at least a few of
these will be at redshifts well beyond those that would be accessible via
unlensed events. The total number of such anomalously high redshift SNe Ia will
be a useful test of high redshift star formation models. SN surveys of finite
duration will, of course, miss the appearance of some images; we quantify this
selection bias. Finally, we investigate how well the appearance of trailing
images can be predicted based on various amounts of available information on
the lensing event. Knowledge of the magnification factor for the leading image
makes it possible to predict the appearance of a trailing image relatively
accurately if the lens redshift is also known. (Abridged)
Chinese: 强引力透镜效应对遥远超新星（SNe），尤其是Ia型超新星，具有一些在其他宇宙遥远源透镜效应中不可利用的特性。其中一个特性是，在峰值亮度时，超新星的“标准烛光”性质允许直接确定每个观测良好的图像的透镜放大因子。另一个特性是，超新星事件的持续时间与各种透镜图像之间的时间延迟差相同。光测事件和时间延迟的可比时间尺度邀请了许多应用，包括高精度测量延迟和当它们出现在尾随图像中时，针对爆炸特别有趣阶段的密集观测。作为对这些可能性的初步探索，我们展示了在“一致性宇宙学”中计算超新星透镜统计的方法。我们强调放大和时间延迟效应。可能的超新星调查，如拟议的SNAP太空任务，每年将发现几个到几十个强透镜Ia型超新星，其中至少有几个将位于通过无透镜事件无法到达的红移之外。这种异常高红移Ia型超新星的总数将是对高红移星形成模型的有用测试。当然，有限持续时间的超新星调查将错过一些图像的出现；我们量化了这种选择偏差。最后，我们研究了基于关于透镜事件的各种可用信息，尾随图像的出现如何被预测。如果已知前导图像的放大因子，并且也知道了透镜红移，那么就有可能相对准确地预测尾随图像的出现。（摘要）
|
English: Let $A(k)u(k)=f(k) (1)$ be an operator equation, $X$ and $Y$ are Banach
spaces, $k\in\Delta\subset\C$ is a parameter, $A(k):X\to Y$ is a map, possibly
nonlinear. Sufficient conditions are given for continuity of $u(k)$ with
respect to $k$. Necessary and sufficient conditions are given for the
continuity of $u(k)$ with respect to $k$ in the case of linear operators
$A(k)$.
Chinese: 设 $A(k)u(k)=f(k) (1)$ 为一个算子方程，$X$ 和 $Y$ 是Banach空间，$k\in\Delta\subset\C$ 是一个参数，$A(k):X\to Y$ 是一个映射，可能是非线性的。给出了$u(k)$关于$k$连续性的充分条件。在$A(k)$为线性算子的情况下，给出了$u(k)$关于$k$连续性的必要且充分条件。
|
English: Observations indicate that roughly 60% of the baryons may exist in a Warm-Hot
Intergalactic Medium (WHIM) at low redshifts. Following up on previous results
showing that gas is released through galaxy mergers, we use a semi-analytic
technique to estimate the fraction of gas mass lost from haloes solely due to
mergers. We find that up to ~25% of the gas in a halo can unbind over the
course of galaxy assembly. This process does not act preferentially on smaller
mass haloes; bigger haloes \emph{always} release larger amounts of gas in a
given volume of the Universe. However, if we include multi-phase gas accretion
onto haloes, we find that only a few percent is unbound. We conclude that
either non-gravitational processes may be in play to heat up the gas in the
galaxies prior to unbinding by mergers or most of the baryons in the WHIM have
never fallen into virialised dark matter haloes. We present a budget for
stocking the WHIM compiled from recent work.
Chinese: 观察表明，大约60%的重子可能存在于低红移处的温暖-热宇宙介质（WHIM）中。在追踪先前关于气体通过星系合并释放的结果后，我们采用半解析技术来估计由于合并而仅从晕中失去的气体质量的比例。我们发现，在星系形成过程中，一个晕中的高达约25%的气体可能会解绑。这个过程并不会优先作用于较小质量的晕；较大的晕在宇宙的特定体积中总是释放出更多的气体。然而，如果我们包括多相气体在晕上的累积，我们发现只有少数百分比会解绑。我们得出结论，要么非引力过程可能在起作用，在合并解绑之前加热星系中的气体，要么WHIM中的大部分重子从未落入引力稳定的暗物质晕中。我们展示了从最近的工作中汇编的WHIM库存预算。
|
English: For a finite binary string $x$ its logical depth $d$ for significance $b$ is
the shortest running time of a program for $x$ of length $K(x)+b$. There is
another definition of logical depth. We give a new proof that the two versions
are close. There is an infinite sequence of strings of consecutive lengths such
that for every string there is a $b$ such that incrementing $b$ by 1 makes the
associated depths go from incomputable to computable. The maximal gap between
depths resulting from incrementing appropriate $b$'s by 1 is incomputable. The
size of this gap is upper bounded by the Busy Beaver function. Both the upper
and the lower bound hold for the depth with significance 0. As a consequence,
the minimal computation time of the associated shortest programs rises faster
than any computable function but not so fast as the Busy Beaver function.
Chinese: 对于一个有限二进制字符串 $x$，其对于重要性 $b$ 的逻辑深度 $d$ 是长度为 $K(x)+b$ 的 $x$ 的程序的最短运行时间。还有一个逻辑深度的定义。我们给出一个新的证明，表明这两个版本非常接近。存在一个字符串长度连续的无限序列，对于每个字符串，都存在一个 $b$，使得将 $b$ 增加 1 使得相关的深度从不可计算变为可计算。通过适当增加 $b$ 的值，深度之间的最大差距是不可计算的。这个差距的大小被忙海狸函数的上界所限制。对于深度为 0 的情况，上下界都成立。因此，相关最短程序的最小计算时间比任何可计算函数增长得更快，但并不像忙海狸函数那样快。
|
English: We report the experimental evidence of the ac Josephson effect in a
transition edge sensor (TES) operating in a frequency domain multiplexer and
biased by ac voltage at MHz frequencies. The effect is observed by measuring
the non-linear impedance of the sensor. The TES is treated as a weakly linked
superconducting system and within the resistively shunted junction model
framework. We provide a full theoretical explanation of the results by finding
the analytic solution of the non-inertial Langevian equation of the system and
calculating the non-linear response of the detector to a large ac bias current
in the presence of noise.
Chinese: 我们报告了在频率域复用器中运行的过渡边缘传感器（TES）在MHz频率的交流电压偏置下实验证明的交流约瑟夫森效应。通过测量传感器的非线性阻抗来观察该效应。TES被视为一个弱耦合的超导系统，并在电阻性旁路结模型框架内。我们通过找到系统的非惯性朗之万方程的解析解，并计算在噪声存在的情况下，探测器对大交流偏置电流的非线性响应，对结果提供了全面的理论解释。
|
English: In this article we present a generalization of the electron localization
function (ELF) that can be used to analyze time-dependent processes. The
time-dependent ELF allows the time-resolved observation of the formation, the
modulation, and the breaking of chemical bonds, and can thus provide a visual
understanding of complex reactions involving the dynamics of excited electrons.
We illustrate the usefulness of the time-dependent ELF by two examples: the
pi-pi* transition induced by a laser field, and the destruction of bonds and
formation of lone pairs in a scattering process.
Chinese: 在本文中，我们提出了一种电子局域化函数（ELF）的推广，该推广可用于分析时间依赖过程。时间依赖的ELF允许对化学键的形成、调制和断裂进行时间分辨观察，从而可以提供对涉及激发电子动力学复杂反应的视觉理解。我们通过两个例子说明了时间依赖ELF的有用性：激光场诱导的π-π*跃迁，以及散射过程中键的破坏和孤对的形成。
|
English: We investigate in detail the parameter space of active-sterile neutrino
oscillations that amplifies neutrino chemical potentials at the epoch of Big
Bang Nucleosynthesis. We calculate the magnitude of the amplification and show
evidences of chaos in the amplification process. We also discuss the
implications of the neutrino chemical potential amplification in the Big Bang
Nucleosynthesis. It is shown that with a $\sim 1$ eV $\nue$, the amplification
of its chemical potential by active-sterile neutrino oscillations can lower the
effective number of neutrino species at Big Bang Nucleosynthesis to
significantly below 3.
Chinese: 我们详细研究了活性-无味中微子振荡的参数空间，这种振荡在宇宙大爆炸核合成时期放大了中微子的化学势。我们计算了放大量级，并在放大过程中展示了混沌的证据。我们还讨论了中微子化学势放大对大爆炸核合成的影响。结果显示，在约1 eV的$\nue$中微子下，活性-无味中微子振荡对其化学势的放大可以将大爆炸核合成时期中微子种类的有效数量降低到显著低于3的数量。
|
English: Many data mining and analytical tasks rely on the abstraction of networks
(graphs) to summarize relational structures among individuals (nodes). Since
relational data are often sensitive, we aim to seek effective approaches to
generate utility-preserved yet privacy-protected structured data. In this
paper, we leverage the differential privacy (DP) framework to formulate and
enforce rigorous privacy constraints on deep graph generation models, with a
focus on edge-DP to guarantee individual link privacy. In particular, we
enforce edge-DP by injecting proper noise to the gradients of a link
reconstruction-based graph generation model, while ensuring data utility by
improving structure learning with structure-oriented graph discrimination.
Extensive experiments on two real-world network datasets show that our proposed
DPGGAN model is able to generate graphs with effectively preserved global
structure and rigorously protected individual link privacy.
Chinese: 许多数据挖掘和分析任务依赖于网络（图）的抽象来总结个体（节点）之间的关系结构。由于关系数据通常很敏感，我们旨在寻求有效的途径来生成既保留了效用又保护了隐私的结构化数据。在本文中，我们利用差分隐私（DP）框架来制定和执行对深度图生成模型的严格隐私约束，重点关注边缘-DP以保证个体链接的隐私。特别是，我们通过向基于链接重建的图生成模型的梯度注入适当的噪声来执行边缘-DP，同时通过改进结构导向的图判别来提高结构学习，以确保数据效用。在两个真实世界网络数据集上的大量实验表明，我们提出的DPGGAN模型能够生成具有有效保留全局结构和严格保护个体链接隐私的图。
|
English: We consider three Sturm--Liouville boundary value problems (the coercive ones
and the non-coercive one) in a bounded Lipschitz domain for the perturbed
Lam\'e operator with the boundary conditions of Robin type. We prove that the
problems are Fredholm ones in proper weighted Sobolev type spaces. The
conditions, providing the completeness of the root functions related to the
boundary value problem, are described.
Chinese: 我们考虑在Lamé算子的扰动下，具有Robin边界条件的三个Sturm--Liouville边界值问题（强约束问题和弱约束问题），这些问题定义在有界Lipschitz域内。我们证明了这些问题是适当的加权Sobolev空间中的Fredholm问题。我们还描述了保证边界值问题的根函数完备性的条件。
|
English: This paper explores the enhancement of small language models through
strategic dataset augmentation via ChatGPT-3.5-Turbo, in the domain of Natural
Language Inference (NLI). By employing knowledge distillation-based techniques
and synthetic dataset augmentation, we aim to bridge the performance gap
between large language models (LLMs) and small language models (SLMs) without
the immense cost of human annotation. Our methods involve two forms of
rationale generation--information extraction and informed reasoning--to enrich
the ANLI dataset. We then fine-tune T5-Small on these augmented datasets,
evaluating its performance against an established benchmark. Our findings
reveal that the incorporation of synthetic rationales significantly improves
the model's ability to comprehend natural language, leading to 1.3\% and 2.3\%
higher classification accuracy, respectively, on the ANLI dataset,
demonstrating the potential of leveraging LLMs for dataset augmentation. This
approach not only enhances the performance of smaller models on complex tasks
but also introduces a cost-effective method for fine-tuning smaller language
models. By advancing our understanding of knowledge distillation and
fine-tuning strategies, this work contributes to the ongoing effort to create
more capable and efficient NLP systems.
Chinese: 本文探讨了通过ChatGPT-3.5-Turbo进行战略数据集增强来提升小型语言模型的方法，在自然语言推理（NLI）领域进行研究。通过采用基于知识蒸馏的技术和合成数据集增强，我们旨在缩小大型语言模型（LLMs）和小型语言模型（SLMs）之间的性能差距，而无需巨大的标注成本。我们的方法涉及两种形式的推理生成——信息提取和有信息推理——以丰富ANLI数据集。然后，我们在这些增强的数据集上微调T5-Small，并评估其性能与一个已建立的基准进行对比。我们的发现表明，合成推理的引入显著提高了模型理解自然语言的能力，分别在ANLI数据集上提高了1.3%和2.3%的分类准确率，展示了利用LLMs进行数据集增强的潜力。这种方法不仅提高了小型模型在复杂任务上的性能，还引入了一种成本效益高的微调小型语言模型的方法。通过推进我们对知识蒸馏和微调策略的理解，这项工作为创建更强大和高效的NLP系统做出了贡献。
|
English: FPGA is a hardware architecture based on a matrix of programmable and
configurable logic circuits thanks to which a large number of functionalities
inside the device can be modified using a hardware description language. These
functionalities must often be secured especially when the context is sensitive
(military, banking, medical, legal, etc.). In this paper, we put forward an
efficient implementation of SIMON's block cipher algorithm using Xilinx Vivado
2018.2. The proposed design is analyzed through simulation on Xilinx Artix-7. A
prototype of our design is implemented using the xc7a35tcsg324-1 FPGA chip.
Performance and results are discussed.
Chinese: FPGA是一种基于可编程和可配置逻辑电路矩阵的硬件架构，通过该架构，设备内部的大量功能可以使用硬件描述语言进行修改。这些功能通常需要被保护，尤其是在敏感环境下（如军事、银行、医疗、法律等）。在本文中，我们提出了使用Xilinx Vivado 2018.2对SIMON分组密码算法进行高效实现的方法。所提出的方案通过在Xilinx Artix-7上进行仿真进行分析。我们设计的原型使用xc7a35tcsg324-1 FPGA芯片实现。讨论了性能和结果。
|
English: We present the results of a numerical study of the fluid $f$, $p$ and the
gravitational $w$ modes for increasingly relativistic nonrotating polytropes.
The results for $f$ and $w$-modes are in good agreement with previous data for
uniform density stars, which supports an understanding of the nature of the
gravitational wave modes based on the uniform density data. We show that the
$p$-modes can become extremely long-lived for some relativistic stars. This
effect is attributed to the change in the perturbed density distribution as the
star becomes more compact.
Chinese: 我们展示了对越来越具相对论性的非旋转多方体流体$f$、$p$和重力$w$模式的数值研究结果。$f$模式和$w$模式的结果与均匀密度恒星的前期数据高度吻合，这支持了基于均匀密度数据对重力波模式性质的理解。我们表明，对于某些相对论性恒星，$p$模式可以变得极其长寿。这种现象归因于恒星在变得更致密时扰动密度分布的变化。
|
English: The proposal of hep-ph/0601236, that the laws of physics in flat spacetime
need be invariant only under a SIM(2) subgroup of the Lorentz group, is
extended to include supersymmetry. $\mathcal{N}=1$ SUSY gauge theories which
include SIM(2) couplings for the fermions in chiral multiplets are formulated.
These theories contain two conserved supercharges rather than the usual four.
Chinese: hep-ph/0601236的提议——即平坦时空中的物理定律只需在洛伦兹群的SO(2)子群下保持不变——被扩展以包含超对称。构建了包含手征多重态中费米子的SO(2)耦合的$\mathcal{N}=1$超对称规范理论。这些理论包含两个守恒超荷，而不是通常的四个。
|
English: Hyperbolic neural networks (HNNs) have been proved effective in modeling
complex data structures. However, previous works mainly focused on the
Poincar\'e ball model and the hyperboloid model as coordinate representations
of the hyperbolic space, often neglecting the Klein model. Despite this, the
Klein model offers its distinct advantages thanks to its straight-line
geodesics, which facilitates the well-known Einstein midpoint construction,
previously leveraged to accompany HNNs in other models. In this work, we
introduce a framework for hyperbolic neural networks based on the Klein model.
We provide detailed formulation for representing useful operations using the
Klein model. We further study the Klein linear layer and prove that the
"tangent space construction" of the scalar multiplication and parallel
transport are exactly the Einstein scalar multiplication and the Einstein
addition, analogous to the M\"obius operations used in the Poincar\'e ball
model. We show numerically that the Klein HNN performs on par with the
Poincar\'e ball model, providing a third option for HNN that works as a
building block for more complicated architectures.
Chinese: 双曲神经网络（HNNs）已被证明在建模复杂数据结构方面非常有效。然而，先前的研究主要关注庞加莱球模型和双曲抛物面模型作为双曲空间的坐标表示，常常忽略了克莱因模型。尽管如此，克莱因模型凭借其直线测地线提供了独特的优势，这有助于实现著名的爱因斯坦中点构造，以前曾利用这一构造来辅助其他模型中的HNNs。在这项工作中，我们引入了一个基于克莱因模型的双曲神经网络框架。我们提供了使用克莱因模型表示有用操作的详细公式。我们进一步研究了克莱因线性层，并证明了标量乘法和平行传输的“切空间构造”正好是爱因斯坦标量乘法和爱因斯坦加法，类似于在庞加莱球模型中使用的莫比乌斯操作。我们通过数值计算表明，克莱因HNN的表现与庞加莱球模型相当，为HNN提供了一种作为更复杂架构构建块的第三种选择。
|
English: Recently, a tensor factorization based method for a low tubal rank tensor
completion problem of a third order tensor was proposed, which performed better
than some existing methods. Tubal rank is only defined on one mode of third
order tensor without low rank structure in the other two modes. That is, low
rank structures on the other two modes are missing. Motivated by this, we first
introduce multi-tubal rank, and then establish a relationship between
multi-tubal rank and Tucker rank. Based on the multi-tubal rank, we propose a
novel low rank tensor completion model. For this model, a tensor factorization
based method is applied and the corresponding convergence anlysis is
established. In addition, spatio-temporal characteristics are intrinsic
features in video and internet traffic tensor data. To get better performance,
we make full use of such features and improve the established tensor completion
model. Then we apply tensor factorization based method for the improved model.
Finally, numerical results are reported on the completion of image, video and
internet traffic data to show the efficiency of our proposed methods. From the
reported numerical results, we can assert that our methods outperform the
existing methods.
Chinese: 最近，针对三阶张量低管秩张量补全问题提出了一种基于张量分解的方法，该方法性能优于一些现有方法。管秩仅在第三阶张量的一种模式上定义，而在其他两种模式上缺乏低秩结构。也就是说，其他两种模式上的低秩结构缺失。受此启发，我们首先引入多管秩，然后建立多管秩与Tucker秩之间的关系。基于多管秩，我们提出了一种新的低秩张量补全模型。对于该模型，应用了基于张量分解的方法，并建立了相应的收敛性分析。此外，时空特征是视频和互联网流量张量数据中的固有特征。为了获得更好的性能，我们充分利用这些特征，改进了已建立的张量补全模型。然后我们应用基于张量分解的方法对改进后的模型进行求解。最后，报告了图像、视频和互联网流量数据的补全结果，以展示我们提出方法的有效性。从报告的数值结果中，我们可以断言我们的方法优于现有方法。
|
English: We study spin-2 deformed-AKLT models on the square lattice, specifically a
two-parameter family of $O(2)$-symmetric ground-state wavefunctions as defined
by Niggemann, Kl\"umper, and Zittartz, who found previously that the phase
diagram consists of a N\'eel-ordered phase and a disordered phase which
contains the AKLT point. Using tensor-network methods, we not only confirm the
N\'eel phase but also find an XY phase with quasi-long-range order and a region
adjacent to it, within the AKLT phase, with very large correlation length, and
investigate the consequences of a perfectly factorizable point at the corner of
that phase.
Chinese: 我们研究了正方形格子上自旋-2变形的AKLT模型，具体是一个由Niggemann、Klumper和Zittartz定义的$O(2)$对称基态波函数的两参数族。他们之前发现相图由Néel有序相和无序相组成，后者包含AKLT点。利用张量网络方法，我们不仅确认了Néel相，还发现了一个具有准长程有序性的XY相以及相邻区域，在AKLT相内，具有非常长的相关长度，并研究了该相角落一个完美可约化点的后果。
|
English: We study the rectification of a two-dimensional thermal gas in a channel of
asymmetric dissipative walls. For an ensemble of smooth Lennard-Jones
particles, our numerical simulations reveal a non-monotonic dependence of the
flux on the thermostat temperature, channel asymmetry, and particle density,
with three distinct regimes. Theoretical arguments are developed to shed light
on the functional dependence of the flux on the model parameters.
Chinese: 我们研究了在不对称耗散壁的通道中二维热气体的整流。对于一组平滑的Lennard-Jones粒子，我们的数值模拟揭示了通量对恒温器温度、通道不对称性和粒子密度的非单调依赖性，存在三个不同的区域。为了阐明通量对模型参数的功能依赖性，我们发展了理论论证。
|
English: Neural rendering methods have significantly advanced photo-realistic 3D scene
rendering in various academic and industrial applications. The recent 3D
Gaussian Splatting method has achieved the state-of-the-art rendering quality
and speed combining the benefits of both primitive-based representations and
volumetric representations. However, it often leads to heavily redundant
Gaussians that try to fit every training view, neglecting the underlying scene
geometry. Consequently, the resulting model becomes less robust to significant
view changes, texture-less area and lighting effects. We introduce Scaffold-GS,
which uses anchor points to distribute local 3D Gaussians, and predicts their
attributes on-the-fly based on viewing direction and distance within the view
frustum. Anchor growing and pruning strategies are developed based on the
importance of neural Gaussians to reliably improve the scene coverage. We show
that our method effectively reduces redundant Gaussians while delivering
high-quality rendering. We also demonstrates an enhanced capability to
accommodate scenes with varying levels-of-detail and view-dependent
observations, without sacrificing the rendering speed.
Chinese: 神经网络渲染方法在学术和工业应用中显著提高了照片级真实的3D场景渲染。最近提出的3D高斯散布方法结合了基于原语表示和体积表示的优点，实现了最先进的渲染质量和速度。然而，它往往会导致大量冗余的高斯分布，试图适应每个训练视图，而忽略了场景的底层几何结构。因此，得到的模型对显著视角变化、无纹理区域和光照效果变得不那么鲁棒。我们引入了Scaffold-GS，它使用锚点来分布局部3D高斯分布，并根据视图内视锥体内的观察方向和距离实时预测它们的属性。基于神经网络高斯的重要性，我们开发了锚点增长和修剪策略，以可靠地提高场景覆盖范围。我们表明，我们的方法有效地减少了冗余的高斯分布，同时提供了高质量的渲染。我们还展示了增强的能力，以适应具有不同细节级别和视点相关观察的场景，而不会牺牲渲染速度。
|
English: We introduce a new definition of topological degree for a meaningful class of
operators which need not be continuous. Subsequently, we derive a number of
fixed point theorems for such operators. As an application, we deduce a new
existence result for first-order ODEs with discontinuous nonlinearities.
Chinese: 我们为需要不必连续的一类有意义的算子引入了一种新的拓扑度定义。随后，我们推导出这类算子的若干个不动点定理。作为一个应用，我们推导出一阶常微分方程在非线性项不连续时的一个新存在结果。
|
English: Neural-symbolic integration aims to combine the connectionist subsymbolic
with the logical symbolic approach to artificial intelligence. In this paper,
we first define the answer set semantics of (boolean) neural nets and then
introduce from first principles a class of neural logic programs and show that
nets and programs are equivalent.
Chinese: 神经符号整合旨在将连接主义的无符号方法与人工智能的逻辑符号方法相结合。在本文中，我们首先定义了（布尔）神经网络的答案集语义，然后从第一原理引入一类神经逻辑程序，并证明网络和程序是等价的。
|
English: Matrix pencils provide a robust method for finding simultaneous eigensystems
of mutually commuting degenerate operators. In this paper, we utilize these
techniques to investigate the quantum logical structures of the Peres-Mermin
square and the Greenberger-Horne-Zeilinger-Mermin configuration. Our analysis
uncovers analogous complete contradictions between classical and quantum
predictions in a four-dimensional system involving two spin-1/2 particles.
Chinese: 矩阵 pencil 提供了一种稳健的方法，用于寻找相互对易的简并算子的同时特征系统。在本文中，我们利用这些技术来研究佩雷斯-默尔明正方形和格林贝格-霍恩-齐林格-默尔明构型的量子逻辑结构。我们的分析揭示了一个涉及两个自旋为1/2的粒子的四维系统中，经典和量子预测之间存在类似的全然矛盾。
|
English: The problem of controlling a finite state Markov chain in the presence of an
adversary so as to ensure desired performance levels for a vector of objectives
is cast in the framework of Blackwell approachability. Relying on an elementary
two time scale construction a control scheme is proposed which ensures almost
sure convergence to the desired set regardless of the adversarial actions.
Chinese: 在存在对手的情况下，将控制有限状态马尔可夫链的问题，以确保一系列目标性能水平，置于布莱克威尔可达性框架中。依靠一个基本的两个时间尺度构造，提出了一种控制方案，无论对手采取何种行动，都能确保几乎必然收敛到期望的集合。
|
English: We present an optimization study of the Vision-Language Frontier Maps (VLFM)
applied to the Object Goal Navigation task in robotics. Our work evaluates the
efficiency and performance of various vision-language models, object detectors,
segmentation models, and multi-modal comprehension and Visual Question
Answering modules. Using the $\textit{val-mini}$ and $\textit{val}$ splits of
Habitat-Matterport 3D dataset, we conduct experiments on a desktop with limited
VRAM. We propose a solution that achieves a higher success rate (+1.55%)
improving over the VLFM BLIP-2 baseline without substantial success-weighted
path length loss while requiring $\textbf{2.3 times}$ less video memory. Our
findings provide insights into balancing model performance and computational
efficiency, suggesting effective deployment strategies for resource-limited
environments.
Chinese: 我们针对机器人领域中的物体目标导航任务，对视觉-语言前沿地图（Vision-Language Frontier Maps, VLFM）进行了优化研究。我们的工作评估了多种视觉-语言模型、物体检测器、分割模型以及多模态理解与视觉问答（Visual Question Answering）模块的效率与性能。利用Habitat-Matterport 3D数据集的$\textit{val-mini}$和$\textit{val}$划分，我们在VRAM有限的台式机上进行了实验。我们提出了一种解决方案，在无需显著增加成功权重路径长度损失的情况下，相较于VLFM BLIP-2基线实现了+1.55%的成功率提升，同时所需的视频内存减少了$\textbf{2.3倍}$。我们的研究结果为平衡模型性能与计算效率提供了洞见，并为资源受限环境下的有效部署策略提供了建议。
|
English: Many existing data mining algorithms use feature values directly in their
model, making them sensitive to units/scales used to measure/represent data.
Pre-processing of data based on rank transformation has been suggested as a
potential solution to overcome this issue. However, the resulting data after
pre-processing with rank transformation is uniformly distributed, which may not
be very useful in many data mining applications. In this paper, we present a
better and effective alternative based on ranks over multiple sub-samples of
data. We call the proposed pre-processing technique as ARES | Average Rank over
an Ensemble of Sub-samples. Our empirical results of widely used data mining
algorithms for classification and anomaly detection in a wide range of data
sets suggest that ARES results in more consistent task specific? outcome across
various algorithms and data sets. In addition to this, it results in better or
competitive outcome most of the time compared to the most widely used min-max
normalisation and the traditional rank transformation.
Chinese: 许多现有的数据挖掘算法直接使用特征值在其模型中，这使得它们对用于测量/表示数据的单位/尺度敏感。基于秩变换的数据预处理已被建议作为一种潜在的解决方案来克服这个问题。然而，使用秩变换进行预处理后的数据是均匀分布的，这在许多数据挖掘应用中可能并不那么有用。在本文中，我们提出了一种基于数据多个子样本的秩的更好且有效的替代方案。我们将所提出的预处理技术称为ARES | 子样本集合的平均秩。我们在各种数据集上对分类和异常检测的广泛使用的数据挖掘算法进行的经验结果表明，ARES在各种算法和数据集上产生了更一致的特定任务结果。除此之外，与最广泛使用的min-max归一化和传统秩变换相比，它大多数时候能产生更好或具有竞争力的结果。
|
English: Out-of-time-order correlators (OTOCs) that capture maximally chaotic
properties of a black hole are determined by scattering processes near the
horizon. This prompts the question to what extent OTOCs display chaotic
behaviour in horizonless microstate geometries. This question is complicated by
the fact that Lyapunov growth of OTOCs requires nonzero temperature, whereas
constructions of microstate geometries have been mostly restricted to extremal
black holes.
In this paper, we compute OTOCs for a class of extremal black holes, namely
maximally rotating BTZ black holes, and show that on average they display "slow
scrambling", characterized by cubic (rather than exponential) growth.
Superposed on this average power-law growth is a sawtooth pattern, whose steep
parts correspond to brief periods of Lyapunov growth associated to the nonzero
temperature of the right-moving degrees of freedom in a dual conformal field
theory.
Next we study the extent to which these OTOCs are modified in certain
"superstrata", horizonless microstate geometries corresponding to these black
holes. Rather than an infinite throat ending on a horizon, these geometries
have a very deep but finite throat ending in a cap. We find that the
superstrata display the same slow scrambling as maximally rotating BTZ black
holes, except that for large enough time intervals the growth of the OTOC is
cut off by effects related to the cap region, some of which we evaluate
explicitly.
Chinese: 能够捕捉黑洞最大混沌特性的时序关联函数（OTOCs）由视界附近的散射过程决定。这引发了一个问题：OTOCs在无视界微观态几何中表现出混沌行为到何种程度。这个问题因以下事实而变得复杂：OTOCs的李雅普诺夫增长需要非零温度，而微观态几何的构建大多局限于极端黑洞。
在本文中，我们计算了一类极端黑洞的OTOCs，即最大旋转BTZ黑洞，并表明它们平均上表现出“缓慢搅动”，其特征是三次方（而非指数）增长。在这个平均幂律增长之上叠加着一个锯齿状模式，其陡峭部分对应于与双亲 conformal 场论中右移自由度的非零温度相关的短暂李雅普诺夫增长时期。
接下来，我们研究这些OTOCs在特定“超层”中的变化程度，这些超层是无视界微观态几何，对应于这些黑洞。这些几何结构并非以视界为终点的无限喉管，而是以帽状结构为终点的非常深但有限的喉管。我们发现，超层与最大旋转BTZ黑洞一样表现出缓慢搅动，只是对于足够长的时间间隔，OTOC的增长会被与帽状区域相关的效应切断，其中一些效应我们进行了显式计算。
|
English: Systems with many stable configurations abound in nature, both in living and
inanimate matter. Their inherent nonlinearity and sensitivity to small
perturbations make them challenging to study, particularly in the presence of
external driving, which can alter the relative stability of different
attractors. Under such circumstances, one may ask whether any clear
relationship holds between the specific pattern of external driving and the
particular attractor states selected by a driven multistable system. To gain
insight into this question, we numerically study driven disordered mechanical
networks of bistable springs which possess a vast number of stable
configurations arising from the two stable rest lengths of each spring, thereby
capturing the essential physical properties of a broad class of multistable
systems. We find that the attractor states of driven disordered multistable
mechanical networks are fine-tuned with respect to the pattern of external
forcing to have low work absorption from it. Furthermore, we find that these
drive-specific attractor states are even more stable than expected for a given
level of work absorption. Our results suggest that the driven exploration of
the vast configuration space of these systems is biased towards states with
exceptional relationship to the driving environment, and could therefore be
used to `discover' states with desired response properties in systems with a
vast landscape of diverse configurations.
Chinese: 自然界中存在大量具有多种稳定构型的系统，既存在于生物体中，也存在于无生命物质中。这些系统的内在非线性以及对微小扰动的敏感性使得它们的研究极具挑战性，尤其是在存在外部驱动的情况下，因为外部驱动会改变不同吸引子之间的相对稳定性。在这种情况下，人们可能会问，外部驱动的特定模式与受驱动多稳系统所选的特定吸引子状态之间是否存在明确的关系。为了深入了解这个问题，我们数值研究了由双稳弹簧组成的受驱动无序机械网络，这些弹簧具有大量稳定的构型，源于每个弹簧的两个稳定平衡长度，从而捕捉了广泛多稳系统的基本物理特性。我们发现，受驱动无序多稳机械网络的吸引子状态会精细调谐外部驱动模式，以从其吸收低工作。此外，我们发现这些驱动特定的吸引子状态甚至比预期的工作吸收水平更加稳定。我们的结果表明，这些系统庞大的构型空间中的受驱动探索倾向于那些与驱动环境具有特殊关系的状态，因此可以用于在具有大量多样化构型的系统中“发现”具有所需响应特性的状态。
|
English: We investigate soliton collisions a one-parameter family of scalar field
theories in 1+1 dimensions which was first discussed by Christ and Lee. The
models have a sextic potential with three local minima, and for suitably small
values of the parameter its kinks have an internal structure in the form of two
weakly-bound subkinks. We show that for these values of the parameter kink
collisions are best understood as an independent sequence of collisions of
these subkinks, and that a static mode analysis is not enough to explain
resonant structures emerging in this model. We also emphasise the role of
radiation and oscillon formation in the collision process.
Chinese: 我们研究了Christ和Lee首次讨论的1+1维标量场理论的一个参数族中的孤子碰撞。这些模型具有一个六次势，有三个局部极小值，并且当参数取适当小的值时，其畴具有由两个弱束缚亚畴构成的内禀结构。我们证明，对于这些参数值，畴碰撞最好被理解为这些亚畴的独立碰撞序列，并且静态模分析不足以解释该模型中出现的共振结构。我们还强调了辐射和振荡子形成在碰撞过程中的作用。
|
English: We describe a semidefinite programming framework for proving upper bounds on
concrete sifting problems, and show that the Large Sieve can be interpreted as
a special case of this framework. With a small tweak, the Larger Sieve also
falls into this framework.
We compare the semidefinite approach to the linear programming approach
(i.e., the general framework of the combinatorial sieve and the Selberg sieve),
and show that it has a qualitative advantage in a toy case where the primes are
completely independent from each other. No new sieve-theoretic bounds are
proved.
Chinese: 我们描述了一个半定规划框架，用于证明具体筛选问题的上界，并表明大筛法可以解释为该框架的特殊情况。经过轻微调整，大筛法也属于这个框架。
我们比较了半定规划方法与线性规划方法（即组合筛法和塞尔伯格筛法的一般框架），并表明在素数完全相互独立的小案例中，它具有定性优势。没有证明新的筛法理论界限。
|
English: The variational cluster approximation is used to study the isotropic
triangular-lattice Hubbard model at half filling, taking into account the
nearest-neighbor ($t_1$) and next-nearest-neighbor ($t_2$) hopping parameters
for magnetic frustrations. We determine the ground-state phase diagram of the
model. In the strong correlation regime, the 120$^\circ$ N\'eel and stripe
ordered phases appear, and a nonmagnetic insulating phase emerges in between.
In the intermediate correlation regime, the nonmagnetic insulating phase
expands to a wider parameter region, which goes into a paramagnetic metallic
phase in the weak correlation regime. The critical phase boundary of the Mott
metal-insulator transition is discussed in terms of the van Hove singularity
evident in the calculated density of states and single-particle spectral
function.
Chinese: 变分簇近似被用来研究半填充时各向同性的三角形晶格Hubbard模型，考虑了最近邻（$t_1$）和次近邻（$t_2$）跃迁参数以描述磁性反铁磁性。我们确定了该模型的基态相图。在强关联区域，出现了120° Néel序和条带序相，两者之间出现了一种非磁性绝缘相。在中等关联区域，非磁性绝缘相扩展到更宽的参数区域，在弱关联区域转变为顺磁性金属相。Mott绝缘体-金属转变的临界相边界通过计算态密度和单粒子谱函数中明显的van Hove奇点来讨论。
|
English: This paper develops a nonparametric model that represents how sequences of
outcomes and treatment choices influence one another in a dynamic manner. In
this setting, we are interested in identifying the average outcome for
individuals in each period, had a particular treatment sequence been assigned.
The identification of this quantity allows us to identify the average treatment
effects (ATE's) and the ATE's on transitions, as well as the optimal treatment
regimes, namely, the regimes that maximize the (weighted) sum of the average
potential outcomes, possibly less the cost of the treatments. The main
contribution of this paper is to relax the sequential randomization assumption
widely used in the biostatistics literature by introducing a flexible
choice-theoretic framework for a sequence of endogenous treatments. We show
that the parameters of interest are identified under each period's two-way
exclusion restriction, i.e., with instruments excluded from the
outcome-determining process and other exogenous variables excluded from the
treatment-selection process. We also consider partial identification in the
case where the latter variables are not available. Lastly, we extend our
results to a setting where treatments do not appear in every period.
Chinese: 本文开发了一个非参数模型，该模型描述了结果序列和治疗选择如何以动态方式相互影响。在此背景下，我们感兴趣的是确定在给定特定治疗序列的情况下，每个时期个体的平均结果。这一数量的识别使我们能够识别平均治疗效应（ATEs）和ATEs在过渡中的作用，以及最优治疗制度，即最大化（加权）平均潜在结果总和的制度，可能减去治疗成本。本文的主要贡献是通过引入一个灵活的选择理论框架，用于内生治疗序列，放松了生物统计学文献中广泛使用的顺序随机化假设。我们表明，在每一期的双向排除限制下，即通过排除决定结果的过程中的工具变量和其他排除在治疗选择过程之外的外生变量，可以识别感兴趣的参数。我们还考虑了在后一种变量不可用的情况下的部分识别。最后，我们将我们的结果扩展到治疗在每个时期都不出现的情况。
|
English: We show that time-reflection symmetry in periodically driven (Floquet)
quantum systems enables an inherently nonequilibrium phenomenon structurally
similar to quantum-mechanical sypersymmetry. In particular, we find Floquet
analogues of the Witten index that place lower bounds on the degeneracies of
states with quasienergies $0$ and $\pi$. Moreover, we show that in some cases
time reflection symmetry can also interchange fermions and bosons, leading to
fermion/boson pairs with opposite quasienergy. We provide a simple class of
disordered, interacting, and ergodic Floquet models with an exponentially large
number of states at quasienergies $0$ and $\pi$, which are robust as long as
the time-reflection symmetry is preserved. Floquet supersymmetry manifests
itself in the evolution of certain local observables as a period-doubling
effect with dramatic finite-size scaling, providing a clear signature for
experiments.
Chinese: 我们证明了在周期驱动（Floquet）量子系统中，时间反射对称性能够产生一种本质上非平衡的现象，其结构上类似于量子力学的超对称性。特别是，我们发现Witten指标的Floquet类似物，这些指标对准能$0$和$\pi$的态的简并度设置了下限。此外，我们表明在某些情况下，时间反射对称性也可以交换费米子和玻色子，导致具有相反准能的费米子/玻色子对。我们提供了一类无序、相互作用和遍历的Floquet模型，这些模型在准能$0$和$\pi$处具有指数级数量的态，只要时间反射对称性得到保持，这些态就是鲁棒的。Floquet超对称性体现在某些局部可观测量随时间的演化中，表现为具有剧烈有限尺寸标度效应的倍周期效应，为实验提供了一个明确的特征。
|
English: Ultrathin iron oxide films epitaxially grown on the (111)- and
(0001)-oriented metal single crystal supports exhibit unique electronic,
catalytic and magnetic properties not observed for the corresponding bulk
oxides. These properties originate mainly from the presence of Moir\'e
superstructures which, in turn, disqualify ultrathin films as model systems
imitating bulk materials. We present a route for the preparation of a
close-packed Moir\'e-free ultrathin iron oxide film, namely FeO(111) on
Ag(111). Experimental scanning tunneling microscopy (STM), low energy electron
diffraction (LEED) and x-ray photoelectron spectroscopy (XPS) results confirm
perfect structural order in the film. Density functional theory (DFT)-based
calculations suggest full relaxation of the oxide layer that adopts the atomic
lattice of the crystalline support and exhibits properties similar to those of
a free-standing FeO. The results open new pathways for model-type studies of
electronic, catalytic and magnetic properties of fully-relaxed iron oxide films
and related systems.
Chinese: 在(111)和(0001)取向的金属单晶衬底上外延生长的超薄氧化铁薄膜展现出独特的电子、催化和磁性能，这些性能在相应的块体氧化物中并未观察到。这些性能主要源于莫尔超结构的存在，而这反过来又使得超薄薄膜不能作为模拟块体材料的模型系统。我们提出了一种制备紧密堆积、无莫尔超结构的超薄氧化铁薄膜的方法，即Ag(111)上的FeO(111)。实验扫描隧道显微镜(STM)、低能电子衍射(LEED)和X射线光电子能谱(XPS)结果表明，薄膜中具有完美的结构有序性。基于密度泛函理论(DFT)的计算表明，氧化物层完全弛豫，其采用结晶衬底的原子晶格，并展现出与独立FeO相似的特性。这些结果为研究完全弛豫的氧化铁薄膜及其相关系统的电子、催化和磁性能开辟了新的途径。
|
English: We present a two-layer fully connected neuromorphic system based on a
thin-film transistor (TFT)-type NOR flash memory array with multiple
postsynaptic (POST) neurons. Unsupervised online learning by
spike-timing-dependent plasticity (STDP) on the binary MNIST handwritten
datasets is implemented, and its recognition result is determined by measuring
firing rate of POST neurons. Using a proposed learning scheme, we investigate
the impact of the number of POST neurons in terms of recognition rate. In this
neuromorphic system, lateral inhibition function and homeostatic property are
exploited for competitive learning of multiple POST neurons. The simulation
results demonstrate unsupervised online learning of the full black-and-white
MNIST handwritten digits by STDP, which indicates the performance of pattern
recognition and classification without preprocessing of input patterns.
Chinese: 我们提出了一种基于薄膜晶体管（TFT）型NOR闪存阵列和多个突触后（POST）神经元的两层全连接神经形态系统。在二进制MNIST手写数据集上，通过时间依赖性突触可塑性（STDP）实现了无监督的在线学习，其识别结果通过测量POST神经元的放电率来确定。使用提出的学习方案，我们研究了POST神经元数量对识别率的影响。在这个神经形态系统中，通过侧抑制功能和稳态特性，实现了多个POST神经元的竞争学习。仿真结果表明，通过STDP实现了对全黑白MNIST手写数字的无监督在线学习，这表明了在无需预处理输入模式的情况下，模式识别和分类的性能。
|
English: In this paper, we aim to develop a method for automatically detecting and
tracking topics in broadcast news. We present a hierarchical And-Or graph (AOG)
to jointly represent the latent structure of both texts and visuals. The AOG
embeds a context sensitive grammar that can describe the hierarchical
composition of news topics by semantic elements about people involved, related
places and what happened, and model contextual relationships between elements
in the hierarchy. We detect news topics through a cluster sampling process
which groups stories about closely related events. Swendsen-Wang Cuts (SWC), an
effective cluster sampling algorithm, is adopted for traversing the solution
space and obtaining optimal clustering solutions by maximizing a Bayesian
posterior probability. Topics are tracked to deal with the continuously updated
news streams. We generate topic trajectories to show how topics emerge, evolve
and disappear over time. The experimental results show that our method can
explicitly describe the textual and visual data in news videos and produce
meaningful topic trajectories. Our method achieves superior performance
compared to state-of-the-art methods on both a public dataset Reuters-21578 and
a self-collected dataset named UCLA Broadcast News Dataset.
Chinese: 在本文中，我们旨在开发一种自动检测和追踪广播新闻主题的方法。我们提出了一种与或图 (AOG) 来联合表示文本和视觉的潜在结构。该 AOG 嵌入了一种上下文敏感语法，能够通过涉及的人物、相关地点和发生的事件等语义元素描述新闻主题的层次结构，并建模层次结构中元素之间的上下文关系。我们通过聚类采样过程检测新闻主题，将关于密切相关事件的故事分组。采用有效的聚类采样算法 Swendsen-Wang 割分 (SWC) 遍历解空间，并通过最大化贝叶斯后验概率获得最优聚类解。我们追踪主题以处理持续更新的新闻流。我们生成主题轨迹以展示主题随时间如何出现、演化和消失。实验结果表明，我们的方法能够明确描述新闻视频中的文本和视觉数据，并产生有意义的主题轨迹。与最先进方法相比，我们的方法在公共数据集 Reuters-21578 和自收集数据集 UCLA Broadcast News Dataset 上均取得了优异性能。
|
English: The dramatic increase in the use of social media platforms for information
sharing has also fueled a steep growth in online abuse. A simple yet effective
way of abusing individuals or communities is by creating memes, which often
integrate an image with a short piece of text layered on top of it. Such
harmful elements are in rampant use and are a threat to online safety. Hence it
is necessary to develop efficient models to detect and flag abusive memes. The
problem becomes more challenging in a low-resource setting (e.g., Bengali
memes, i.e., images with Bengali text embedded on it) because of the absence of
benchmark datasets on which AI models could be trained. In this paper we bridge
this gap by building a Bengali meme dataset. To setup an effective benchmark we
implement several baseline models for classifying abusive memes using this
dataset. We observe that multimodal models that use both textual and visual
information outperform unimodal models. Our best-performing model achieves a
macro F1 score of 70.51. Finally, we perform a qualitative error analysis of
the misclassified memes of the best-performing text-based, image-based and
multimodal models.
Chinese: 社交媒体平台在信息分享方面的使用急剧增加，也助长了网络暴力的快速增长。一种简单但有效的方式是通过创建表情包来虐待个人或社区，这些表情包通常将一张图片与叠加在图片上的简短文字结合起来。这些有害元素被广泛使用，并威胁到网络安全。因此，有必要开发高效的模型来检测和标记虐待性表情包。在低资源环境下（例如孟加拉语表情包，即嵌入孟加拉语文本的图片），由于缺乏可用于训练人工智能模型的基准数据集，这个问题变得更加具有挑战性。在本文中，我们通过构建一个孟加拉语表情包数据集来填补这一空白。为了建立一个有效的基准，我们使用这个数据集实现了几个基线模型来对虐待性表情包进行分类。我们观察到，使用文本和视觉信息的多模态模型优于单模态模型。我们表现最佳的模型达到了70.51的宏F1分数。最后，我们对表现最佳的基于文本、基于图像和多模态模型的错误分类表情包进行了定性的错误分析。
|
English: By direct comparison between experiment and theory, we show how the classical
noise on a multi-state atom laser beam increases with increasing flux. The
trade off between classical noise and flux is an important consideration in
precision interferometric measurement. We use periodic 10 microsecond
radio-frequency pulses to couple atoms out of an F=2 87Rb Bose-Einstein
condensate. The resulting atom laser beam has suprising structure which is
explained using three dimensional simulations of the five state
Gross-Pitaevskii equations.
Chinese: 通过实验与理论的直接比较，我们展示了多态原子激光束上的经典噪声如何随着通量的增加而增加。经典噪声与通量之间的权衡是精密干涉测量中的一个重要考虑因素。我们使用周期性的10微秒射频脉冲将原子从F=2的87Rb玻色-爱因斯坦凝聚态中耦合出来。由此产生的原子激光束具有令人惊讶的结构，该结构通过五个状态的Gross-Pitaevskii方程的三维模拟得到解释。
|
English: We study the longitudinal sound propagation in the electronic nematic Fermi
liquid where the Fermi surface is distorted due to the spontaneously broken
rotational symmetry. The behavior of the sound wave in the nematic ordered
state is dramatically different from that in the isotropic Fermi liquid. The
collective modes associated with the fluctuations of the Fermi surface
distortion in the nematic Fermi liquid leads to the strong and anisotropic
damping of the sound wave. The relevance of the nematic Fermi liquid in doped
Mott insulator is discussed.
Chinese: 我们研究了电子向列相费米液体中的纵向声波传播，其中费米面由于自发破缺的旋转对称性而变形。在向列有序状态下的声波行为与各向同性费米液体中的行为有显著不同。与向列费米液体中费米面变形涨落相关的集体模式导致声波强烈且各向异性的阻尼。讨论了掺杂莫特绝缘体中向列费米液体的相关性。
|
English: Given a sequence ${\bf g}: g_0,\ldots, g_{m}$, in a finite group $G$ with
$g_0=1_G$, let ${\bf \bar g}: \bar g_0,\ldots, \bar g_{m}$, be the sequence
defined by $\bar g_0=1_G$ and $\bar g_i=g_{i-1}^{-1}g_i$ for $1\leq i \leq m$.
We say that $G$ is doubly sequenceable if there exists a sequence ${\bf g}$ in
$G$ such that every element of $G$ appears exactly twice in each of ${\bf g}$
and ${\bf \bar g}$. If a group $G$ is abelian, odd, sequenceable,
R-sequenceable, or terraceable, then $G$ is doubly sequenceable. In this paper,
we show that if $N$ is an odd or sequenceable group and $H$ is an abelian
group, then $N \times H$ is doubly sequenceable.
Chinese: 给定一个有限群 $G$ 中的序列 ${\bf g}: g_0,\ldots, g_{m}$，其中 $g_0=1_G$，令 ${\bf \bar g}: \bar g_0,\ldots, \bar g_{m}$ 为由 $\bar g_0=1_G$ 和 $\bar g_i=g_{i-1}^{-1}g_i$ 对于 $1\leq i \leq m$ 定义的序列。
我们说 $G$ 是双序列可列的，如果存在一个 $G$ 中的序列 ${\bf g}$，使得 $G$ 的每个元素在每个 ${\bf g}$ 和 ${\bf \bar g}$ 中恰好出现两次。如果一个群 $G$ 是阿贝尔群、奇数群、可序列群、R-可序列群或平台群，那么 $G$ 是双序列可列的。在这篇论文中，我们证明如果 $N$ 是一个奇数群或可序列群，且 $H$ 是一个阿贝尔群，那么 $N \times H$ 是双序列可列的。
|
English: Today's systems are overwhelmingly designed to move data to computation. This
design choice goes directly against at least three key trends in systems that
cause performance, scalability and energy bottlenecks: (1) data access from
memory is already a key bottleneck as applications become more data-intensive
and memory bandwidth and energy do not scale well, (2) energy consumption is a
key constraint in especially mobile and server systems, (3) data movement is
very expensive in terms of bandwidth, energy and latency, much more so than
computation.
At the same time, conventional memory technology is facing many scaling
challenges in terms of reliability, energy, and performance. As a result,
memory system architects are open to organizing memory in different ways and
making it more intelligent, at the expense of higher cost. The emergence of
3D-stacked memory plus logic as well as the adoption of error correcting codes
inside DRAM chips, and the necessity for designing new solutions to serious
reliability and security issues, such as the RowHammer phenomenon, are an
evidence of this trend.
Recent research aims to practically enable computation close to data. We
discuss at least two promising directions for processing-in-memory (PIM): (1)
performing massively-parallel bulk operations in memory by exploiting the
analog operational properties of DRAM, with low-cost changes, (2) exploiting
the logic layer in 3D-stacked memory technology to accelerate important
data-intensive applications. In both approaches, we describe and tackle
relevant cross-layer research, design, and adoption challenges in devices,
architecture, systems, and programming models. Our focus is on the development
of in-memory processing designs that can be adopted in real computing platforms
at low cost.
Chinese: 今天的系统绝大多数都是为了将数据移动到计算中而设计的。这种设计选择与至少三个导致性能、可扩展性和能源瓶颈的关键趋势直接相悖：(1) 随着应用变得更加数据密集，内存带宽和能源无法很好地扩展，内存中的数据访问已经成为一个关键瓶颈；(2) 能耗是移动和服务器系统中的关键约束；(3) 数据移动在带宽、能源和延迟方面代价高昂，远高于计算。
同时，传统的内存技术在可靠性、能源和性能方面面临着许多扩展挑战。因此，内存系统架构师们愿意以更高的成本为代价，以不同的方式组织内存并使其更加智能。3D堆叠内存加上逻辑的兴起，以及在DRAM芯片内采用纠错码，以及设计新解决方案来解决严重可靠性问题和安全问题（如RowHammer现象）的必要性，都是这一趋势的证明。
最近的研究旨在使计算接近数据成为可能。我们讨论了至少两个处理在内存（PIM）的可行方向：(1) 通过利用DRAM的模拟操作特性，以低成本的方式在内存中执行大规模并行批量操作；(2) 利用3D堆叠内存技术中的逻辑层来加速重要的数据密集型应用。在这两种方法中，我们描述并解决了设备、架构、系统和编程模型中的相关跨层研究、设计和采用挑战。我们的重点是开发可以在实际计算平台上以低成本采用的内存处理设计。
|
English: We investigate ultrafast harmonic generation (HG) in Si:B, driven by intense
pump pulses with fields reaching ~100 kV/cm and a carrier frequency of 300 GHz,
at 4 K and 300 K, both experimentally and theoretically. We report several
novel findings concerning the nonlinear charge carrier dynamics in intense
sub-THz fields. (i) Harmonics of order up to n=9 are observed at room
temperature, while at low temperature we can resolve harmonics reaching even
n=13. The susceptibility per charge carrier at moderate field strength is as
high as for charge carriers in graphene, considered to be one of the materials
with the strongest sub-THz nonlinear response. (ii) For T=300 K, where the
charge carriers bound to acceptors are fully thermally ionized into the valence
subbands, the susceptibility values decrease with increasing field strength.
Simulations incorporating multi-valence-band Monte-Carlo and
finite-difference-time-domain (FDTD) propagation show that here, the HG process
becomes increasingly dominated by energy-dependent scattering rates over the
contribution from band non-parabolicity, due to the onset of optical-phonon
emission, which ultimately leads to the saturation at high fields. (iii) At T=4
K, where the majority of charges are bound to acceptors, we observe a drastic
rise of the HG yields for internal pump fields of 30 kV/cm, as one reaches the
threshold for tunnel ionization. We disentangle the HG contributions in this
case into contributions from the initial 'generational'- and subsequent
band-nonlinearities, and show that scattering seriously degrades any coherent
recollision during the subsequent oscillation of the holes.
Chinese: 我们实验和理论地研究了在4 K和300 K下，由强泵浦脉冲（场强达到~100 kV/cm，载波频率为300 GHz）驱动的Si:B中的超快谐波生成（HG）。我们报告了关于强亚太赫兹场中非线性载流子动力学的一些新发现。（i）在室温下观察到高达n=9阶的谐波，而在低温下我们可以解析出甚至达到n=13的谐波。在中等场强下，每载流子的磁化率高达石墨烯中的载流子，石墨烯被认为是最强亚太赫兹非线性响应的材料之一。（ii）对于T=300 K，此时与受主结合的载流子完全热电离进入价带子带，磁化率值随着场强的增加而降低。结合多价带蒙特卡洛和有限差分时域（FDTD）传播的模拟显示，在这里，由于光学声子发射的开始，谐波生成过程越来越受能量相关的散射率的影响，而不仅仅是由于能带非抛物性的贡献，这最终导致高场强下的饱和。（iii）在T=4 K时，此时大多数电荷都与受主结合，我们观察到在内部泵浦场为30 kV/cm时，谐波生成产率急剧上升，因为此时达到隧道电离的阈值。我们将此情况下的谐波生成贡献分解为初始“生成”贡献和随后的能带非线性贡献，并表明散射严重地破坏了后续空穴振荡期间的任何相干重新碰撞。
|
English: In this paper, we study a very general type of online network design problem,
and generalize two different previous algorithms, one for an online network
design problem due to Berman and Coulston [4] and one for (offline) general
network design problems due to Goemans and Williamson [9]; we give an O(log
k)-competitive algorithm, where k is the number of nodes that must be
connected. We also consider a further generalization of the problem that allows
us to pay penalties in exchange for violating connectivity constraints; we give
an online O(log k)-competitive algorithm for this case as well.
Chinese: 在这篇论文中，我们研究了一种非常通用的在线网络设计问题，并推广了两种不同的先前算法，一种是由Berman和Coulston提出的在线网络设计问题算法[4]，另一种是由Goemans和Williamson提出的（离线）通用网络设计问题算法[9]；我们给出了一种O(log k)竞争算法，其中k是需要连接的节点数。我们还考虑了问题的进一步推广，这使得我们可以通过违反连接约束来支付罚金；对于这种情况，我们也给出了一种在线O(log k)竞争算法。
|
English: We study a confined system of Dirac fermions in the presence of inhomogeneous
magnetic field. Splitting the system into different regions, we determine their
corresponding energy spectrum solutions. We underline their physical properties
by considering the conservation energy where some interesting relations are
obtained. These are used to discuss the reflexion and transmission coefficients
for Dirac fermions and check the probability condition for different cases. We
generalize the obtained results to a system with gap and make some analysis.
After evaluating the current-carrying states, we analyze the Klein paradox and
report interesting discussions.
Chinese: 我们研究在非均匀磁场存在下的一维狄拉克费米子约束系统。将系统划分为不同区域，我们确定了它们的相应能谱解。通过考虑能量守恒，我们强调了它们的物理性质，并得到了一些有趣的关系。这些关系用于讨论狄拉克费米子的反射和透射系数，并验证不同情况下的概率条件。我们将所得结果推广到带隙系统并进行分析。在评估载流子态后，我们分析了克劳修斯悖论并报道了相关讨论。
|
English: Intrinsic, in-plane anisotropy of electrical resistivity was studied on
mechanically detwinned single crystals of SrFe$_2$As$_2$ above and below the
temperature of the coupled structural/magnetic transition, $T_{\textrm{TO}}$.
Resistivity is smaller for electrical current flow along the orthorhombic $a_o$
direction (direction of antiferromagnetically alternating magnetic moments) and
is larger for transport along the $b_o$ direction (direction of ferromagnetic
chains), which is similar to CaFe$_2$As$_2$ and BaFe$_2$As$_2$ compounds. A
strongly first order structural transition in SrFe$_2$As$_2$ was confirmed by
high-energy x-ray measurements, with the transition temperature, and character
unaffected by moderate strain. For small strain levels, which are just
sufficient to detwin the sample, we find a negligible effect on the resistivity
above $T_{\textrm{TO}}$. With the increase of strain, the resistivity
anisotropy starts to develop above $T_{\textrm{TO}}$, clearly showing the
relation of anisotropy to an anomalously strong response to strain. Our study
suggests that electronic nematicity cannot be observed in the FeAs based
compounds in which the structural transition is strongly first order.
Chinese: 在高于和低于耦合结构/磁相变温度 $T_{\textrm{TO}}$ 的 SrFe$_2$As$_2$ 机械去孪晶单晶上研究了电导率的平面各向异性。当电流沿正交 $a_o$ 方向（反铁磁交替磁矩的方向）流动时，电导率较小，而沿 $b_o$ 方向（铁磁链的方向）传输时，电导率较大，这与 CaFe$_2$As$_2$ 和 BaFe$_2$As$_2$ 化合物相似。通过高能X射线测量，证实了 SrFe$_2$As$_2$ 中存在强烈的一级结构相变，其相变温度和特征不受中等应变的影响。对于刚好足以去孪晶的微小应变水平，我们发现对 $T_{\textrm{TO}}$ 以上的电导率影响可以忽略不计。随着应变的增加，电导率各向异性在 $T_{\textrm{TO}}$ 以上开始发展，清楚地显示了各向异性与异常强烈的应变响应之间的关系。我们的研究表明，在结构相变强烈为一级的结构转变的 FeAs 基化合物中，不能观察到电子向列性。
|
English: In this paper we found the parton densities at high energies. Their
expressions stems from our attempts to reconcile the exact solution to the
Balitsky-Kovchegov (BK) equation, which describes the rare fluctuation in the
dipole-target scattering, with the fact that this equation sums the 'fan'
Pomeron diagrams. Using these densities we can calculate the contributions of
large Pomeron loops to dipole-dipole scattering at high energies. We detected
that the scattering matrix for this process has the same suppression as was
predicted by Iancu and Mueller from their estimates of the 'rare' fluctuation
in QCD.
Applying the Abramovsky,Gribov and Kancheli cutting rules we found that the
produced gluons are distributed accordingly the KNO (Koba, Nielsen and Olesen)
law which leads to the entropy $S_E = \ln(x G(x,Q^2))$. $xG$ has to be in the
saturation region at high energies.
Chinese: 在本文中，我们发现了高能下的部分子密度。它们的表达式源于我们试图将Balitsky-Kovchegov (BK) 方程的精确解——该方程描述了二极子-靶散射中的稀有涨落——与该方程对“扇形”Pomeron图求和这一事实相协调的努力。利用这些密度，我们可以计算高能下大Pomeron环对二极子-二极子散射的贡献。我们发现，该过程的散射矩阵具有与Iancu和Mueller根据他们对QCD中“稀有”涨落的估计所预测的相同抑制效应。应用Abramovsky、Gribov和Kancheli的切割规则，我们发现产生的胶子按照KNO（Koba、Nielsen和Olesen）定律分布，这导致了熵 $S_E = \ln(x G(x,Q^2))$。$xG$ 在高能下必须处于饱和区域。
|
English: In this article, we introduce the method of urban association rules and its
uses for extracting frequently appearing combinations of stores that are
visited together to characterize shoppers' behaviors. The Apriori algorithm is
used to extract the association rules (i.e., if -> result) from customer
transaction datasets in a market-basket analysis. An application to our
large-scale and anonymized bank card transaction dataset enables us to output
linked trips for shopping all over the city: the method enables us to predict
the other shops most likely to be visited by a customer given a particular shop
that was already visited as an input. In addition, our methodology can consider
all transaction activities conducted by customers for a whole city in addition
to the location of stores dispersed in the city. This approach enables us to
uncover not only simple linked trips such as transition movements between
stores but also the edge weight for each linked trip in the specific district.
Thus, the proposed methodology can complement conventional research methods.
Enhancing understanding of people's shopping behaviors could be useful for city
authorities and urban practitioners for effective urban management. The results
also help individual retailers to rearrange their services by accommodating the
needs of their customers' habits to enhance their shopping experience.
Chinese: 在本文中，我们介绍了城市关联规则的方法及其应用，用于从一起访问的商店的频繁出现的组合中提取顾客行为特征。Apriori算法被用来从市场篮子分析的顾客交易数据集中提取关联规则（即，如果 -> 结果）。在我们的大规模匿名银行交易数据集上的应用使我们能够输出全城购物的连锁旅行：该方法使我们能够预测给定一个已经访问过的特定商店作为输入，最有可能被访问的其他商店。此外，我们的方法还可以考虑顾客在全城范围内开展的所有交易活动，而不仅仅是城市中分散的商店的位置。这种方法使我们能够不仅发现简单的连锁旅行，如商店之间的过渡移动，还能发现特定区域内每条连锁旅行的边权重。因此，所提出的方法论可以补充传统的研究方法。增强对人们购物行为的了解对城市当局和城市规划者进行有效的城市管理是有益的。结果也有助于个体零售商根据顾客习惯调整服务安排，以提升他们的购物体验。
|
English: In this work we demonstrate for an experimental system, that exhibits the
Lorenz butterfly attractor behavior, that perfect chaotic phase synchronization
cannot be achieved in systems with an unbounded distribution of intrinsic time
scales. Instead, imperfect phase synchronization is characterized by the
occurrence of phase slips, associated to epochs of time during which the
chaotic oscillator exhibits a slower time scale. Interestingly, during phase
slips the chaotic oscillator keeps in sync with the drive, but with a different
locking ratio.
Chinese: 在这项工作中，我们证明了一个实验系统，该系统表现出洛伦兹蝴蝶吸引子行为，在具有无界分布的内禀时间尺度的系统中，无法实现完美的混沌相位同步。相反，不完美的相位同步以相位滑移为特征，这些相位滑移与混沌振荡器表现出较慢时间尺度的时期相关。有趣的是，在相位滑移期间，混沌振荡器仍然与驱动保持同步，但锁定比不同。
|
English: On the basis of the Carter-Israel conjecture, today we believe that some
compact and massive objects in the Galaxy and in the Universe are Kerr black
holes. However, this idea cannot yet be confirmed by observations. We can
currently obtain reliable estimates of the masses of these objects, but we do
not know if the space-time around them is described by the Kerr metric and if
they have an event horizon. A fundamental limit for a Kerr black hole is the
Kerr bound $|a_*| \le 1$. Here I discuss some astrophysical implications
associated with the violation of this bound, which can thus be used to test the
Carter-Israel conjecture.
Chinese: 基于卡特-以色列猜想，今天我们有理由相信，银河系和宇宙中的一些紧凑且质量巨大的天体是克尔黑洞。然而，这一观点尚未得到观测的证实。我们目前能够对这些物体的质量做出可靠估计，但我们不知道它们周围的时空是否由克尔度规描述，也不知道它们是否具有事件视界。对于克尔黑洞来说，一个基本极限是克尔界限 $|a_*| \le 1$。在这里，我将讨论与这一界限的违反相关的若干天文物理含义，这可以用来检验卡特-以色列猜想。
|
English: The Beamforming Elevated Array for COsmic Neutrinos (BEACON) is a planned
neutrino telescope designed to detect radio emission from upgoing air showers
generated by ultrahigh energy tau neutrino interactions in the Earth. This
detection mechanism provides a measurement of the tau flux of cosmic neutrinos.
We have installed an 8-channel prototype instrument at high elevation at
Barcroft Field Station, which has been running since 2018, and consists of 4
dual-polarized antennas sensitive between 30-80 MHz, whose signals are
filtered, amplified, digitized, and saved to disk using a custom data
acquisition system (DAQ). The BEACON prototype is at high elevation to maximize
effective volume and uses a directional beamforming trigger to improve
rejection of anthropogenic background noise at the trigger level. Here we
discuss the design, construction, and calibration of the BEACON prototype
instrument. We also discuss the radio frequency environment observed by the
instrument, and categorize the types of events seen by the instrument,
including a likely cosmic ray candidate event.
Chinese: 指向性增强阵列用于探测宇宙中微子（BEACON）是一个计划中的中微子望远镜，旨在探测由地球内超能级tau中微子相互作用产生的向上大气淋浴产生的无线电发射。这一探测机制为测量宇宙中微子的tau通量提供了可能。我们已在海拔较高的Barcroft野外观测站安装了8通道的原型仪器，该仪器自2018年开始运行，由4个双极化天线组成，这些天线对30-80 MHz的频段敏感，其信号通过定制的数据采集系统（DAQ）进行过滤、放大、数字化并保存在磁盘上。BEACON原型仪器的设计位于高海拔，以最大化有效体积，并使用方向性束形触发机制在触发级别上提高对人类活动背景噪声的拒绝率。在此，我们讨论了BEACON原型仪器的设计、建造和校准。我们还讨论了仪器观测到的无线电频率环境，并对仪器观测到的各类事件进行了分类，包括一个可能的宇宙射线候选事件。
|
English: Folding garments reliably and efficiently is a long standing challenge in
robotic manipulation due to the complex dynamics and high dimensional
configuration space of garments. An intuitive approach is to initially
manipulate the garment to a canonical smooth configuration before folding. In
this work, we develop SpeedFolding, a reliable and efficient bimanual system,
which given user-defined instructions as folding lines, manipulates an
initially crumpled garment to (1) a smoothed and (2) a folded configuration.
Our primary contribution is a novel neural network architecture that is able to
predict pairs of gripper poses to parameterize a diverse set of bimanual action
primitives. After learning from 4300 human-annotated and self-supervised
actions, the robot is able to fold garments from a random initial configuration
in under 120s on average with a success rate of 93%. Real-world experiments
show that the system is able to generalize to unseen garments of different
color, shape, and stiffness. While prior work achieved 3-6 Folds Per Hour
(FPH), SpeedFolding achieves 30-40 FPH.
Chinese: 在机器人操作中，由于服装的复杂动力学和高维配置空间，可靠且高效地折叠服装一直是一个长期存在的挑战。一个直观的方法是在折叠之前首先将服装操作到一个规范化的平滑配置。在这项工作中，我们开发了SpeedFolding，这是一个可靠且高效的双手操作系统，它根据用户定义的折叠线，将最初皱褶的服装操作为（1）平滑和（2）折叠的配置。我们的主要贡献是一个新颖的神经网络架构，它能够预测抓取器的姿态对，以参数化一系列多样的双手动作原语。在从4300个由人类标注和自监督的动作中学习后，机器人能够在平均不到120秒的时间内折叠服装，成功率高达93%。实际实验表明，该系统能够推广到不同颜色、形状和刚度的未见服装。虽然先前的工作实现了每小时3-6次折叠（FPH），SpeedFolding实现了每小时30-40次折叠。
|
English: We study the quantization of the corner symmetry algebra of 3d gravity, that
is the algebra of observables associated with 1d spatial boundaries. In the
continuum field theory, at the classical level, this symmetry algebra is given
by the central extension of the Poincar\'e loop algebra. At the quantum level,
we construct a discrete current algebra based on a quantum symmetry group given
by the Drinfeld double $\mathcal{D}\mathrm{SU}(2)$. Those discrete currents
depend on an integer $N$, a discreteness parameter, understood as the number of
quanta of geometry on the 1d boundary: low $N$ is the deep quantum regime,
while large $N$ should lead back to a continuum picture. We show that this
algebra satisfies two fundamental properties. First, it is compatible with the
quantum space-time picture given by the Ponzano-Regge state-sum model, which
provides discrete path integral amplitudes for 3d quantum gravity. The integer
$N$ then counts the flux lines attached to the boundary. Second, we analyse the
refinement, coarse-graining and fusion processes as $N$ changes, and we show
that the $N\rightarrow\infty$ limit is a classical limit where we recover the
Poincar\'e current algebra. Identifying such a discrete current algebra on
quantum boundaries is an important step towards understanding how conformal
field theories arise on spatial boundaries in quantized space-times such as in
loop quantum gravity.
Chinese: 我们研究了3维引力的角对称代数的量子化，即与一维空间边界相关的可观测量代数。在连续场论中，在经典层面上，这个对称代数由Poincaré环代数的中心扩展给出。在量子层面上，我们基于由Drinfeld双$\mathcal{D}\mathrm{SU}(2)$给出的量子对称群构建了一个离散电流代数。这些离散电流依赖于一个整数$N$，一个离散参数，理解为1维边界上几何量的量子数：低$N$对应于深量子态，而大$N$应该会回到连续图像。我们表明，这个代数满足两个基本性质。首先，它与由Ponzano-Regge状态和模型给出的量子时空图像相容，该模型为3维量子引力提供了离散路径积分振幅。整数$N$随后计数了附着在边界上的通量线。其次，我们分析了随着$N$的变化，细化、粗化和融合过程，并表明$N\rightarrow\infty$的极限是一个经典极限，在那里我们恢复了Poincaré电流代数。在量子边界上识别这样的离散电流代数是理解在量子时空（如环量子引力）的空间边界上如何出现共形场理论的重要一步。
|
English: We introduce a new class of Backward Stochastic Differential Equations in
which the $T$-terminal value $Y_{T}$ of the solution $(Y,Z)$ is not fixed as a
random variable, but only satisfies a weak constraint of the form
$E[\Psi(Y_{T})]\ge m$, for some (possibly random) non-decreasing map $\Psi$ and
some threshold $m$. We name them \textit{BSDEs with weak terminal condition}
and obtain a representation of the minimal time $t$-values $Y_{t}$ such that
$(Y,Z)$ is a supersolution of the BSDE with weak terminal condition. It
provides a non-Markovian BSDE formulation of the PDE characterization obtained
for Markovian stochastic target problems under controlled loss in Bouchard,
Elie and Touzi \cite{BoElTo09}. We then study the main properties of this
minimal value. In particular, we analyze its continuity and convexity with
respect to the $m$-parameter appearing in the weak terminal condition, and show
how it can be related to a dual optimal control problem in Meyer form. These
last properties generalize to a non Markovian framework previous results on
quantile hedging and hedging under loss constraints obtained in F\"{o}llmer and
Leukert \cite{FoLe99,FoLe00}, and in Bouchard, Elie and Touzi \cite{BoElTo09}.
Chinese: 我们引入一类新的向后随机微分方程，其中解 $(Y,Z)$ 的 $T$-终端值 $Y_{T}$ 并不是一个固定的随机变量，而只是满足一种弱约束形式 $E[\Psi(Y_{T})]\ge m$，其中 $\Psi$ 是某个（可能随机的）非递减映射，$m$ 是某个阈值。我们将它们命名为“具有弱终端条件的BSDEs”，并得到了 $Y_{t}$ 的最小时间值表示，使得 $(Y,Z)$ 成为具有弱终端条件的BSDE的超解。这为Bouchard、Elie和Touzi在受控损失下得到的马尔可夫随机目标问题的PDE特征提供了一个非马尔可夫BSDE公式。然后，我们研究了这个最小值的性质。特别是，我们分析了它与弱终端条件中出现的 $m$ 参数的连续性和凸性，并展示了它如何与Meyer形式的对偶最优控制问题相关联。这些最后的性质推广到了非马尔可夫框架，包括在Föllmer和Leukert \cite{FoLe99,FoLe00}以及Bouchard、Elie和Touzi \cite{BoElTo09}中获得的关于分位数对冲和在损失约束下的对冲的先前结果。
|
English: The main goal of network pruning is imposing sparsity on the neural network
by increasing the number of parameters with zero value in order to reduce the
architecture size and the computational speedup. In most of the previous
research works, sparsity is imposed stochastically without considering any
prior knowledge of the weights distribution or other internal network
characteristics. Enforcing too much sparsity may induce accuracy drop due to
the fact that a lot of important elements might have been eliminated. In this
paper, we propose Guided Attention for Sparsity Learning (GASL) to achieve (1)
model compression by having less number of elements and speed-up; (2) prevent
the accuracy drop by supervising the sparsity operation via a guided attention
mechanism and (3) introduce a generic mechanism that can be adapted for any
type of architecture; Our work is aimed at providing a framework based on
interpretable attention mechanisms for imposing structured and non-structured
sparsity in deep neural networks. For Cifar-100 experiments, we achieved the
state-of-the-art sparsity level and 2.91x speedup with competitive accuracy
compared to the best method. For MNIST and LeNet architecture we also achieved
the highest sparsity and speedup level.
Chinese: 网络剪枝的主要目标是通过对神经网络施加稀疏性，增加零值参数的数量，以减小架构大小和加速计算速度。在大多数先前的研究工作中，稀疏性是通过随机方式施加的，没有考虑权重分布或其他内部网络特征的先验知识。过度施加稀疏性可能会导致精度下降，因为很多重要元素可能已经被消除。在这篇论文中，我们提出了用于稀疏性学习的引导注意力（GASL）方法，以实现（1）通过减少元素数量和加速来压缩模型；（2）通过引导注意力机制监督稀疏性操作来防止精度下降；（3）引入一种通用的机制，该机制可以适应任何类型的架构；我们的工作旨在提供一个基于可解释注意力机制的框架，用于在深度神经网络中施加结构和非结构化的稀疏性。对于Cifar-100实验，我们实现了最先进的稀疏性水平和与最佳方法相比具有竞争力的2.91倍加速速度。对于MNIST和LeNet架构，我们也实现了最高的稀疏性和加速水平。
|
English: The ground state properties of a one-dimensional system with particle-hole
symmetry, consisting of a gate controlled dot coupled to an interacting
reservoir, are explored using the numerical DMRG method. It was previously
shown that the system's thermodynamic properties as a function of the gate
voltage in the Luttinger liquid phase are qualitatively similar to the behavior
of a non-interacting wire with an effective (renormalized) dot-lead coupling.
Here we examine the thermodynamic properties of the wire in the charge density
wave phase, and show that these properties behave quite differently. The number
of electrons in the system remains constant as a function of the gate voltage,
while the total energy becomes linear. Moreover, by tuning the gate voltage on
the dot in the charge density wave phase it is possible to drive the wire
through a first order quantum phase transition in which the population of each
site in the wire is inverted.
Chinese: 我们利用数值DMRG方法研究了一个具有粒子-空穴对称性的一维系统的基态性质，该系统包括一个受控的岛与一个相互作用的储层相耦合。之前的研究表明，在Luttinger液体相中，随着门电压的变化，系统的热力学性质与一个非相互作用的导线中有效（重整化）的岛-导线耦合的行为在定性上是相似的。在这里，我们研究了在电荷密度波相中导线的热力学性质，并展示了这些性质表现出显著不同的行为。随着门电压的变化，系统中的电子数保持不变，而总能量变为线性。更重要的是，通过在电荷密度波相中调节岛上的门电压，可以驱动导线通过一个第一阶的量子相变，在此相变中，导线中每个位点的占据数被反转。
|
English: We describe ferroelectric thin films with circular electrodes and develop a
thermodynamic theory that explains previously mysterious experiments. It is
found to be especially useful for restricted geometries such as microstructures
for which boundary conditions are well known to play an important role in
ferroelectric properties. We have explored a new switching mechanism, which
consists of an inhomogeneous rotational motion of the polarization and leads to
an extended vortex state. The vortex appearance exhibits characteristic
properties of a first-order field-induced phase transition: three critical
electric fields and the possibility of hysteresis behavior.
Chinese: 我们描述了具有圆形电极的铁电薄膜，并发展了一种热力学理论，该理论解释了先前一些神秘的实验。研究发现，该理论特别适用于限制性几何结构（如微结构），因为这些结构的边界条件众所周知对铁电特性起着重要作用。我们探索了一种新的转换机制，该机制由极化场的非均匀旋转运动组成，并导致扩展的涡旋状态。涡旋的出现表现出一级场诱导相变的特点：三个临界电场和滞后行为的可能性。
|
English: There is an especially strong need in modern large-scale data analysis to
prioritize samples for manual inspection. For example, the inspection could
target important mislabeled samples or key vulnerabilities exploitable by an
adversarial attack. In order to solve the "needle in the haystack" problem of
which samples to inspect, we develop a new scalable version of Cook's distance,
a classical statistical technique for identifying samples which unusually
strongly impact the fit of a regression model (and its downstream predictions).
In order to scale this technique up to very large and high-dimensional
datasets, we introduce a new algorithm which we call "influence sketching."
Influence sketching embeds random projections within the influence computation;
in particular, the influence score is calculated using the randomly projected
pseudo-dataset from the post-convergence Generalized Linear Model (GLM). We
validate that influence sketching can reliably and successfully discover
influential samples by applying the technique to a malware detection dataset of
over 2 million executable files, each represented with almost 100,000 features.
For example, we find that randomly deleting approximately 10% of training
samples reduces predictive accuracy only slightly from 99.47% to 99.45%,
whereas deleting the same number of samples with high influence sketch scores
reduces predictive accuracy all the way down to 90.24%. Moreover, we find that
influential samples are especially likely to be mislabeled. In the case study,
we manually inspect the most influential samples, and find that influence
sketching pointed us to new, previously unidentified pieces of malware.
Chinese: 在现代大规模数据分析中，特别需要优先考虑手动检查样本。例如，检查可以针对重要的误标记样本或可被对抗攻击利用的关键漏洞。为了解决“大海捞针”的问题，即确定哪些样本需要检查，我们开发了一种新的可扩展版本的Cook距离，这是一种经典的统计技术，用于识别对回归模型（及其下游预测）的拟合产生异常强烈影响的样本。为了将这项技术扩展到非常大的高维数据集，我们引入了一种新的算法，我们称之为“影响草图”。影响草图将随机投影嵌入到影响计算中；特别是，影响分数是通过使用从收敛后的广义线性模型（GLM）的随机投影伪数据集来计算的。我们验证了影响草图可以通过将技术应用于包含超过200万个可执行文件的恶意软件检测数据集，每个数据集几乎有10万个特征，来可靠且成功地发现具有影响力的样本。例如，我们发现随机删除大约10%的训练样本只会将预测准确性从99.47%略微降低到99.45%，而删除具有高影响草图分数的相同数量的样本会将预测准确性降低到90.24%。此外，我们发现具有影响力的样本特别可能被误标记。在案例研究中，我们手动检查了最具影响力的样本，并发现影响草图指引我们发现了新的、之前未识别的恶意软件。
|
English: We propose a new method to numerically calculate higher-order correlation
functions of primordial fluctuations generated from any early-universe
scenario. Our key-starting point is the realization that the tree-level In-In
formalism is intrinsically separable. This enables us to use modal techniques
to efficiently calculate and represent non-Gaussian shapes in a separable form
well suited to data analysis. We prove the feasibility and the accuracy of our
method by applying it to simple single-field inflationary models in which
analytical results are available, and we perform non-trivial consistency checks
like the verification of the single field consistency relation. We also point
out that the i epsilon prescription is automatically taken into account in our
method, preventing the need for ad-hoc tricks to implement it numerically.
Chinese: 我们提出了一种新的方法来数值计算由任何早期宇宙场景产生的原初扰动的更高阶相关函数。我们的关键起点是认识到树级In-In形式在本质上是可以分离的。这使得我们能够使用模态技术以高效的方式计算和表示非高斯形状，以分离的形式呈现，非常适合数据分析。我们通过将其应用于简单单场膨胀模型并验证解析结果来证明我们方法的可行性和准确性，这些模型中存在可用的解析结果，并执行了非平凡的相容性检查，如验证单场相容性关系。我们还指出，我们的方法自动考虑了i epsilon规定，从而避免了在数值实现时需要特定的技巧。
|
English: The data from the last seven experiments performed on polarized
deep--inelastic scattering on proton and neutron (or deuteron) targets have
been analyzed in search of a precise determination of the spin fraction carried
by the quarks in the nucleon. We find that this fraction can be of the size
expected from na\"{\i}ve quark model arguments, provided the gluon axial
anomaly is explicitly included and the isosinglet axial charge normalization is
fixed at a suitably low momentum scale, such that a) the running, strong
coupling constant is about unit, and b) the orbital angular momentum inside the
nucleon vanishes.
We also find that, despite the appeal of this solution of the ``nucleon spin
crisis'', a solution where the axial anomaly is absent and its effects are
traded for an appreciable strange quark polarization can not however be
excluded --- because of the limited accuracy of the data --- unless this latter
and/or the gluon polarization in the nucleon are explicitly measured.
Chinese: 对在质子和中子（或氘核）靶上进行的最近七次极化深度非弹性散射实验的数据进行了分析，旨在精确确定核子中夸克携带的自旋分数。我们发现，这一分数与简单夸克模型论点预期的规模相符，前提是明确包含胶子轴 anomaly，并将同位旋单态轴电荷归一化固定在合适的低动量尺度，使得a) 运行强耦合常数约为1，b) 核子内部的轨道角动量为零。
我们还发现，尽管这个“核子自旋危机”的解决方案颇具吸引力，但无法排除轴 anomaly 不存在且其效应被显著奇异夸克极化所替代的解决方案——因为数据精度有限——除非明确测量了后者和/或在核子中的胶子极化。
|
English: For any algebraically closed field $k$ of positive characteristic $p$ and any
non negative integer $n$ K\"ulshammer defined ideals $T\_nA^\perp$ of the
centre of a symmetric $k$-algebra $A$. We show that for derived equivalent
algebras $A$ and $B$ there is an isomorphism of the centres of $A$ and $B$
mapping $T\_nA^\perp$ to $T\_nB^\perp$ for all $n$. Recently H\'ethelyi,
Horv\'ath, K\"ulshammer and Murray showed that this holds for Morita equivalent
algebras.
Chinese: 对于任何正特征 $p$ 的代数闭域 $k$ 和任何非负整数 $n$，Külschammer 定义了对称 $k$-代数 $A$ 的中心中的理想 $T_nA^\perp$。我们证明了对于导等价代数 $A$ 和 $B$，存在一个同构，将 $A$ 和 $B$ 的中心映射到对方，对于所有 $n$，都满足 $T_nA^\perp$ 映射到 $T_nB^\perp$。最近，Héthelyi、Horváth、Külschammer 和 Murray 证明了这一点对于 Morita 等价代数也成立。
|
English: Deep reinforcement learning is a technique for solving problems in a variety
of environments, ranging from Atari video games to stock trading. This method
leverages deep neural network models to make decisions based on observations of
a given environment with the goal of maximizing a reward function that can
incorporate cost and rewards for reaching goals. With the aim of pathfinding,
reward conditions can include reaching a specified target area along with costs
for movement. In this work, multiple Deep Q-Network (DQN) agents are trained to
operate in a partially observable environment with the goal of reaching a
target zone in minimal travel time. The agent operates based on a visual
representation of its surroundings, and thus has a restricted capability to
observe the environment. A comparison between DQN, DQN-GRU, and DQN-LSTM is
performed to examine each models capabilities with two different types of
input. Through this evaluation, it is been shown that with equivalent training
and analogous model architectures, a DQN model is able to outperform its
recurrent counterparts.
Chinese: 深度强化学习是一种解决各种环境问题的技术，范围从雅达利视频游戏到股票交易。这种方法利用深度神经网络模型，根据给定环境的观察结果来做出决策，目标是最大化一个可以包含达到目标的成本和奖励的奖励函数。为了寻找路径，奖励条件可以包括到达指定目标区域以及移动成本。在本工作中，多个深度Q网络（DQN）代理被训练在部分可观察的环境中，目标是在最短的旅行时间内达到目标区域。代理根据其周围环境的视觉表示进行操作，因此其观察环境的能力有限。对DQN、DQN-GRU和DQN-LSTM进行了比较，以检查这两种不同输入类型下的每个模型的能力。通过这一评估，已经表明，在同等训练和类似模型架构的情况下，DQN模型能够超越其循环对应模型。
|
English: Structural coloration is an interference phenomenon where colors emerge when
visible light interacts with nanoscopically structured material, and has
recently become a most interesting scientific and engineering topic. However,
current structural color generation mechanisms either require thick (compared
to the wavelength) structures or lack dynamic tunability. This report proposes
a new structural color generation mechanism, that produces colors by the Fano
resonance effect on thin photonic crystal slab. We experimentally realize the
proposed idea by fabricating the samples that show resonance-induced colors
with weak dependence on the viewing angle. Finally, we show that the
resonance-induced colors can be dynamically tuned by stretching the photonic
crystal slab fabricated on an elastic substrate.
Chinese: 结构色是一种干涉现象，当可见光与纳米结构材料相互作用时，颜色就会出现，最近已成为一个最有趣的科学和工程课题。然而，目前的结构色生成机制要么需要较厚的（与波长相比）结构，要么缺乏动态可调性。本报告提出了一种新的结构色生成机制，该机制通过薄光子晶体板的范诺共振效应产生颜色。我们通过制造出表现出与视角度弱相关共振诱导颜色的样品，实验实现了所提出的想法。最后，我们展示了通过拉伸弹性基板上制造的光子晶体板，可以动态调节共振诱导的颜色。
|
English: We consider equivariant wave maps from the $(d+1)$--dimensional Minkowski
spacetime into the $d$-sphere for $d\geq 4$. We find a new explicit stable
self-similar solution and give numerical evidence that it plays the role of a
universal attractor for generic blowup. An analogous result is obtained for the
$SO(d)$ symmetric Yang-Mills field for $d\geq 6$.
Chinese: 我们考虑从$(d+1)$维闵可夫斯基时空到$d$维球面的等变波映射，其中$d\geq 4$。我们找到了一个新的显式稳定的自相似解，并给出数值证据表明它充当了通用吸引子的角色，对于一般的爆破情况。对于$d\geq 6$的$SO(d)$对称Yang-Mills场，也得到了类似的结果。
|
English: Event classification is a common task in gamma-ray astrophysics. It can be
treated with rapidly-advancing machine learning algorithms, which have the
potential to outperform traditional analysis methods. However, a major
challenge for machine learning models is extracting reliably labelled training
examples from real data. Citizen science offers a promising approach to tackle
this challenge.
We present "Muon Hunter", a citizen science project hosted on the Zooniverse
platform, where VERITAS data are classified multiple times by individual users
in order to select and parameterize muon events, a product from cosmic ray
induced showers. We use this dataset to train and validate a convolutional
neural-network model to identify muon events for use in monitoring and
calibration. The results of this work and our experience of using the
Zooniverse are presented.
Chinese: 事件分类是伽马射线天文学中的一个常见任务。它可以通过快速发展的机器学习算法进行处理，这些算法有可能超越传统的分析方法。然而，机器学习模型面临的一个主要挑战是从真实数据中提取可靠标记的训练示例。公民科学提供了一种有希望的方法来应对这一挑战。
我们介绍了“Muon Hunter”，一个在Zooniverse平台上运行的公民科学项目，其中VERITAS数据由个体用户多次分类，以选择和参数化由宇宙射线引起的淋浴产生的μ子事件。我们使用这个数据集来训练和验证一个卷积神经网络模型，以识别用于监测和校准的μ子事件。这项工作的结果以及我们在Zooniverse上的经验被展示出来。
|
English: In this paper we study M-theory compactifications on seven-dimensional
manifolds with SU(3) structure. As such manifolds naturally pick out a specific
direction, the resulting effective theory can be cast into a form which is
similar to type IIA compactifications to four dimensions. We derive the
gravitino mass matrix in four dimensions and show that for different internal
manifolds (torsion classes) the vacuum preserves either no supersymmetry, or
N=2 supersymmetry or, through spontaneous partial supersymmetry breaking, N=1
supersymmetry. For the latter case we derive the effective N=1 theory and give
explicit examples where all the moduli are stabilised without the need of
non-perturbative effects.
Chinese: 本文研究具有SU(3)结构的七维流形的M理论紧致化。由于此类流形天然选择特定方向，所得有效理论可表述为类似于IIA型四维紧致化的形式。我们推导了四维引力子质量矩阵，并证明对于不同内部流形（扭量类），真空要么保持无超对称，要么保持N=2超对称，要么通过自发部分超对称破缺保持N=1超对称。在后一种情况下，我们推导出有效N=1理论，并给出所有模均可被稳定化的具体例子，且无需非微扰效应。
|
English: We report a pore-scale numerical study of salt finger convection in porous
media, with a focus on the influence of the porosity in the non-Darcy regime,
which has received little attention in previous research. The numerical model
is based on the lattice Boltzmann method with a multiple-relaxation-time scheme
and employs an immersed boundary method to describe the fluid-solid
interaction. The simulations are conducted in a two-dimensional,
horizontally-periodic domain with an aspect ratio of 4, and the porosity is
varied from 0.7 to 1, while the solute Rayleigh number ranges from 4*10^6 to
4*10^9. Our results show that, for all explored Rayleigh number, solute
transport first enhances unexpectedly with decreasing porosity, and then
decreases when porosity is smaller than a Rayleigh number-dependent value. On
the other hand, while the flow strength decreases significantly as porosity
decreases at low Rayleigh number, it varies weakly with decreasing porosity at
high Rayleigh number and even increases counterintuitively for some porosities
at moderate Rayleigh number. Detailed analysis of the salinity and velocity
fields reveals that the fingered structures are blocked by the porous structure
and can even be destroyed when their widths are larger than the pore scale, but
become more ordered and coherent with the presence of porous media. This
combination of opposing effects explains the complex porosity-dependencies of
solute transport and flow strength. The influence of porous structure
arrangement is also examined, with stronger effects observed for smaller
porosity and higher Rayleigh number. These findings have important implications
for passive control of mass/solute transport in engineering applications.
Chinese: 我们报道了一项关于多孔介质中盐 fingering 对流的孔隙尺度数值研究，重点关注非达西状态下的孔隙率影响，这一方面在以往研究中很少受到关注。数值模型基于具有多重松弛时程的格子Boltzmann方法，并采用浸入边界法来描述流固相互作用。模拟在一个纵横比为4的二维水平周期性域中进行，孔隙率从0.7变化到1，而溶质的瑞利数范围从4×10^6变化到4×10^9。我们的结果表明，对于所有探索的瑞利数，溶质传输首先随着孔隙率的减小而意外增强，然后在孔隙率小于一个瑞利数相关的值时减少。另一方面，在低瑞利数下，随着孔隙率的减小，流动强度显著降低；但在高瑞利数下，流动强度随孔隙率减小变化微弱，甚至在中等瑞利数下对某些孔隙率出现反直觉的增加。对盐度和速度场的详细分析表明，当指状结构的宽度大于孔隙尺度时，它们会被多孔结构阻断甚至被破坏，但在多孔介质的存在下变得更加有序和连贯。这种相反效应的组合解释了溶质传输和流动强度复杂的孔隙率依赖性。还研究了多孔结构排列的影响，发现对于较小的孔隙率和较高的瑞利数，这种影响更强。这些发现对工程应用中质量/溶质传输的被动控制具有重要意义。
|
English: Vehicle platooning facilitates the partial automation of vehicles and can
significantly reduce fuel consumption. Mobile communication infrastructure
makes it possible to dynamically coordinate the formation of platoons en route.
We consider a centralized system that provides trucks with routes and speed
profiles allowing them to dynamically form platoons during their journeys. For
this to work, all possible pairs of vehicles that can platoon based on their
location, destination, and other constraints have to be identified. The
presented approach scales well to large vehicle fleets and realistic road
networks by extracting features from the transport assignments of the vehicles
and rules out a majority of possible pairs based on these features only. Merely
a small number of remaining pairs are considered in depth by a complete and
computationally expensive algorithm. This algorithm conclusively decides if
platooning is possible for a pair based on the complete data associated with
the two vehicles. We derive appropriate features for the problem and
demonstrate the effectiveness of the approach in a simulation example.
Chinese: 车辆编队促进了车辆部分自动化，并能显著减少燃料消耗。移动通信基础设施使得在路途中动态协调编队成为可能。我们考虑一个集中式系统，该系统为车辆提供路线和速度轮廓，使它们能够在旅途中动态形成编队。为了使这成为可能，必须识别出所有基于车辆位置、目的地和其他约束条件可以编队的车辆对。本文提出的方法通过从车辆运输分配中提取特征，并且仅基于这些特征排除大部分可能的车辆对，从而很好地扩展到大规模车辆车队和现实道路网络。仅考虑一小部分剩余的车辆对，并由一个完整且计算密集的算法进行深入分析。该算法基于与两辆车相关的完整数据，最终决定一对车辆是否能够编队。我们为问题衍生出适当的特征，并在一个模拟示例中展示了该方法的有效性。
|
English: Non-parametric two-sample tests based on energy distance or maximum mean
discrepancy are widely used statistical tests for comparing multivariate data
from two populations. While these tests enjoy desirable statistical properties,
their test statistics can be expensive to compute as they require the
computation of 3 distinct Euclidean distance (or kernel) matrices between
samples, where the time complexity of each of these computations (namely,
$O(n_{x}^2 p)$, $O(n_{y}^2 p)$, and $O(n_{x} n_{y} p)$) scales quadratically
with the number of samples ($n_x$, $n_y$) and linearly with the number of
variables ($p$). Since the standard permutation test requires repeated
re-computations of these expensive statistics it's application to large
datasets can become unfeasible. While several statistical approaches have been
proposed to mitigate this issue, they all sacrifice desirable statistical
properties to decrease the computational cost (e.g., trade computation speed by
a decrease in statistical power). A better computational strategy is to first
pre-compute the Euclidean distance (kernel) matrix of the concatenated data,
and then permute indexes and retrieve the corresponding elements to compute the
re-sampled statistics. While this strategy can reduce the computation cost
relative to the standard permutation test, it relies on the computation of a
larger Euclidean distance (kernel) matrix with complexity $O((n_x + n_y)^2 p)$.
In this paper, we present a novel computationally efficient permutation
algorithm which only requires the pre-computation of the 3 smaller matrices and
achieves large computational speedups without sacrificing finite-sample
validity or statistical power. We illustrate its computational gains in a
series of experiments and compare its statistical power to the current
state-of-the-art approach for balancing computational cost and statistical
performance.
Chinese: 基于能量距离或最大均差异的非参数两样本检验是广泛使用的用于比较两个总体多变量数据的统计检验。尽管这些检验具有理想的统计性质，但其检验统计量的计算成本较高，因为它们需要计算三个不同的欧几里得距离（或核）矩阵，其中每个计算的时间复杂度分别为（$O(n_{x}^2 p)$、$O(n_{y}^2 p)$和$O(n_{x} n_{y} p)$），它们相对于样本数量（$n_x$、$n_y$）呈二次方增长，相对于变量数量（$p$）呈线性增长。由于标准置换检验需要重复计算这些昂贵的统计量，因此将其应用于大型数据集可能会变得不可行。虽然已经提出了几种统计方法来缓解这一问题，但它们都牺牲了理想的统计性质以降低计算成本（例如，通过牺牲统计功效来换取计算速度的提升）。一种更好的计算策略是首先预计算合并数据集的欧几里得距离（核）矩阵，然后通过重新排列索引并检索相应元素来计算重采样的统计量。尽管这种策略相对于标准置换检验能够降低计算成本，但它依赖于计算一个更大的欧几里得距离（核）矩阵，其复杂度为$O((n_x + n_y)^2 p)$。在本论文中，我们提出了一种新颖的计算效率高的置换算法，该算法仅需要预计算三个较小的矩阵，并且能够在不牺牲有限样本有效性和统计功效的前提下实现显著的计算速度提升。我们在一系列实验中展示了其计算优势，并将其统计功效与当前计算成本和统计性能平衡的最佳方法进行了比较。
|
English: We discuss the general conditions ensuring relativistic causality in an
effective theory based on the derivative expansion. Relativistic causality
implies that the Green function vanishes in the space-like region. It is known
that a naive derivative expansion violates causality in some cases such as the
first-order relativistic dissipative hydrodynamics. We note that the Lorentz
covariance, and the equal order of time and space derivatives do not ensure
causality. We derive the general conditions for causality that should be
satisfied by any effective theories respecting special relativity. The
conditions are the followings: (i) the imaginary part of poles of the Green
function is bounded at the large momentum limit, (ii) the front velocity is
smaller than the speed of light, and (iii) the coefficient of the highest-order
time derivative does not include space derivatives.
Chinese: 我们讨论了在基于导数展开的有效理论中确保相对论因果性的通用条件。相对论因果性意味着格林函数在类时区域内消失。已知在诸如一阶相对论耗散流体动力学等情况下，简单的导数展开会违反因果性。我们指出，洛伦兹协变性和时间和空间导数的等阶性并不能保证因果性。我们推导出任何尊重狭义相对论的有效理论应满足的因果性通用条件。条件如下：（i）格林函数极点的虚部在动量极限下是有界的，（ii）前沿速度小于光速，（iii）最高阶时间导数的系数不包含空间导数。
|
English: It is widely believed that information spread on social media is a
percolation process, with parallels to phase transitions in theoretical
physics. However, evidence for this hypothesis is limited, as phase transitions
have not been directly observed in any social media. Here, through analysis of
100 million Weibo and 40 million Twitter users, we identify percolation-like
spread, and find that it happens more readily than current theoretical models
would predict. The lower percolation threshold can be explained by the
existence of positive feedback in the coevolution between network structure and
user activity level, such that more active users gain more followers. Moreover,
this coevolution induces an extreme imbalance in users' influence. Our findings
indicate that the ability of information to spread across social networks is
higher than expected, with implications for many information spread problems.
Chinese: 普遍认为社交媒体上的信息传播是一个渗透过程，与理论物理学中的相变有相似之处。然而，这一假设的证据有限，因为任何社交媒体中都没有直接观察到相变。在这里，通过对1亿条微博和4000万Twitter用户的分析，我们识别出了类似渗透的传播现象，并发现它比当前理论模型预测的要更容易发生。较低的渗透阈值可以通过网络结构和用户活动水平之间的共同进化中存在的正反馈来解释，即更活跃的用户获得更多的关注者。此外，这种共同进化导致用户影响力的极端不平衡。我们的发现表明，信息在社交网络中传播的能力高于预期，这对许多信息传播问题都有影响。
|
English: Grand Unified Theories (GUTs) are a very well motivated extensions of the
Standard Model (SM), but the landscape of models and possibilities is
overwhelming, and different patterns can lead to rather distinct
phenomenologies. In this work we present a way to automatise the model building
process, by considering a top to bottom approach that constructs viable and
sensible theories from a small and controllable set of inputs at the high
scale. By providing a GUT scale symmetry group and the field content, possible
symmetry breaking paths are generated and checked for consistency, ensuring
anomaly cancellation, SM embedding and gauge coupling unification. We emphasise
the usefulness of this approach for the particular case of a non-supersymmetric
SO(10) model with an intermediate left-right symmetry and we analyse how
low-energy observables such as proton decay and lepton flavour violation might
affect the generated model landscape.
Chinese: 大统一理论（GUTs）是对标准模型（SM）一个非常有力的扩展，但模型和可能性的空间非常庞大，不同的模式可能导致截然不同的现象学。在这项工作中，我们提出了一种自动化的模型构建方法，通过自上而下的方法，从高能尺度上的一个小而可控的输入集合构建可行的和有意义的理论。通过提供GUT尺度的对称群和场内容，生成并检查可能的对称破缺路径的一致性，确保了异常消除、SM嵌入和规范耦合统一。我们强调了这种方法对于具有中间左右对称的非超对称SO(10)模型的特别有用性，并分析了低能可观测量，如质子衰变和轻子味违反，如何影响生成的模型景观。
|
English: It has been observed many times, both in the Monthly and elsewhere, that the
set of all quotients of prime numbers is dense in the positive real numbers. In
this short note we answer the related question: "Is the set of all quotients of
Gaussian primes dense in the complex plane?"
Chinese: 曾多次观察到，无论是在《每月》杂志还是在其他地方，所有素数的商的集合在正实数中是稠密的。在这篇简短的笔记中，我们回答了相关的问题：“所有高斯素数的商的集合在复平面上是否也是稠密的？”
|
English: A family $\cF \subseteq 2^{[n]}$ saturates the monotone decreasing property
$\cP$ if $\cF$ satisfies $\cP$ and one cannot add any set to $\cF$ such that
property $\cP$ is still satisfied by the resulting family. We address the
problem of finding the minimum size of a family saturating the $k$-Sperner
property and the minimum size of a family that saturates the Sperner property
and that consists only of $l$-sets and $(l+1)$-sets.
Chinese: 一个集合族 $\cF \subseteq 2^{[n]}$ 满足单调递减性质 $\cP$，如果 $\cF$ 满足 $\cP$，并且无法添加任何集合到 $\cF$ 中，使得所得的集合族仍然满足性质 $\cP$。我们研究寻找满足 $k$-斯佩尔纳性质的最小集合族的大小，以及只由 $l$-集和 $(l+1)$-集组成的满足斯佩尔纳性质的最小集合族的大小。
|
English: The weighted nearest neighbors (WNN) estimator has been popularly used as a
flexible and easy-to-implement nonparametric tool for mean regression
estimation. The bagging technique is an elegant way to form WNN estimators with
weights automatically generated to the nearest neighbors; we name the resulting
estimator as the distributional nearest neighbors (DNN) for easy reference.
Yet, there is a lack of distributional results for such estimator, limiting its
application to statistical inference. Moreover, when the mean regression
function has higher-order smoothness, DNN does not achieve the optimal
nonparametric convergence rate, mainly because of the bias issue. In this work,
we provide an in-depth technical analysis of the DNN, based on which we suggest
a bias reduction approach for the DNN estimator by linearly combining two DNN
estimators with different subsampling scales, resulting in the novel two-scale
DNN (TDNN) estimator. The two-scale DNN estimator has an equivalent
representation of WNN with weights admitting explicit forms and some being
negative. We prove that, thanks to the use of negative weights, the two-scale
DNN estimator enjoys the optimal nonparametric rate of convergence in
estimating the regression function under the fourth-order smoothness condition.
We further go beyond estimation and establish that the DNN and two-scale DNN
are both asymptotically normal as the subsampling scales and sample size
diverge to infinity. For the practical implementation, we also provide variance
estimators and a distribution estimator using the jackknife and bootstrap
techniques for the two-scale DNN. These estimators can be exploited for
constructing valid confidence intervals for nonparametric inference of the
regression function. The theoretical results and appealing finite-sample
performance of the suggested two-scale DNN method are illustrated with several
numerical examples.
Chinese: 加权最近邻（WNN）估计器因其灵活且易于实现而被广泛用作均值回归估计的非参数工具。自助法是一种优雅的方式，通过自动生成最近邻权重来形成WNN估计器；我们将其称为分布式最近邻（DNN）以方便参考。然而，对于此类估计器缺乏分布式结果，限制了其在统计推断中的应用。此外，当均值回归函数具有更高阶的平滑性时，DNN未能达到最优的非参数收敛率，主要归因于偏差问题。在本工作中，我们基于此对DNN进行了深入的技术分析，并建议通过线性组合两个不同子采样尺度的DNN估计器来减少DNN估计器的偏差，从而得到新的双尺度DNN（TDNN）估计器。双尺度DNN估计器具有WNN的等效表示形式，其中权重具有显式形式且某些为负。我们证明，由于使用了负权重，双尺度DNN估计器在第四阶光滑条件下估计回归函数时享有最优的非参数收敛率。我们进一步超越了估计，并建立了DNN和双尺度DNN都是随着子采样尺度和样本大小趋向无穷大而渐近正态的。对于实际应用，我们也提供了双尺度DNN的方差估计器和使用插板和自助技术构建的分布估计器。这些估计器可用于构建有效的置信区间，以进行非参数回归函数的推断。建议的双尺度DNN方法的理论与吸引人的有限样本性能通过多个数值例子得到了说明。
|
English: We analytically calculate the spin-dependent electronic conductance through a
one-dimensional ballistic ring in the presence of an inhomogeneous magnetic
field and identify signatures of geometric and Berry phases in the general
non-adiabatic situation. For an in-plane magnetic field, we rigorously prove
the spin-flip effect presented in Frustaglia et al., Phys. Rev. Lett. 87,
256602 (2001), which allows to control and switch the polarization of outgoing
electrons by means of an Aharonov-Bohm flux, and derive analytical expressions
for the energy-averaged magneto-conductance. Our results support numerical
calculations for two-dimensional ballistic rings presented in the second paper
(Frustaglia et al., submitted to Phys. Rev. B) of this series.
Chinese: 我们通过解析计算，研究了在非均质磁场作用下，一维弹道环中自旋相关的电子电导，并识别出几何相和贝里相的一般非绝热情况下的特征。对于平面内的磁场，我们严格证明了Frustaglia等人在Phys. Rev. Lett. 87, 256602 (2001)中提出的自旋翻转效应，该效应允许通过Aharonov-Bohm flux来控制和切换出射电子的极化，并推导出能量平均磁电导的解析表达式。我们的结果支持了该系列第二篇论文（Frustaglia等，提交至Phys. Rev. B）中提出的二维弹道环的数值计算。
|
English: Data on historical populations often extends no further than numbers of
people by broad age-sex group, with nothing on numbers of births or deaths.
Demographers studying these populations have experimented with methods that use
the data on numbers of people to infer birth and death rates. These methods
have, however, received little attention since they were first developed in the
1960s. We revisit the problem of inferring demographic rates from population
structure, spelling out the assumptions needed, and specialising the methods to
the case where only child-woman ratios are available. We apply the methods to
the case of Maori populations in nineteenth-century Aotearoa New Zealand. We
find that, in this particular case, the methods reveal as much about the nature
of the data as they do about historical demographic conditions.
Chinese: 历史人口数据往往仅限于按宽泛年龄性别组的人数，缺乏出生或死亡人数数据。研究这些人口群体的人口学家曾尝试利用人数数据推算出生率和死亡率。然而，这些方法自20世纪60年代首次提出以来，未获重视。我们重新审视从人口结构推算人口率的问题，阐明所需假设，并专门化方法用于仅能获取妇儿比的情况。我们将方法应用于19世纪新西兰毛利人口案例。我们发现，在此特定案例中，这些方法揭示的数据性质与反映的历史人口状况同等重要。
|
English: We study the dependence of protoplanetary disk evolution on stellar mass
using a large sample of young stellar objects in nearby young star-forming
regions. We update the protoplanetary disk fractions presented in our recent
work (paper I of this series) derived for 22 nearby (< 500 pc) associations
between 1 and 100 Myr. We use a subsample of 1 428 spectroscopically confirmed
members to study the impact of stellar mass on protoplanetary disk evolution.
We divide this sample into two stellar mass bins (2 M$_{\odot}$ boundary) and
two age bins (3 Myr boundary), and use infrared excesses over the photospheric
emission to classify objects in three groups: protoplanetary disks, evolved
disks, and diskless. The homogeneous analysis and bias corrections allow for a
statistically significant inter-comparison of the obtained results. We find
robust statistical evidence of disk evolution dependence with stellar mass. Our
results, combined with previous studies on disk evolution, confirm that
protoplanetary disks evolve faster and/or earlier around high-mass (> 2
M$_{\odot}$) stars. We also find a roughly constant level of evolved disks
throughout the whole age and stellar mass spectra. We conclude that
protoplanetary disk evolution depends on stellar mass. Such a dependence could
have important implications for gas giant planet formation and migration, and
could contribute to explaining the apparent paucity of hot Jupiters around
high-mass stars.
Chinese: 我们研究了原行星盘演化与恒星质量之间的关系，使用了大量邻近年轻星形成区域的年轻恒星样本。我们更新了我们在最近工作中（本系列的第一篇论文）提出的原行星盘比例，这些比例是基于1至100 Myr之间22个邻近（< 500 pc）星协得出的。我们使用一个由1428个光谱确认的成员组成的子样本来研究恒星质量对原行星盘演化的影响。我们将这个样本分为两个恒星质量区间（2 M$_{\odot}$边界）和两个年龄区间（3 Myr边界），并使用红外超量相对于光球辐射来将对象分为三个组：原行星盘、演化盘和无盘。一致的分析和偏差校正允许对获得的结果进行具有统计学意义的比较。我们发现原行星盘演化与恒星质量之间依赖性的稳健统计证据。我们的结果与之前关于盘演化的研究相结合，证实了原行星盘在高质量（> 2 M$_{\odot}$）恒星周围演化得更快和/或更早。我们还发现，在整个年龄和恒星质量谱中，演化盘的水平大致保持恒定。我们得出结论，原行星盘演化依赖于恒星质量。这种依赖性可能对气态巨行星的形成和迁移有重要影响，并有助于解释为什么在高质量恒星周围热木星的数量似乎很少。
|
English: We have performed ^{59}Co-nuclear quadrupole resonance (NQR) and nuclear
magnetic resonance (NMR) studies on YCoGe, which is a reference compound of
ferromagnetic superconductor UCoGe, in order to investigate the magnetic
properties at the Co site. Magnetic and superconducting transitions were not
observed down to 0.3 K, but a conventional metallic behavior was found in
YCoGe, although its crystal structure is similar to that of UCoGe. From the
comparison between experimental results of two compounds, the ferromagnetism
and superconductivity observed in UCoGe originate from the U-5f electrons.
Chinese: 我们对钇钴镓（YCoGe）进行了 ^{59}钴核四极共振（NQR）和核磁共振（NMR）研究，这是一种铁磁性超导体UCoGe的参考化合物，目的是研究钴位点的磁性质。在0.3 K以下没有观察到磁性和超导转变，但在YCoGe中发现了常规的金属行为，尽管其晶体结构与UCoGe相似。通过比较两种化合物的实验结果，UCoGe中观察到的铁磁性和超导性源于U-5f电子。
|
English: A contemporary perspective on the tradeoff between transmit antenna diversity
and spatial multiplexing is provided. It is argued that, in the context of most
modern wireless systems and for the operating points of interest, transmission
techniques that utilize all available spatial degrees of freedom for
multiplexing outperform techniques that explicitly sacrifice spatial
multiplexing for diversity. In the context of such systems, therefore, there
essentially is no decision to be made between transmit antenna diversity and
spatial multiplexing in MIMO communication. Reaching this conclusion, however,
requires that the channel and some key system features be adequately modeled
and that suitable performance metrics be adopted; failure to do so may bring
about starkly different conclusions. As a specific example, this contrast is
illustrated using the 3GPP Long-Term Evolution system design.
Chinese: 提供了一个关于发射天线分集和空间复用之间权衡的当代观点。论证认为，在大多数现代无线系统和感兴趣的运行点中，利用所有可用的空间自由度进行复用的传输技术优于那些为了分集而明确牺牲空间复用的技术。因此，在这样的系统中，在MIMO通信中实际上没有必要在发射天线分集和空间复用之间做出选择。然而，得出这个结论需要充分地模拟信道和一些关键系统特性，并采用合适的性能指标；未能做到这一点可能会导致截然不同的结论。作为一个具体例子，这种对比通过3GPP长期演进系统设计进行了说明。
|
English: The widespread adoption of machine learning on edge devices, such as mobile
phones, laptops, IoT devices, etc., has enabled real-time AI applications in
resource-constrained environments. Existing solutions for managing
computational resources often focus narrowly on accuracy or energy efficiency,
failing to adapt dynamically to varying workloads. Furthermore, the existing
system lack robust mechanisms to adaptively balance CPU utilization, leading to
inefficiencies in resource-constrained scenarios like real-time traffic
monitoring. To address these limitations, we propose a self-adaptive approach
that optimizes CPU utilization and resource management on edge devices. Our
approach, EdgeMLBalancer balances between models through dynamic switching,
guided by real-time CPU usage monitoring across processor cores. Tested on
real-time traffic data, the approach adapts object detection models based on
CPU usage, ensuring efficient resource utilization. The approach leverages
epsilon-greedy strategy which promotes fairness and prevents resource
starvation, maintaining system robustness. The results of our evaluation
demonstrate significant improvements by balancing computational efficiency and
accuracy, highlighting the approach's ability to adapt seamlessly to varying
workloads. This work lays the groundwork for further advancements in
self-adaptation for resource-constrained environments.
Chinese: 边缘设备（如手机、笔记本电脑、物联网设备等）上机器学习的广泛应用，使得在资源受限的环境中实现了实时人工智能应用。现有的计算资源管理解决方案通常只关注精度或能效，未能动态适应不断变化的工作负载。此外，现有系统缺乏自适应平衡CPU利用率的强大机制，导致在实时交通监控等资源受限场景中效率低下。为了解决这些限制，我们提出了一种自适应方法，该方法优化了边缘设备上的CPU利用率和资源管理。我们的方法，EdgeMLBalancer，通过动态切换在处理器核心间实时监控CPU使用情况，平衡模型之间的负载。在实时交通数据上进行了测试，该方法根据CPU使用情况自适应调整目标检测模型，确保资源的高效利用。该方法利用epsilon-greedy策略，促进公平性并防止资源饥饿，保持系统鲁棒性。我们的评估结果表明，通过平衡计算效率和精度，取得了显著改进，突显了该方法适应不断变化工作负载的无缝能力。这项工作为资源受限环境中自适应技术的进一步发展奠定了基础。
|
English: Video Capsule Endoscopy (VCE) is currently one of the most effective methods
for detecting intestinal diseases. However, it is challenging to detect
early-stage small nodules with this method because they lack obvious color or
shape features. In this letter, we present a new origami capsule endoscope to
detect early small intestinal nodules using tactile sensing. Four soft tactile
sensors made out of piezoresistive material feed four channels of phase-shifted
data that are processed using a particle filter. The particle filter uses an
importance assignment template designed using experimental data from five known
sizes of modules. Moreover, the proposed capsule can use shape changes to
passively move forward or backward under peristalsis, enabling it to reach any
position in the intestine for detection. Experimental results show that the
proposed capsule can detect nodules of more than 3mm diameter with 100%
accuracy.
Chinese: 视频胶囊内窥镜(VCE)是目前检测肠道疾病的最有效方法之一。然而，由于早期小结节缺乏明显的颜色或形状特征，使用这种方法检测早期小结节具有挑战性。在本信函中，我们提出了一种新型的折纸胶囊内窥镜，用于通过触觉感知检测早期小肠结节。四个由压电电阻材料制成的柔软触觉传感器提供四个通道的相移数据，这些数据通过粒子滤波器进行处理。粒子滤波器使用一个重要性分配模板，该模板是根据五个已知模块尺寸的实验数据设计的。此外，所提出的胶囊可以利用蠕动引起的形状变化被动地向前或向后移动，使其能够到达肠道中的任何位置进行检测。实验结果表明，所提出的胶囊能够以100%的准确率检测直径超过3mm的结节。
|
English: The notion of compressed quantum computation is employed to simulate the
Ising interaction of a 1D--chain consisting out of $n$ qubits using the
universal IBM cloud quantum computer running on $\log(n)$ qubits. The external
field parameter that controls the quantum phase transition of this model
translates into particular settings of the quantum gates that generate the
circuit. We measure the magnetization, which displays the quantum phase
transition, on a two--qubit system, which simulates a four--qubit Ising chain,
and show its agreement with the theoretical prediction within a certain error.
We also discuss the relevant point of how to assess errors when using a cloud
quantum computer. As a solution, we propose to use validating circuits, that is
to run independent controlled quantum circuits of similar complexity to the
circuit of interest.
Chinese: 压缩量子计算的观念被用来模拟由 $n$ 个量子比特组成的1D链的伊辛相互作用，使用运行在 $\log(n)$ 个量子比特上的通用IBM云量子计算机。控制该模型量子相变的外部场参数转化为生成电路的量子门的特定设置。我们在一个双量子比特系统上测量磁化，该系统模拟了一个四量子比特的伊辛链，并展示了其与理论预测在某个误差范围内的吻合。我们还讨论了在使用云量子计算机时如何评估误差的相关要点。作为解决方案，我们提出使用验证电路，即运行与所关注电路具有相似复杂性的独立控制量子电路。
|
English: Realization of a short bunch beam by manipulating the longitudinal phase
space distribution with a finite longitudinal dispersion following an off-crest
accelera- tion is a widely used technique. The technique was applied in a
compact test accelerator of an energy-recovery linac scheme for compressing the
bunch length at the return loop. A diagnostic system utilizing coherent
transition radiation was developed for the beam tuning and for estimating the
bunch length. By scanning the beam parameters, we experimentally found the best
condition for the bunch compression. The RMS bunch length of 250+-50 fs was
obtained at a bunch charge of 2 pC. This result confirmed the design and the
tuning pro- cedure of the bunch compression operation for the future
energy-recovery linac (ERL).
Chinese: 通过操纵具有有限纵向色散的长脉冲纵向相空间分布，实现短脉冲束的生成是一种广泛使用的技术。该技术被应用于能量恢复直线加速器方案中的一个紧凑测试加速器中，用于在回环中压缩光束长度。为了光束调谐以及估算光束长度，开发了一套利用相干过渡辐射的诊断系统。通过扫描光束参数，我们实验上找到了光束压缩的最佳条件。在2 pC的脉冲电荷下，得到了均方根脉冲长度为250±50 fs的光束。这一结果验证了未来能量恢复直线加速器（ERL）的脉冲压缩操作的设计和调谐过程。
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.