cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Classical versus Quantum: comparing Tensor Network-based Quantum Circuits on LHC data
Creators: name: Araz, Jack Y.
name: Spannowsky, Michael
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Machine Learning (cs.LG)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Tensor Networks (TN) are approximations of high-dimensional tensors designed to represent locally entangled quantum many-body systems efficiently. This study provides a comprehensive comparison between classical TNs and TN-inspired quantum circuits in the context of Machine Learning on highly complex, simulated LHC data. We show that classical TNs require exponentially large bond dimensions and higher Hilbert-space mapping to perform comparably to their quantum counterparts. While such an expansion in the dimensionality allows better performance, we observe that, with increased dimensionality, classical TNs lead to a highly flat loss landscape, rendering the usage of gradient-based optimization methods highly challenging. Furthermore, by employing quantitative metrics, such as the Fisher information and effective dimensions, we show that classical TNs require a more extensive training sample to represent the data as efficiently as TN-inspired quantum circuits. We also engage with the idea of hybrid classical-quantum TNs and show possible architectures to employ a larger phase-space from the data. We offer our results using three main TN ansatz: Tree Tensor Networks, Matrix Product States, and Multi-scale Entanglement Renormalisation Ansatz.
description: 18 pages, 15 figures, 1 table. Accepted version for publication in PRA
Inclusive Breakup Theory of Three-Body Halos
Creators: name: Hussein, M. S.
name: Souza, L. A.
name: Chimanski, E.
name: Carlson, B. V.
name: Frederico, T.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We present a recently developed theory for the inclusive breakup of three-fragment projectiles within a four-body spectator model \cite{CarPLB2017}, for the treatment of the elastic and inclusive non-elastic break up reactions involving weakly bound three-cluster nuclei in $A\,(a,b)\,X$ / $a = x_1 + x_2 + b$ collisions. The four-body theory is an extension of the three-body approaches developed in the 80's by Ichimura, Autern and Vincent (IAV) \cite{IAV1985}, Udagawa and Tamura (UT) \cite{UT1981} and Hussein and McVoy (HM) \cite{HM1985}. We expect that experimentalists shall be encouraged to search for more information about the $x_{1} + x_{2}$ system in the elastic breakup cross section and that also further developments and extensions of the surrogate method will be pursued, based on the inclusive non-elastic breakup part of the $b$ spectrum.
description: 8 pages, 3 figures, Contribution to the Proceedings of Fusion17: "International Conference on Heavy-Ion Collisions at Near-Barrier Energies", 20-24 February 2017 Hobart, Tasmania, Australia
STFT with Adaptive Window Width Based on the Chirp Rate
Creators: name: Pei, Soo-Chang
name: Huang, Shih-Gu
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: An adaptive time-frequency representation (TFR) with higher energy concentration usually requires higher complexity. Recently, a low-complexity adaptive short-time Fourier transform (ASTFT) based on the chirp rate has been proposed. To enhance the performance, this method is substantially modified in this paper: i) because the wavelet transform used for instantaneous frequency (IF) estimation is not signal-dependent, a low-complexity ASTFT based on a novel concentration measure is addressed; ii) in order to increase robustness to IF estimation error, the principal component analysis (PCA) replaces the difference operator for calculating the chirp rate; and iii) a more robust Gaussian kernel with time-frequency-varying window width is proposed. Simulation results show that our method has higher energy concentration than the other ASTFTs, especially for multicomponent signals and nonlinear FM signals. Also, for IF estimation, our method is superior to many other adaptive TFRs in low signal-to-noise ratio (SNR) environments.
description: Accepted by IEEE Transactions on Signal Processing
Nematic liquid crystal boojums with handles on colloidal handlebodies
Creators: name: Liu, Qingkun
name: Senyuk, Bohdan
name: Tasinkevych, Mykola
name: Smalyukh, Ivan I.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Topological defects that form on surfaces of ordered media, dubbed boojums, are ubiquitous in superfluids, liquid crystals (LCs), Langmuir monolayers, and Bose-Einstein condensates. They determine supercurrents in superfluids, impinge on electrooptical switching in polymer-dispersed LCs, and mediate chemical response at nematic-isotropic fluid interfaces, but the role of surface topology in the appearance, stability, and core structure of these defects remains poorly understood. Here, we demonstrate robust generation of boojums by controlling surface topology of colloidal particles that impose tangential boundary conditions for the alignment of LC molecules. To do this, we design handlebody-shaped polymer particles with different genus g. When introduced into a nematic LC, these particles distort the nematic molecular alignment field while obeying topological constraints and induce at least 2g - 2 boojums that allow for topological charge conservation. We characterize 3D textures of boojums using polarized nonlinear optical imaging of molecular alignment and explain our findings by invoking symmetry considerations and numerical modeling of experiment-matching director fields, order parameter variations, and nontrivial handle-shaped core structure of defects. Finally, we discuss how this interplay between the topologies of colloidal surfaces and boojums may lead to controlled self-assembly of colloidal particles in nematic and paranematic hosts, which, in turn, may enable reconfigurable topological composites.
The Maximum Isotropic Equivalent Energy Of Gamma Ray Bursts
Creators: name: Dado, Shlomo
name: Dar, Arnon
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The canonball model, which unifies cosmic ray bursts (CRBs) and gamma ray bursts (GRBs), is used to predict the maximum isotropic equivalent gamma ray energy release in a GRB. The predicted maximum is based on the observed knee around 1 TeV in the energy spectrum of Galactic cosmic ray electrons, and on the Amati correlation in GRBs. Both were predicted by the cannonball model of CRBs and GRBs before their empirical discoveries. The predicted maximum agrees well with that concluded from up to date GRB observations.
description: Expanded version, 4 figures
Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips
Creators: name: Tewari, Sumit
name: Bastiaans, Koen M.
name: Allan, Milan P.
name: van Ruitenbeek, Jan M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Scanning tunneling microscopes (STM) are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, the control of the atomic-scale shape of STM tips remains a poorly solved problem. Here, we present a method for preparing tips {\it in-situ} and for ensuring the crystalline structure and reproducibly preparing tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.
description: 12 pages preprint-style; 5 figures
On Zero Error Capacity of Nearest Neighbor Error Channels with Multilevel Alphabet
Creators: name: Nakano, Takafumi
name: Wadayama, Tadashi
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: This paper studies the zero error capacity of the Nearest Neighbor Error (NNE) channels with a multilevel alphabet. In the NNE channels, a transmitted symbol is a $d$-tuple of elements in $\{0,1,2,\dots, n-1 \}$. It is assumed that only one element error to a nearest neighbor element in a transmitted symbol can occur. The NNE channels can be considered as a special type of limited magnitude error channels, and it is closely related to error models for flash memories. In this paper, we derive a lower bound of the zero error capacity of the NNE channels based on a result of the perfect Lee codes. An upper bound of the zero error capacity of the NNE channels is also derived from a feasible solution of a linear programming problem defined based on the confusion graphs of the NNE channels. As a result, a concise formula of the zero error capacity is obtained using the lower and upper bounds.
Revisiting Click-based Interactive Video Object Segmentation
Creators: name: Vujasinovic, Stephane
name: Bullinger, Sebastian
name: Becker, Stefan
name: Scherer-Negenborn, Norbert
name: Arens, Michael
name: Stiefelhagen, Rainer
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: While current methods for interactive Video Object Segmentation (iVOS) rely on scribble-based interactions to generate precise object masks, we propose a Click-based interactive Video Object Segmentation (CiVOS) framework to simplify the required user workload as much as possible. CiVOS builds on de-coupled modules reflecting user interaction and mask propagation. The interaction module converts click-based interactions into an object mask, which is then inferred to the remaining frames by the propagation module. Additional user interactions allow for a refinement of the object mask. The approach is extensively evaluated on the popular interactive~DAVIS dataset, but with an inevitable adaptation of scribble-based interactions with click-based counterparts. We consider several strategies for generating clicks during our evaluation to reflect various user inputs and adjust the DAVIS performance metric to perform a hardware-independent comparison. The presented CiVOS pipeline achieves competitive results, although requiring a lower user workload.
description: ICIP 2022. 5 pages = 4 pages of content + 1 page of references
Edge pinning and transformation of defect lines induced by faceted colloidal rings in nematic liquid crystals
Creators: name: Senyuk, Bohdan
name: Liu, Qingkun
name: Yuan, Ye
name: Smalyukh, Ivan I.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Nematic colloids exhibit a large diversity of topological defects and structures induced by colloidal particles in the orientationally ordered liquid crystal host fluids. These defects and field configurations define elastic interactions and medium-mediated self-assembly, as well as serve as model systems in exploiting the richness of interactions between topologies and geometries of colloidal surfaces, nematic fields, and topological singularities induced by particles in the nematic bulk and at nematic-colloidal interfaces. Here we demonstrate formation of quarter-strength surface-pinned disclinations, as well as a large variety of director field configurations with splitting and reconnections of singular defect lines, prompted by colloidal particles with sharp edges and size large enough to define strong boundary conditions. Using examples of faceted ring-shaped particles of genus g = 1, we explore transformation of defect lines as they migrate between locations in the bulk of the nematic host to edge-pinned locations at the surfaces of particles and vice versa, showing that this behavior is compliant with topological constraints defined by mathematical theorems. We discuss how transformation of bulk and surface defect lines induced by faceted colloids can enrich the diversity of elasticity-mediated colloidal interactions and how these findings may impinge on prospects of their controlled reconfigurable self-assembly in nematic hosts.
Uncertainty Estimation for Heatmap-based Landmark Localization
Creators: name: Schobs, Lawrence
name: Swift, Andrew J.
name: Lu, Haiping
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Image and Video Processing (eess.IV)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Automatic anatomical landmark localization has made great strides by leveraging deep learning methods in recent years. The ability to quantify the uncertainty of these predictions is a vital component needed for these methods to be adopted in clinical settings, where it is imperative that erroneous predictions are caught and corrected. We propose Quantile Binning, a data-driven method to categorize predictions by uncertainty with estimated error bounds. Our framework can be applied to any continuous uncertainty measure, allowing straightforward identification of the best subset of predictions with accompanying estimated error bounds. We facilitate easy comparison between uncertainty measures by constructing two evaluation metrics derived from Quantile Binning. We compare and contrast three epistemic uncertainty measures (two baselines, and a proposed method combining aspects of the two), derived from two heatmap-based landmark localization model paradigms (U-Net and patch-based). We show results across three datasets, including a publicly available Cephalometric dataset. We illustrate how filtering out gross mispredictions caught in our Quantile Bins significantly improves the proportion of predictions under an acceptable error threshold. Finally, we demonstrate that Quantile Binning remains effective on landmarks with high aleatoric uncertainty caused by inherent landmark ambiguity, and offer recommendations on which uncertainty measure to use and how to use it. The code and data are available at https://github.com/schobs/qbin.
description: 14 pages, in IEEE Transactions on Medical Imaging, 2022
Robust FCC solute diffusion predictions from ab-initio machine learning methods
Creators: name: Wu, Henry
name: Lorenson, Aren
name: Anderson, Ben
name: Witteman, Liam
name: Wu, Haotian
name: Meredig, Bryce
name: Morgan, Dane
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We evaluate the performance of four machine learning methods for modeling and predicting FCC solute diffusion barriers. More than 200 FCC solute diffusion barriers from previous density functional theory (DFT) calculations served as our dataset to train four machine learning methods: linear regression (LR), decision tree (DT), Gaussian kernel ridge regression (GKRR), and artificial neural network (ANN). We separately optimize key physical descriptors favored by each method to model diffusion barriers. We also assess the ability of each method to extrapolate when faced with new hosts with limited known data. GKRR and ANN were found to perform the best, showing 0.15 eV cross-validation errors and predicting impurity diffusion in new hosts to within 0.2 eV when given only 5 data points from the host. We demonstrate the success of a combined DFT + data mining approach towards solving materials science challenges and predict the diffusion barrier of all available impurities across all FCC hosts.
description: 13 pages, 4 figures
New families satisfying the Dynamical Uniform Boundedness Principle over function fields
Creators: name: Doyle, John R.
name: Faber, Xander
Publisher: name: arXiv
Year: 2022
Subjects: subject: Number Theory (math.NT)
subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 37P35 (Primary) 11G30, 14H51, 37P05, 37P15 (Secondary)

description: We extend a technique, originally due to the first author and Poonen, for proving cases of the Strong Uniform Boundedness Principle (SUBP) in algebraic dynamics over function fields of positive characteristic. The original method applied to unicritical polynomials for which the characteristic does not divide the degree. We show that many new 1-parameter families of polynomials satisfy the SUBP, including the family of all quadratic polynomials in even characteristic. We also give a new family of non-polynomial, non-Lattès rational functions that satisfies the SUBP.
description: 14 pages; main results now hold over 1-dimensional function fields over arbitrary fields of positive characteristic (not just finite fields); to appear in Mathematische Annalen
The effects of data preprocessing on probability of default model fairness
Creators: name: Wu, Di
Publisher: name: arXiv
Year: 2024
Subjects: subject: Econometrics (econ.EM)
subject: FOS: Economics and business

description: In the context of financial credit risk evaluation, the fairness of machine learning models has become a critical concern, especially given the potential for biased predictions that disproportionately affect certain demographic groups. This study investigates the impact of data preprocessing, with a specific focus on Truncated Singular Value Decomposition (SVD), on the fairness and performance of probability of default models. Using a comprehensive dataset sourced from Kaggle, various preprocessing techniques, including SVD, were applied to assess their effect on model accuracy, discriminatory power, and fairness.
A Kennicutt-Schmidt relation at molecular cloud scales and beyond
Creators: name: Khoperskov, Sergey A.
name: Vasiliev, Evgenii O.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Using N-body/gasdynamic simulations of a Milky Way-like galaxy we analyse a Kennicutt-Schmidt relation, $Σ_{SFR} \propto Σ_{gas}^N$, at different spatial scales. We simulate synthetic observations in CO lines and UV band. We adopt the star formation rate defined in two ways: based on free fall collapse of a molecular cloud - $Σ_{SFR, cl}$, and calculated by using a UV flux calibration - $Σ_{SFR, UV}$. We study a KS relation for spatially smoothed maps with effective spatial resolution from molecular cloud scales to several hundred parsecs. We find that for spatially and kinematically resolved molecular clouds the $Σ_{SFR, cl} \propto Σ_{\rm gas}^N$ relation follows the power-law with index $N \approx 1.4$. Using UV flux as SFR calibrator we confirm a systematic offset between the $Σ_{\rm UV}$ and $Σ_{\rm gas}$ distributions on scales compared to molecular cloud sizes. Degrading resolution of our simulated maps for surface densities of gas and star formation rates we establish that there is no relation $Σ_{\rm SFR, UV} - Σ_{\rm gas}$ below the resolution $\sim 50$ pc. We find a transition range around scales $\sim 50-120$ pc, where the power-law index $N$ increases from 0 to 1-1.8 and saturates for scales larger $\sim 120$ pc. A value of the index saturated depends on a surface gas density threshold and it becomes steeper for higher $Σ_{gas}$ threshold. Averaging over scales with size of $>150$ pc the power-law index $N$ equals 1.3-1.4 for surface gas density threshold $\sim 5 M_\odot$pc$^{-2}$. At scales $>120$ pc surface SFR densities determined by using CO data and UV flux, $Σ_{\rm SFR, UV}/Σ_{\rm SFR, cl}$, demonstrate a discrepancy about a factor of 3. We argue that this may be originated from overestimating (constant) values of conversion factor, star formation efficiency or UV calibration used in our analysis.
description: 8 pages, 3 figures, accepted for publication in MNRAS
Open-Air Microwave Entanglement Distribution for Quantum Teleportation
Creators: name: Gonzalez-Raya, Tasio
name: Casariego, Mateo
name: Fesquet, Florian
name: Renger, Michael
name: Salari, Vahid
name: Möttönen, Mikko
name: Omar, Yasser
name: Deppe, Frank
name: Fedorov, Kirill G.
name: Sanz, Mikel
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Microwave technology plays a central role in current wireless communications, standing among them mobile communication and local area networks (LANs). The microwave range shows relevant advantages with respect to other frequencies in open-air transmission, such as low absorption losses and low energy consumption, and it is additionally the natural working frequency in superconducting quantum technologies. Entanglement distribution between separate parties is at the core of secure quantum communications. Therefore, understanding its limitations in realistic open-air settings, specially in the rather unexplored microwave regime, is crucial for transforming microwave quantum communications into a mainstream technology. Here, we investigate the feasibility of an open-air entanglement distribution scheme with microwave two-mode squeezed states. First, we study the reach of direct entanglement transmission in open-air, obtaining a maximum distance of approximately 500 meters in a realistic setting with state-of-the-art experimental parameters. Afterwards, we adapt entanglement distillation and entanglement swapping protocols to microwave technology in order to reduce environmental entanglement degradation. While entanglement distillation helps to increase quantum correlations in the short-distance low-squeezing regime by up to $46\%$, entanglement swapping increases the reach by $14\%$. Then, we compute the fidelity of a continuous-variable quantum teleportation protocol using open-air-distributed entanglement as a resource. Finally, we adapt the machinery to explore the limitations of quantum communication between satellites, where the thermal noise impact is substantially reduced and diffraction losses are dominant.
Aldous' spectral gap property for normal Cayley graphs on symmetric groups
Creators: name: Li, Yuxuan
name: Xia, Binzhou
name: Zhou, Sanming
Publisher: name: arXiv
Year: 2022
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C50, 05C25

description: Aldous' spectral gap conjecture states that the second largest eigenvalue of any connected Cayley graph on the symmetric group Sn with respect to a set of transpositions is achieved by the standard representation of Sn. This celebrated conjecture, which was proved in its general form in 2010, has inspired much interest in searching for other families of Cayley graphs on Sn with the property that the largest eigenvalue strictly smaller than the degree is attained by the standard representation of Sn. In this paper, we prove three results on normal Cayley graphs on Sn possessing this property for sufficiently large n, one of which can be viewed as a generalization of the "normal" case of Aldous' spectral gap conjecture.
description: Final version published in European Journal of Combinatorics
Spin Cross-Correlation Experiments in an Electron Entangler
Creators: name: Bordoloi, Arunav
name: Zannier, Valentina
name: Sorba, Lucia
name: Schönenberger, Christian
name: Baumgartner, Andreas
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Correlations are fundamental in describing many body systems - not only in natural sciences. However, in experiments, correlations are notoriously difficult to assess on the microscopic scale, especially for electron spins. Here, we demonstrate a direct measurement of the spin cross-correlations between the currents of a Cooper pair splitter, an electronic device that emits electrons originating from Cooper pairs in a superconductor. While it is firmly established theoretically that these electron pairs form maximally spin-entangled singlet states with opposite spin projections, no spin correlation experiments have been demonstrated so far. We use ferromagnetic sidegates, compatible with superconducting electronic structures, to individually spin polarize the transmissions of two quantum dots fabricated in the two electronic paths, which act as tunable spin filters. The signals are detected in standard transport and in highly sensitive transconductance experiments. We find that the spin-cross correlation is negative, compatible with spin singlet emission, and deviates from the ideal value mostly due to a finite overlap of the Zeeman split quantum dot states. Our results demonstrate a new route to perform spin auto- and cross correlation experiments in nanometer scaled electronic devices, especially suitable for those relying on magnetic field sensitive superconducting elements, like unconventional, triplet or topologically non-trivial superconductors, or to perform Bell tests with massive particles, like electrons.
A Noise-level-aware Framework for PET Image Denoising
Creators: name: Li, Ye
name: Cui, Jianan
name: Chen, Junyu
name: Zeng, Guodong
name: Wollenweber, Scott
name: Jansen, Floris
name: Jang, Se-In
name: Kim, Kyungsang
name: Gong, Kuang
name: Li, Quanzheng
Publisher: name: arXiv
Year: 2022
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: Medical Physics (physics.med-ph)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: In PET, the amount of relative (signal-dependent) noise present in different body regions can be significantly different and is inherently related to the number of counts present in that region. The number of counts in a region depends, in principle and among other factors, on the total administered activity, scanner sensitivity, image acquisition duration, radiopharmaceutical tracer uptake in the region, and patient local body morphometry surrounding the region. In theory, less amount of denoising operations is needed to denoise a high-count (low relative noise) image than images a low-count (high relative noise) image, and vice versa. The current deep-learning-based methods for PET image denoising are predominantly trained on image appearance only and have no special treatment for images of different noise levels. Our hypothesis is that by explicitly providing the local relative noise level of the input image to a deep convolutional neural network (DCNN), the DCNN can outperform itself trained on image appearance only. To this end, we propose a noise-level-aware framework denoising framework that allows embedding of local noise level into a DCNN. The proposed is trained and tested on 30 and 15 patient PET images acquired on a GE Discovery MI PET/CT system. Our experiments showed that the increases in both PSNR and SSIM from our backbone network with relative noise level embedding (NLE) versus the same network without NLE were statistically significant with p<0.001, and the proposed method significantly outperformed a strong baseline method by a large margin.
Defining Time Crystals via Representation Theory
Creators: name: Khemani, Vedika
name: von Keyserlingk, C. W.
name: Sondhi, S. L.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Time crystals are proposed states of matter which spontaneously break time translation symmetry. There is no settled definition of such states. We offer a new definition which follows the traditional recipe for Wigner symmetries and order parameters. Supplementing our definition with a few plausible assumptions we find that a) systems with time independent Hamiltonians should not exhibit TTSB while b) the recently studied $π$ spin glass/Floquet time crystal can be viewed as breaking a global internal symmetry and as breaking time translation symmetry as befits its two names.
Strong Coordination over Noisy Channels: Is Separation Sufficient?
Creators: name: Obead, Sarah A.
name: Vellambi, Badri N.
name: Kliewer, Jörg
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We study the problem of strong coordination of actions of two agents $X$ and $Y$ that communicate over a noisy communication channel such that the actions follow a given joint probability distribution. We propose two novel schemes for this noisy strong coordination problem, and derive inner bounds for the underlying strong coordination capacity region. The first scheme is a joint coordination-channel coding scheme that utilizes the randomness provided by the communication channel to reduce the local randomness required in generating the action sequence at agent $Y$. The second scheme exploits separate coordination and channel coding where local randomness is extracted from the channel after decoding. Finally, we present an example in which the joint scheme is able to outperform the separate scheme in terms of coordination rate.
description: 9 pages, 4 figures. An extended version of a paper accepted for the IEEE International Symposium on Information Theory (ISIT), 2017
Low-scale leptogenesis with flavour and CP symmetries
Creators: name: Drewes, Marco
name: Georis, Yannis
name: Hagedorn, Claudia
name: Klarić, Juraj
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider a type-I seesaw framework with a flavour symmetry from the series of non-abelian groups $Δ(3 n^2)$ and $Δ(6 n^2)$ and a CP symmetry. Breaking these symmetries non-trivially results in the right-handed neutrinos being degenerate in mass up to possible (further symmetry-breaking) splittings $κ$ and $λ$, while the neutrino Yukawa coupling matrix encodes the entire flavour structure in the neutrino sector. For a fixed combination of flavour and CP symmetry and residual groups, this matrix has five real free parameters. Four of them are set by light neutrino masses and data on lepton mixing, while $θ_R$ is related to right-handed neutrinos. We scrutinise for all four lepton mixing patterns, grouped into Case 1) through Case 3 b.1), the potential to generate the baryon asymmetry of the Universe (BAU) through low-scale leptogenesis numerically and analytically. The main results are: a) the possible correlation of the BAU and the Majorana phases of the PMNS mixing matrix in certain instances; b) the possibility to generate the correct amount of BAU for zero $κ$ and $λ$ as well as for large $κ$, depending on the case and choice of group theory parameters; c) the chance to produce sufficient BAU for large active-sterile mixing angles, enabling direct experimental tests at current and future facilities, for $θ_R$ close to a special value, potentially protected by an enhanced residual symmetry. We elucidate these results with representative examples of flavour and CP symmetries, which all lead to a good agreement with the measured lepton mixing angles and, possibly, the current hint of the CP phase $δ$. We identify the CP-violating combinations relevant for low-scale leptogenesis, and show that the parametric dependence of the BAU found numerically can be understood well with their help.
description: 65 pages + 19 pages of appendices, 41 figures, 10 tables. Matches the version published in JHEP
Nearly Maximally Predictive Features and Their Dimensions
Creators: name: Marzen, Sarah E.
name: Crutchfield, James P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Information Theory (cs.IT)
subject: Chaotic Dynamics (nlin.CD)
subject: Machine Learning (stat.ML)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Scientific explanation often requires inferring maximally predictive features from a given data set. Unfortunately, the collection of minimal maximally predictive features for most stochastic processes is uncountably infinite. In such cases, one compromises and instead seeks nearly maximally predictive features. Here, we derive upper-bounds on the rates at which the number and the coding cost of nearly maximally predictive features scales with desired predictive power. The rates are determined by the fractal dimensions of a process' mixed-state distribution. These results, in turn, show how widely-used finite-order Markov models can fail as predictors and that mixed-state predictive features offer a substantial improvement.
description: 6 pages, 2 figures; Supplementary materials, 5 pages, 1 figure; http://csc.ucdavis.edu/~cmg/compmech/pubs/nmpf.htm
Estimating parameter uncertainty in binding-energy models by the frequency-domain bootstrap
Creators: name: Bertsch, G. F.
name: Bingham, Derek
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We propose using the frequency-domain bootstrap (FDB) to estimate errors of modeling parameters when the modeling error is itself a major source of uncertainty. Unlike the usual bootstrap or the simple $χ^2$ analysis, the FDB can take into account correlations between errors. It is also very fast compared to the the Gaussian process Bayesian estimate as often implemented for computer model calibration. The method is illustrated drop model of nuclear binding energies. We find that the FDB gives a more conservative estimate of the uncertainty in liquid drop parameters in better accord with more empirical estimates. For the nuclear physics application, there no apparent obstacle to apply the method to the more accurate and detailed models based on density-functional theory.
description: 10 pages, 5 figures, submitted to Physical Review Letters
Warm deformed $R^{2}$ inflation
Creators: name: Payaka, Apirak
name: Amaek, Waluka
name: Channuie, Phongpichit
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work, we study warm inflationary scenario based on a deformation of $R^{2}$ gravity. We start considering $R^{p}$ and assume $p=2(1+δ)$ with $δ\ll 1$ so that we simply obtain warm $R^{2}$ inflation when setting $δ=0$. We then derive the potential in the Einstein frame and consider a dissipation parameter of the form $Γ= C_{1}T$ with $C_1$ being a coupling parameter. We focus only on the strong regime of which the interaction between inflaton and radiation fluid has been taken into account. We compute inflationary observables and constrain the parameters of our model using latest observational data reported by Planck. From our analysis, we discover that with proper choices of parameters the derived $n_s$ and $r$ are in good agreement with the Planck 2018 observational constraints. Particularly, we constrain the potential scale $U_{0}$ of the models.
description: v3: 20 pages, 5 figures,, version accepted for publication in Nuclear Physics B
Angstrofluidics: walking to the limit
Creators: name: You, Yi
name: Ismail, Abdulghani
name: Nam, Gwang-Hyeon
name: Goutham, Solleti
name: Keerthi, Ashok
name: Radha, Boya
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Angstrom-scale fluidic channels are ubiquitous in nature, and play an important role in regulating cellular traffic, signaling, and responding to stimuli. Synthetic channels are now a reality with the emergence of several cutting-edge bottom-up and top-down fabrication methods. In particular, the use of atomically thin two dimensional (2D) materials and nanotubes as components to build fluidic conduits has pushed the limits of fabrication to the Angstrom-scale. Here, we provide an overview of the recent developments in the fabrication methods for nano- and angstrofluidic channels while categorizing them on the basis of dimensionality (0D pores, 1D tubes, 2D slits), along with the latest advances in measurement techniques. We discuss the ionic transport governed by various stimuli in these channels and draw comparison of ionic mobility, streaming and osmotic power, with varying pore sizes across all the dimensionalities. Towards the end of the review, we highlight the unique future opportunities in the development of smart ionic devices.
description: Keywords: Angstrofluidics, nanofluidics, confinement, ion transport, 2D materials, molecular transport 6 figures, review article
Tambour de bravade "Bacchas", détail de l'attache du timbre
Creators: name: Musée National Des Arts Et Traditions Populaires (Paris)
name: Centre D'ethnologie Française
Publisher: name: École des Hautes Études en Sciences Sociales; Institut  interdisciplinaire d'anthropologie du contemporain (Paris); Laboratoire d'anthropologie et d'histoire de l'institution de la culture (Paris)
Year: 2024

Abstract
Low power In Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures
Creators: name: Vakili, Hamed
name: Ganguly, Samiran
name: de Coster, George J.
name: Neupane, Mahesh R.
name: Ghosh, Avik W.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The surface state of a 3D topological insulator (3DTI) is a spin-momentum locked conductive state, whose large spin hall angle can be used for the energy-efficient spin orbit torque based switching of an overlying ferromagnet (FM). Conversely, the gated switching of the magnetization of a separate FM in or out of the TI surface plane, can turn on and off the TI surface current. The gate tunability of the TI Dirac cone gap helps reduce its sub-threshold swing. By exploiting this reciprocal behaviour, we can use two FM/3DTI heterostructures to design a 1-Transistor 1-magnetic tunnel junction random access memory unit (1T1MTJ RAM) for an ultra low power Processing-in-Memory (PiM) architecture. Our calculation involves combining the Fokker-Planck equation with the Non-equilibrium Green Function (NEGF) based flow of conduction electrons and Landau-Lifshitz-Gilbert (LLG) based dynamics of magnetization. Our combined approach allows us to connect device performance metrics with underlying material parameters, which can guide proposed experimental and fabrication efforts.
description: 5 pages, 4 figures
Massette fabriquée par Marius Fabre pour un tambourin exposé à Paris en 1937 et à New York en 1939
Creators: name: Musée National Des Arts Et Traditions Populaires (Paris)
name: Centre D'ethnologie Française
Publisher: name: École des Hautes Études en Sciences Sociales; Institut  interdisciplinaire d'anthropologie du contemporain (Paris); Laboratoire d'anthropologie et d'histoire de l'institution de la culture (Paris)
Year: 2024

Abstract
Varying dilaton as a tracer of classical string interactions
Creators: name: Dodelson, Matthew
name: Silverstein, Eva
name: Torroba, Gonzalo
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We analyze tree-level string amplitudes in a linear dilaton background, motivated by its use as a gauge-invariant tracer of string interactions in scattering experiments and its genericity among simple perturbative string theory limits. A simple case is given by a lightlike dependence for the dilaton. The zero mode of the embedding coordinate in the direction of dilaton variation requires special care. Employing Gaussian wave packets and a well-defined modification of the dilaton profile far from the dominant interaction region, we obtain finite results which explicitly reproduce the interaction timescales expected from joining and splitting interactions involving oscillating strings in simple string scattering processes. There is an interesting interplay between the effects of the linear dilaton and the $iε$ prescription. In more general circumstances this provides a method for tracing the degree of non-locality in string interactions, and it gives a basis for further studies of perturbative supercritical string theory at higher loop order.
description: 18 pages. v2: small typo corrections
Superintegrable classical Zernike system
Creators: name: Pogosyan, George S.
name: Wolf, Kurt Bernardo
name: Yakhno, Alexander
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We consider the differential equation that Zernike proposed to classify aberrations of wavefronts in a circular pupil, as if it were a classical Hamiltonian with a non-standard potential. The trajectories turn out to be closed ellipses. We show that this is due to the existence of higher-order invariants that close into a cubic Higgs algebra. The Zernike classical system thus belongs to the class of superintegrable systems. Its Hamilton-Jacobi action separates in three vertical projections of polar coordinates of a sphere, polar and equidistant coordinates on half-hyperboloids, and also in elliptic coordinates on the sphere.
description: Submitted to J Math Phys
Stretching-induced conductance variations as fingerprints of contact configurations in single-molecule junctions
Creators: name: Kim, Yong-Hoon
name: Kim, Hu Sung
name: Lee, Juho
name: Tsutsui, Makusu
name: Kawai, Tomoji
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Molecule-electrode contact atomic structures are a critical factor that characterizes molecular devices, but their precise understanding and control still remain elusive. Based on combined first-principles calculations and single-molecule break junction experiments, we herein establish that the conductance of alkanedithiolate junctions can both increase and decrease with mechanical stretching and the specific trend is determined by the S-Au linkage coordination number (CN) or the molecule-electrode contact atomic structure. Specifically, we find that the mechanical pulling results in the conductance increase for the junctions based on S-Au CN two and CN three contacts, while the conductance is minimally affected by stretching for junctions with the CN one contact and decreases upon the formation of Au monoatomic chains. Detailed analysis unravels the mechanisms involving the competition between the stretching-induced upshift of the highest occupied molecular orbital-related states toward the Fermi level of electrodes and the deterioration of molecule-electrode electronic couplings in different contact CN cases. Moreover, we experimentally find a higher chance to observe the conductance enhancement mode under a faster elongation speed, which is explained by ab initio molecular dynamics simulations that reveal an important role of thermal fluctuations in aiding deformations of contacts into low-coordination configurations that include monoatomic Au chains. Pointing out the insufficiency in previous notions of associating peak values in conductance histograms with specific contact atomic structures, this work resolves the controversy on the origins of ubiquitous multiple conductance peaks in S-Au-based single-molecule junctions.
description: 11 pages, 4 figures; to be published in J. Am. Chem. Soc
Lack of lead poison awareness among Bangladeshi women
Creators: name: Research, Nature
Publisher: name: Manara - Qatar Research Repository
Year: 2023
Subjects: classificationCode: 42
subject: Health sciences
subject: FOS: Health sciences
classificationCode: 4206
subject: Public health

description: Women of childbearing age from various parts of Bangladesh living in the capital city Dhaka were surveyed about their levels of awareness and potential behaviours that could lead to lead exposure and toxicity. The study, conducted by researchers from BRAC University in Dhaka, found that the women surveyed, regardless of their educational level, lacked awareness about the potential sources of lead poisoning . Women who had an education beyond the secondary level claimed to be aware of the harmful effects of lead but this was not reflected in their everyday behaviours. Lead poisoning occurs when the metal accumulates in the body over a long period of time. Unborn and young children are especially vulnerable because they absorb up to five times as much ingested lead as adults from a given source. This can affect their physical and mental development. Lead poisoning can lead to learning difficulties, fatigue, memory loss, mood disorders, miscarriages and premature births. Although many countries around the world, including Bangladesh, have introduced policies to reduce potential sources of lead exposure, their implementation is often lacking. Common sources of lead exposure in Bangladesh include soil fertilizers, paints, solder used in food cans, some spices, and traditional cosmetics. The survey was conducted among 114 women of childbearing age. Approximately half the group received an education above the secondary level, while the rest did not. Levels of awareness about potential sources of lead toxicity were generally low across the whole group. Only 22% of the more educated group said that they were aware that paint could contain lead. The study also found that because of their more privileged lifestyles, the more educated women were more exposed to certain lead sources than the less educated group. For example, only 16% of the less educated women lived in painted houses while all the women in the more educated group did. Also, the more educated women were more likely to use ayurvedic or herbal medicines, a potential source of lead exposure in Bangladesh, than the less educated group. On the other hand, the less educated women were more exposed to lead through gardening, eating visible fat on cooked meat, and using traditional cosmetics. “Prevention of unregulated sources of lead poisoning is important,” the study’s authors write in the Journal of Local and Global Health Sciences. They recommend the development of awareness programmes, particularly among women of childbearing age.Other InformationPublished in: QScience.com Highlights, Published by Nature Research for Hamad bin Khalifa University Press (HBKU Press)
License: http://creativecommons.org/licenses/by/4.0