cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Availability, storage capacity, and diffusion: Stationary states of an asymmetric exclusion process connected to two reservoirs
Creators: name: Pal, Sourav
name: Roy, Parna
name: Basu, Abhik
Publisher: name: arXiv
Year: 2023
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We explore how the interplay of finite availability, carrying capacity of particles at different parts of a spatially extended system and particle diffusion between them control the steady state currents and density profiles in a one-dimensional current-carrying channel connecting the different parts of the system. To study this, we construct a minimal model consisting of two particle reservoirs of finite carrying capacities connected by a totally asymmetric simple exclusion process (TASEP). In addition to particle transport via TASEP between the reservoirs, the latter can also directly exchange particles, modeling particle diffusion between them that can maintain a steady current in the system. We investigate the steady state density profiles and the associated particle currents in the TASEP lane. The resulting phases and the phase diagrams are quite different from an open TASEP, and are characterised by the model parameters defining particle exchanges between the TASEP and the reservoirs, direct particle exchanges between the reservoirs, and the filling fraction of the particles that determines the total resources available. These parameters can be tuned to make the density on the TASEP lane globally uniform or piecewise continuous, and can make the two reservoirs preferentially populated or depopulated.
description: 29 pages, 22 figures
Bound entangled Bell diagonal states of unequal local dimensions, and their witnesses
Creators: name: Moerland, Johannes
name: Wyderka, Nikolai
name: Kampermann, Hermann
name: Bruß, Dagmar
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Bell diagonal states constitute a well-studied family of bipartite quantum states that arise naturally in various contexts in quantum information. In this paper we generalize the notion of Bell diagonal states to the case of unequal local dimensions and investigate their entanglement properties. We extend the family of entanglement criteria of Sarbicki et al. to non-Hermitian operator bases to construct entanglement witnesses for the class of generalized Bell diagonal states. We then show how to optimize the witnesses with respect to noise robustness. Finally, we use these witnesses to construct bound entangled states that are not detected by the usual computable cross norm or realignment and de Vicente criteria.
description: 11 pages, 5 figures, 1 table; added examples in sections 2 and 5
Devouring The Centaurus A Satellites: Modeling Dwarf Galaxies with Galacticus
Creators: name: Weerasooriya, Sachi
name: Bovill, Mia Sauda
name: Taylor, Matthew A.
name: Benson, Andrew J.
name: Leahy, Cameron
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: For the first time, systematic studies of dwarf galaxies are being conducted throughout the Local Volume, including the dwarf satellites of the nearby giant elliptical galaxy Centaurus A (NGC 5128). Given Centaurus As mass (roughly ten times larger than that of the Milky Way), AGN activity, and recent major mergers, investigating the dwarf galaxies of Centaurus A and their star formation physics is imperative. However, simulating the faintest dwarfs around a galaxy of Centaurus As mass with sufficient resolution in a hydrodynamic simulation is computationally expensive and currently infeasible. In this study, we seek to reproduce the properties of Centaurus A dwarfs using the semi-analytic model Galacticus to model dwarfs within a 700 kpc region around Centaurus A, corresponding approximately to its splashback radius. We investigate the effects of host halo mass and environment and predict observable properties of Centaurus A dwarfs using astrophysical prescriptions and parameters previously tuned to match properties of the Milky Way's satellite galaxies. This approach allows us to approximately replicate cumulative luminosity functions, and luminosity metallicity and luminosity half-light-radii relations observed in the Centaurus A satellites. We provide predictions for the velocity dispersions, and star formation histories of Centaurus A dwarfs. The agreement between our predicted star formation histories for Centaurus A dwarfs and those of the Milky Way dwarfs implies the presence of universal processes governing star formation in the dwarf galaxies. Overall, our findings shed light on the star formation physics of dwarf galaxies in the Centaurus A system, revealing insights into their properties and dependence on the host environment.
description: 12 pages, 8 figures
Analytical model coupling Ekman and surface layer structure in atmospheric boundary layer flows
Creators: name: Narasimhan, Ghanesh
name: Gayme, Dennice F.
name: Meneveau, Charles
Publisher: name: arXiv
Year: 2023
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We introduce an analytical model that describes the vertical structure of Ekman boundary layer flows coupled to the Monin-Obukhov Similarity Theory (MOST) surface layer representation, which is valid for conventionally neutral (CNBL) and stable (SBL) atmospheric conditions. The model is based on a self-similar total stress distribution for both CNBL and SBL flows that merges the classic 3/2 power law profile with a MOST-consistent stress profile in the surface layer. The velocity profiles are then obtained from the Ekman momentum balance equation. The same stress model is used to derive a new self-consistent Geostrophic Drag Law (GDL). We determine the ABL depth (h) using an equilibrium boundary layer height model and parameterize the surface heat flux for quasi-steady SBL flows as a function of a prescribed surface temperature cooling rate. The ABL height and GDL equations can then be solved together to obtain the friction velocity and the cross-isobaric angle as a function of known input parameters such as the Geostrophic wind velocity magnitude and surface roughness. We show that the model predictions agree well with predictions from the literature and newly generated Large Eddy Simulation (LES). These results indicate that the proposed model provides an efficient and reasonably accurate self-consistent approach for predicting the mean wind velocity distribution in CNBL and SBL flows.
Quantum tensor network algorithms for evaluation of spectral functions on quantum computers
Creators: name: Wall, Michael L.
name: Reilly, Aidan
name: Van Dyke, John S.
name: Broholm, Collin
name: Titum, Paraj
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate quantum algorithms derived from tensor networks to simulate the static and dynamic properties of quantum many-body systems. Using a sequentially prepared quantum circuit representation of a matrix product state (MPS) that we call a quantum tensor network (QTN), we demonstrate algorithms to prepare ground and excited states on a quantum computer and apply them to molecular nanomagnets (MNMs) as a paradigmatic example. In this setting, we develop two approaches for extracting the spectral correlation functions measured in neutron scattering experiments: (a) a generalization of the SWAP test for computing wavefunction overlaps and, (b) a generalization of the notion of matrix product operators (MPOs) to the QTN setting which generates a linear combination of unitaries. The latter method is discussed in detail for translationally invariant spin-half systems, where it is shown to reduce the qubit resource requirements compared with the SWAP method, and may be generalized to other systems. We demonstrate the versatility of our approaches by simulating spin-1/2 and spin-3/2 MNMs, with the latter being an experimentally relevant model of a Cr$^{3+}_8$ ring. Our approach has qubit requirements that are independent of the number of constituents of the many-body system and scale only logarithmically with the bond dimension of the MPS representation, making them appealing for implementation on near-term quantum hardware with mid-circuit measurement and reset.
description: v3, published version, updated title
Group twirling and noise tailoring for multi-qubit controlled phase gates
Creators: name: Liu, Guoding
name: Xie, Ziyi
name: Xu, Zitai
name: Ma, Xiongfeng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Group twirling is crucial in quantum information processing, particularly in randomized benchmarking and random compiling. While protocols based on Pauli twirling have been effectively crafted to transform arbitrary noise channels into Pauli channels for Clifford gates -- thereby facilitating efficient benchmarking and mitigating worst-case errors -- practical twirling groups for multi-qubit non-Clifford gates are lacking. In this work, we study the issue of finding twirling groups for generic quantum gates within a widely used circuit structure in randomized benchmarking or random compiling. For multi-qubit controlled phase gates, which are essential in both the quantum Fourier transform and quantum search algorithms, we identify optimal twirling groups within the realm of classically replaceable unitary operations. In contrast to the simplicity of the Pauli twirling group for Clifford gates, the optimal groups for such gates are much larger, highlighting the overhead of tailoring noise channels in the presence of global non-Clifford gates.
description: 43 pages,13 figures
Multi-mode Heterodyne Laser Interferometry Realized via Software Defined Radio
Creators: name: Lin, X.
name: Hartman, M. T.
name: Zhang, S.
name: Seidelin, S.
name: Fang, B.
name: Coq, Y. Le
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optics (physics.optics)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The agile generation and control of multiple optical frequency modes combined with the realtime processing of multi-mode data provides access to experimentation in domains such as optomechanical systems, optical information processing, and multi-mode spectroscopy. The latter, specifically spectroscopy of spectral-hole burning (SHB), has motivated our development of a multi-mode heterodyne laser interferometric scheme centered around a software-defined radio platform for signal generation and processing, with development in an entirely open-source environment. A challenge to SHB is the high level of shot noise due to the laser power constraint imposed by the spectroscopic sample. Here, we have demonstrated the production, detection, and separation of multiple optical frequency modes to the benefit of optical environment sensing for realtime phase noise subtraction as well as shot noise reduction through multi-mode averaging. This has allowed us to achieve improved noise performance in low-optical-power interferometry. Although our target application is laser stabilization via SHB in cryogenic temperature rare-earth doped crystals, these techniques may be employed in a variety of different contexts.
Some new perspectives on the Kruskal--Szekeres extension with applications to photon surfaces
Creators: name: Cederbaum, Carla
name: Wolff, Markus
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 83C05, 83C75, 53B20

description: It is a well-known fact that the Schwarzschild spacetime admits a maximal spacetime extension in null coordinates which extends the exterior Schwarzschild region past the Killing horizon, called the Kruskal-Szekeres extension. This method of extending the Schwarzschild spacetime was later generalized by Brill-Hayward to a class of spacetimes of "profile $h$" across non-degenerate Killing horizons. Circumventing analytical subtleties in their approach, we reconfirm this fact by reformulating the problem as an ODE, and showing that the ODE admits a solution if and only if the naturally arising Killing horizon is non-degenerate. Notably, this approach lends itself to discussing regularity across the horizon for non-smooth metrics.
 We will discuss applications to the study of photon surfaces, extending results by Cederbaum-Galloway and Cederbaum-Jahns-Vičánek-Martínez beyond the Killing horizon. In particular, our analysis asserts that photon surfaces approaching the Killing horizon must necessarily cross it.
description: Comments are very welcome
Quantum computing through the lens of control: A tutorial introduction
Creators: name: Berberich, Julian
name: Fink, Daniel
Publisher: name: arXiv
Year: 2023
Subjects: subject: Systems and Control (eess.SY)
subject: Optimization and Control (math.OC)
subject: Quantum Physics (quant-ph)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Quantum computing is a fascinating interdisciplinary research field that promises to revolutionize computing by efficiently solving previously intractable problems. Recent years have seen tremendous progress on both the experimental realization of quantum computing devices as well as the development and implementation of quantum algorithms. Yet, realizing computational advantages of quantum computers in practice remains a widely open problem due to numerous fundamental challenges. Interestingly, many of these challenges are connected to performance, robustness, scalability, optimization, or feedback, all of which are central concepts in control theory. This paper provides a tutorial introduction to quantum computing from the perspective of control theory. We introduce the mathematical framework of quantum algorithms ranging from basic elements including quantum bits and quantum gates to more advanced concepts such as variational quantum algorithms and quantum errors. The tutorial only requires basic knowledge of linear algebra and, in particular, no prior exposure to quantum physics. Our main goal is to equip readers with the mathematical basics required to understand and possibly solve (control-related) problems in quantum computing. In particular, beyond the tutorial introduction, we provide a list of research challenges in the field of quantum computing and discuss their connections to control.
Order-2 Delaunay Triangulations Optimize Angles
Creators: name: Edelsbrunner, Herbert
name: Garber, Alexey
name: Saghafian, Morteza
Publisher: name: arXiv
Year: 2023
Subjects: subject: Combinatorics (math.CO)
subject: Computational Geometry (cs.CG)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 05B45, 52C20, 68R05

description: The local angle property of the (order-$1$) Delaunay triangulations of a generic set in $\mathbb{R}^2$ asserts that the sum of two angles opposite a common edge is less than $π$. This paper extends this property to higher order and uses it to generalize two classic properties from order-$1$ to order-$2$: (1) among the complete level-$2$ hypertriangulations of a generic point set in $\mathbb{R}^2$, the order-$2$ Delaunay triangulation lexicographically maximizes the sorted angle vector; (2) among the maximal level-$2$ hypertriangulations of a generic point set in $\mathbb{R}^2$, the order-$2$ Delaunay triangulation is the only one that has the local angle property. We also use our method of establishing (2) to give a new short proof of the angle vector optimality for the (order-1) Delaunay triangulation. For order-$1$, both properties have been instrumental in numerous applications of Delaunay triangulations, and we expect that their generalization will make order-$2$ Delaunay triangulations more attractive to applications as well.
description: 32 pages, 9 figures
Effect of scalar condensation on fermionic pole-skipping
Creators: name: Baishya, Banashree
name: Chakrabarti, Sayan
name: Maity, Debaprasad
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper, we investigated the holographic fermionic pole-skipping phenomena for a class of interacting theory in a charged AdS black hole background. We have studied two types of fermion-scalar interactions in the bulk: Dipole and Yukawa type interaction. Depending upon the interaction we introduced both real and charged scalar fields. We have particularly analyzed the effect of scalar condensation on the fermionic pole-skipping points and discussed their behaviour near critical temperatures.
description: 11 pages, 5 figures
Exploring the hierarchical structure of human plans via program generation
Creators: name: Correa, Carlos G.
name: Sanborn, Sophia
name: Ho, Mark K.
name: Callaway, Frederick
name: Daw, Nathaniel D.
name: Griffiths, Thomas L.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Human behavior is often assumed to be hierarchically structured, made up of abstract actions that can be decomposed into concrete actions. However, behavior is typically measured as a sequence of actions, which makes it difficult to infer its hierarchical structure. In this paper, we explore how people form hierarchically structured plans, using an experimental paradigm with observable hierarchical representations: participants create programs that produce sequences of actions in a language with explicit hierarchical structure. This task lets us test two well-established principles of human behavior: utility maximization (i.e. using fewer actions) and minimum description length (MDL; i.e. having a shorter program). We find that humans are sensitive to both metrics, but that both accounts fail to predict a qualitative feature of human-created programs, namely that people prefer programs with reuse over and above the predictions of MDL. We formalize this preference for reuse by extending the MDL account into a generative model over programs, modeling hierarchy choice as the induction of a grammar over actions. Our account can explain the preference for reuse and provides better predictions of human behavior, going beyond simple accounts of compressibility to highlight a principle that guides hierarchical planning.
SpaCE: The Spatial Confounding Environment
Creators: name: Tec, Mauricio
name: Trisovic, Ana
name: Audirac, Michelle
name: Woodward, Sophie
name: Hu, Jie Kate
name: Khoshnevis, Naeem
name: Dominici, Francesca
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: Methodology (stat.ME)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Spatial confounding poses a significant challenge in scientific studies involving spatial data, where unobserved spatial variables can influence both treatment and outcome, possibly leading to spurious associations. To address this problem, we introduce SpaCE: The Spatial Confounding Environment, the first toolkit to provide realistic benchmark datasets and tools for systematically evaluating causal inference methods designed to alleviate spatial confounding. Each dataset includes training data, true counterfactuals, a spatial graph with coordinates, and smoothness and confounding scores characterizing the effect of a missing spatial confounder. It also includes realistic semi-synthetic outcomes and counterfactuals, generated using state-of-the-art machine learning ensembles, following best practices for causal inference benchmarks. The datasets cover real treatment and covariates from diverse domains, including climate, health and social sciences. SpaCE facilitates an automated end-to-end pipeline, simplifying data loading, experimental setup, and evaluating machine learning and causal inference models. The SpaCE project provides several dozens of datasets of diverse sizes and spatial complexity. It is publicly available as a Python package, encouraging community feedback and contributions.
Set-valued stochastic integrals for convoluted Lévy processes
Creators: name: Xia, Weixuan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Probability (math.PR)
subject: Mathematical Finance (q-fin.MF)
subject: FOS: Mathematics
subject: FOS: Economics and business
subject: 28B20, 60G22, 60G57

description: In this paper we study set-valued Volterra-type stochastic integrals driven by Lévy processes. Upon extending the classical definitions of set-valued stochastic integral functionals to convoluted integrals with square-integrable kernels, set-valued convoluted stochastic integrals are defined by taking the closed decomposable hull of the integral functionals for generic time. We show that, aside from well-established results for set-valued Itô integrals, while set-valued stochastic integrals with respect to a finite-variation Poisson random measure are guaranteed to be integrably bounded for bounded integrands, this is not true when the random measure is of infinite variation. For indefinite integrals, we prove that it is a mutual effect of kernel singularity and jumps that the set-valued convoluted integrals are possibly explosive and take extended vector values. These results have some important implications on how set-valued fractional dynamical systems are to be constructed in general. Two classes of set-monotone processes are studied for practical interests in economic and financial modeling.
description: 28 pages
Femtoscopy with Lévy sources from SPS through RHIC to LHC
Creators: name: Csanád, Máté
name: Kincses, Dániel
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Femtoscopy is a unique tool to investigate the space-time geometry of the matter created in ultra-relativistic collisions. If the probability density distribution of hadron emission is parametrized, then the dependence of its parameters on particle momentum, collision energy, and collision geometry can be given. In recent years, several measurements came to light that indicated the adequacy of assuming a Lévy-stable shape for the mentioned distribution. In parallel, several new phenomenological developments appeared, aiding the interpretation of the experimental results or providing tools for the measurements. In this paper, we discuss important aspects of femtoscopy with Lévy sources in light of some of these advances, including phenomenological and experimental ones.
description: 14 pages, 5 figures, contribution to the 52nd International Symposium on Multiparticle Dynamics (ISMD 2023). One additional plot (right plot of Fig. 2) and discussion added in December, 2024
Black Hole and Equipotential Photon Surface Uniqueness in 4-dimensional Asymptotically Flat Electrostatic Electro-Vacuum Spacetimes
Creators: name: Borghini, Stefano
name: Cederbaum, Carla
name: Cogo, Albachiara
Publisher: name: arXiv
Year: 2024
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 53Z05, 35Q75, 83C57

description: We study 4-dimensional asymptotically flat electrostatic electro-vacuum spacetimes with a connected black hole, photon sphere, or equipotential photon surface inner boundary. Our analysis, inspired by the potential theory approach by Agostiniani-Mazzieri, allows to give self-contained proofs of known uniqueness theorems of the sub-extremal, extremal and super-extremal Reissner-Nordström spacetimes. We also obtain new results for connected photon spheres and for connected photon surfaces in the extremal case. Finally, we provide, up to a restriction on the range of their radii, the uniqueness result for connected (both non-degenerate and degenerate) photon surfaces in the super-extremal case, not yet treated in the literature.
description: 63 pages
Fermi polaron in atom-ion hybrid systems
Creators: name: Pessoa, Renato
name: Vitiello, S. A
name: Ardila, L. A Peña
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Atomic Physics (physics.atom-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Atom-ion hybrid systems are promising platforms for the quantum simulation of polaron physics in certain quantum materials. Here, we investigate the ionic Fermi polaron, a charged impurity in a polarized Fermi bath, at zero temperature using quantum Monte Carlo techniques. We compute the energy spectrum, residue, effective mass, and structural properties. Significant deviations from field-theory prediction occur in the strong coupling regime due to large density inhomogeneities around the ion. We observe a smooth polaron-molecule transition in contrast with the neutral case. This study provides insights into solid-state systems like Fermi exciton polarons in thin semiconductors and quantum technologies based on atom-ion platforms.
description: 5 Pages and Supplemental Material
Percolation as a confinement order parameter in $\mathbb{Z}_2$ lattice gauge theories
Creators: name: Linsel, Simon M.
name: Bohrdt, Annabelle
name: Homeier, Lukas
name: Pollet, Lode
name: Grusdt, Fabian
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: Lattice gauge theories (LGTs) were introduced in 1974 by Wilson to study quark confinement. These models have been shown to exhibit (de-)confined phases, yet it remains challenging to define experimentally accessible order parameters. Here we propose percolation-inspired order parameters (POPs) to probe confinement of dynamical matter in $\mathbb{Z}_2$ LGTs using electric field basis snapshots accessible to quantum simulators. We apply the POPs to study a classical $\mathbb{Z}_2$ LGT and find a confining phase up to temperature $T=\infty$ in 2D (critical $T_c$, i.e. finite-$T$ phase transition, in 3D) for any non-zero density of $\mathbb{Z}_2$ charges. Further, using quantum Monte Carlo we demonstrate that the POPs reproduce the square lattice Fradkin-Shenker phase diagram at $T=0$ and explore the phase diagram at $T>0$. The correlation length exponent coincides with the one of the 3D Ising universality class and we determine the POP critical exponent characterizing percolation. Our proposed POPs provide a geometric perspective of confinement and are directly accessible to snapshots obtained in quantum simulators, making them suitable as a probe for quantum spin liquids.
description: 5+9 pages, 4+6 figures
Stabilization of spherically symmetric static Boson stars by Coleman-Weinberg self-interaction potential
Creators: name: Eidizade, Firoozeh
name: Ghaffarnejad, Hossein
Publisher: name: arXiv
Year: 2024
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Our motivation in this work is due to the great importance of relativistic boson stars as fierce competitors of black holes. From theoretical perspective, they described by complex Klein Gordon (KG) scalar fields interacting with curved background in general form. In this work we use the Einstein-Klein Gordon (EKG) scalar tensor gravity in presence of the Coleman-Weinberg (CW) self-interaction potential to study formation of a spherically symmetric boson star and situation of its stability. We choose the CW potential because of its important role in description of cosmic inflation.
description: 24 page, 4 figures, This version is accepted to appear in the Journal of Nuclear physics B 2024
Quantum metric dependent anomalous velocity in systems subject to complex electric fields
Creators: name: Alon, Bar
name: Ilan, Roni
name: Goldstein, Moshe
Publisher: name: arXiv
Year: 2024
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Berry phases have long been known to significantly alter the properties of periodic systems, resulting in anomalous terms in the semiclassical equations of motion describing wave-packet dynamics. In non-Hermitian systems, generalizations of the Berry connection have been proposed and shown to have novel effects on dynamics and transport. In this work, we consider perturbing fields which are themselves non-Hermitian, in the form of complex external electric fields, which are realizable as gain/loss gradients. We derive the full set of semiclassical equations of motion and show that the anomalous velocity depends not only on the Berry curvature, but on the entirety of the quantum geometric tensor, including the quantum metric. This quantum metric dependent velocity appears regardless of whether the unperturbed Hamiltonian is Hermitian or not. These analytical results are compared with numerical lattice simulations which reveal these anomalous terms even in one-dimension. Our work expands the range of phenomena expected to be detectable in experimental setups, which should be realizable in currently available metamaterials and classical wave systems, including mechanical, acoustic, and optical.
description: 19 pages, 6 figures
Pard: Permutation-Invariant Autoregressive Diffusion for Graph Generation
Creators: name: Zhao, Lingxiao
name: Ding, Xueying
name: Akoglu, Leman
Publisher: name: arXiv
Year: 2024
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Graph generation has been dominated by autoregressive models due to their simplicity and effectiveness, despite their sensitivity to ordering. Yet diffusion models have garnered increasing attention, as they offer comparable performance while being permutation-invariant. Current graph diffusion models generate graphs in a one-shot fashion, but they require extra features and thousands of denoising steps to achieve optimal performance. We introduce PARD, a Permutation-invariant Auto Regressive Diffusion model that integrates diffusion models with autoregressive methods. PARD harnesses the effectiveness and efficiency of the autoregressive model while maintaining permutation invariance without ordering sensitivity. Specifically, we show that contrary to sets, elements in a graph are not entirely unordered and there is a unique partial order for nodes and edges. With this partial order, PARD generates a graph in a block-by-block, autoregressive fashion, where each block's probability is conditionally modeled by a shared diffusion model with an equivariant network. To ensure efficiency while being expressive, we further propose a higher-order graph transformer, which integrates transformer with PPGN. Like GPT, we extend the higher-order graph transformer to support parallel training of all blocks. Without any extra features, PARD achieves state-of-the-art performance on molecular and non-molecular datasets, and scales to large datasets like MOSES containing 1.9M molecules. Pard is open-sourced at https://github.com/LingxiaoShawn/Pard.
description: Diffusion Model on Graphs
MMAUD: A Comprehensive Multi-Modal Anti-UAV Dataset for Modern Miniature Drone Threats
Creators: name: Yuan, Shenghai
name: Yang, Yizhuo
name: Nguyen, Thien Hoang
name: Nguyen, Thien-Minh
name: Yang, Jianfei
name: Liu, Fen
name: Li, Jianping
name: Wang, Han
name: Xie, Lihua
Publisher: name: arXiv
Year: 2024
Subjects: subject: Robotics (cs.RO)
subject: Artificial Intelligence (cs.AI)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: In response to the evolving challenges posed by small unmanned aerial vehicles (UAVs), which possess the potential to transport harmful payloads or independently cause damage, we introduce MMAUD: a comprehensive Multi-Modal Anti-UAV Dataset. MMAUD addresses a critical gap in contemporary threat detection methodologies by focusing on drone detection, UAV-type classification, and trajectory estimation. MMAUD stands out by combining diverse sensory inputs, including stereo vision, various Lidars, Radars, and audio arrays. It offers a unique overhead aerial detection vital for addressing real-world scenarios with higher fidelity than datasets captured on specific vantage points using thermal and RGB. Additionally, MMAUD provides accurate Leica-generated ground truth data, enhancing credibility and enabling confident refinement of algorithms and models, which has never been seen in other datasets. Most existing works do not disclose their datasets, making MMAUD an invaluable resource for developing accurate and efficient solutions. Our proposed modalities are cost-effective and highly adaptable, allowing users to experiment and implement new UAV threat detection tools. Our dataset closely simulates real-world scenarios by incorporating ambient heavy machinery sounds. This approach enhances the dataset's applicability, capturing the exact challenges faced during proximate vehicular operations. It is expected that MMAUD can play a pivotal role in advancing UAV threat detection, classification, trajectory estimation capabilities, and beyond. Our dataset, codes, and designs will be available in https://github.com/ntu-aris/MMAUD.
description: Accepted by ICRA 2024
Scalable Kernel Logistic Regression with Nyström Approximation: Theoretical Analysis and Application to Discrete Choice Modelling
Creators: name: Martín-Baos, José Ángel
name: García-Ródenas, Ricardo
name: Rodriguez-Benitez, Luis
name: Bierlaire, Michel
Publisher: name: arXiv
Year: 2024
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: The application of kernel-based Machine Learning (ML) techniques to discrete choice modelling using large datasets often faces challenges due to memory requirements and the considerable number of parameters involved in these models. This complexity hampers the efficient training of large-scale models. This paper addresses these problems of scalability by introducing the Nyström approximation for Kernel Logistic Regression (KLR) on large datasets. The study begins by presenting a theoretical analysis in which: i) the set of KLR solutions is characterised, ii) an upper bound to the solution of KLR with Nyström approximation is provided, and finally iii) a specialisation of the optimisation algorithms to Nyström KLR is described. After this, the Nyström KLR is computationally validated. Four landmark selection methods are tested, including basic uniform sampling, a k-means sampling strategy, and two non-uniform methods grounded in leverage scores. The performance of these strategies is evaluated using large-scale transport mode choice datasets and is compared with traditional methods such as Multinomial Logit (MNL) and contemporary ML techniques. The study also assesses the efficiency of various optimisation techniques for the proposed Nyström KLR model. The performance of gradient descent, Momentum, Adam, and L-BFGS-B optimisation methods is examined on these datasets. Among these strategies, the k-means Nyström KLR approach emerges as a successful solution for applying KLR to large datasets, particularly when combined with the L-BFGS-B and Adam optimisation methods. The results highlight the ability of this strategy to handle datasets exceeding 200,000 observations while maintaining robust performance.
description: 34 pages, 5 figures
Expressive Higher-Order Link Prediction through Hypergraph Symmetry Breaking
Creators: name: Zhang, Simon
name: Xin, Cheng
name: Dey, Tamal K.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: A hypergraph consists of a set of nodes along with a collection of subsets of the nodes called hyperedges. Higher-order link prediction is the task of predicting the existence of a missing hyperedge in a hypergraph. A hyperedge representation learned for higher order link prediction is fully expressive when it does not lose distinguishing power up to an isomorphism. Many existing hypergraph representation learners, are bounded in expressive power by the Generalized Weisfeiler Lehman-1 (GWL-1) algorithm, a generalization of the Weisfeiler Lehman-1 algorithm. However, GWL-1 has limited expressive power. In fact, induced subhypergraphs with identical GWL-1 valued nodes are indistinguishable. Furthermore, message passing on hypergraphs can already be computationally expensive, especially on GPU memory. To address these limitations, we devise a preprocessing algorithm that can identify certain regular subhypergraphs exhibiting symmetry. Our preprocessing algorithm runs once with complexity the size of the input hypergraph. During training, we randomly replace subhypergraphs identified by the algorithm with covering hyperedges to break symmetry. We show that our method improves the expressivity of GWL-1. Our extensive experiments also demonstrate the effectiveness of our approach for higher-order link prediction on both graph and hypergraph datasets with negligible change in computation.
description: 64 pages, 8 figures
Standardization of chemically selective atomic force microscopy for metal-oxide surfaces
Creators: name: Wiesener, Philipp
name: Förster, Stefan
name: Merkel, Milena
name: Lammers, Bertram Schulze
name: Fuchs, Harald
name: Amirjalayer, Saeed
name: Mönig, Harry
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The complex atomic structures and defects of metal-oxide surfaces are vital for a variety of applications in material science and chemistry. While scanning probe microscopy allows accessing atomic-scale structures in real space, elemental discrimination and defect characterization usually rely on indirect assumptions and extensive theoretical modelling. By investigating a variety of different sample systems with increasing structural complexity and inherent defects, we demonstrate that noncontact atomic force microscopy with an O-terminated copper tip allows imaging metal-oxide surfaces with a clear elemental contrast. This universal approach provides not only immediate access to the metal- and oxygen sub-lattices, but also to the chemical and structural configuration of atomic-scale defect structures. The observed contrast can be explained by purely electrostatic interactions between the negatively charged tip apex and the strongly varying electrostatic potential between metal- and oxygen surface sites. These results offer a standardized methodology for the direct structural characterization of even most-complex metal-oxide surfaces, which is highly relevant for a fundamental understanding of atomic-scale processes on these material systems.
description: To be published
The dynamics of self-gravity wakes in the Mimas 5:3 bending wave: modifying the linear theory
Creators: name: Sega, Daniel D.
name: Stewart, Glen.
name: Colwell, Josh E.
name: Duvvuri, Girish M.
name: Jerousek, Richard
name: Esposito, Larry
Publisher: name: arXiv
Year: 2024
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The satellite Mimas launches a bending wave -- a warping of the rings that propagates radially through self-gravity -- at the 5:3 inner vertical resonance with Saturn's rings. We present a modification of the linear bending wave theory which includes the effects of satellite self-gravity wakes on the particles in the wave. We show that, when treated as rigid, these wakes generate an extra layer of particles whose number density is proportional to the magnitude of the slope of the warped ring. Using a ray-tracing code we compare our predictions with those of linear bending wave theory and with 60 stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph (UVIS) and find that the extra layer of particles of our perturbed bending wave model has a considerable explanatory power for the UVIS dataset. Our best model explains the most discrepant and surprising features of the Mimas 5:3 bending wave; the enhancement of the signal for the cases of occultations with high ring opening angle and the bigger-than-expected viscosity, $ν= 576 \, \mathrm{cm^2/s}$, which is more than double the viscosity computed from density waves. This shows that self-gravity wakes can be effective at transporting angular momentum in a vertically perturbed disk. Relative to neighboring density waves, we find a lower-than-expected value for the surface mass density, $σ= 36.7 \, \mathrm{g/cm^2}$, which suggests that the enhanced viscous interactions may be transporting material into the surrounding regions.
description: 33 pages, 14 figures. For associated code see zenodo.org/doi/10.5281/zenodo.14263069. (Changes in replacement: edit these comments to include the zenodo doi)
Search for invisible particles produced in association with single top quarks in proton-proton collisions at $\sqrt{s}$=13 TeV with the ATLAS detector
Creators: name: ATLAS Collaboration
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A search for events with one top quark and missing transverse momentum in the final state is presented. The fully hadronic decay of the top quark is explored by selecting events with a reconstructed boosted top-quark topology produced in association with large missing transverse momentum. The analysis uses 139 fb$^{-1}$ of proton-proton collision data at a centre-of-mass energy of $\sqrt{s}$=13 TeV recorded during 2015-2018 by the ATLAS detector at the Large Hadron Collider. The results are interpreted in the context of simplified models for Dark Matter particle production and the single production of a vector-like $T$ quark. In the absence of a significant excess with respect to the Standard Model expectations, 95% confidence-level upper limits on the corresponding cross-sections are obtained. The production of Dark Matter particles in association with a single top quark is excluded for masses of a scalar (vector) mediator up to 4.3 (2.3) TeV, assuming $m_χ$=1 GeV and the model couplings $λ_q$=0.6 and $λ_χ$=0.4 ($a$=0.5 and $g_χ$=1). The production of a single vector-like $T$ quark is excluded for masses below 1.8 TeV assuming a coupling to the top quark $κ_T$=0.5 and a branching ratio for $T\to Zt$ of 25%.
description: 55 pages in total, author list starting page 38, 13 figures, 3 tables, published in JHEP 05 (2024) 263. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2022-40
Solitary cluster waves in periodic potentials: Formation, propagation, and soliton-mediated particle transport
Creators: name: Antonov, Alexander P.
name: Ryabov, Artem
name: Maass, Philipp
Publisher: name: arXiv
Year: 2024
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: Transport processes in crowded periodic structures are often mediated by cooperative movements of particles forming clusters. Recent theoretical and experimental studies of driven Brownian motion of hard spheres showed that cluster-mediated transport in one-dimensional periodic potentials can proceed in form of solitary waves. We here give a comprehensive description of these solitons. Fundamental for our analysis is a static presoliton state, which is formed by a periodic arrangement of basic stable clusters. Their size follows from a geometric principle of minimum free space. Adding one particle to the presoliton state gives rise to solitons. We derive the minimal number of particles needed for soliton formation, number of solitons at larger particle numbers, soliton velocities and soliton-mediated particle currents. Incomplete relaxations of the basic clusters are responsible for an effective repulsive soliton-soliton interaction seen in measurements. A dynamical phase transition is predicted to occur in current-density relations at low temperatures. Our results provide a theoretical basis for describing experiments on cluster-mediated particle transport in periodic potentials.
description: 21 pages, 12 figures
Scrambling Transition in Free Fermion Systems Induced by a Single Impurity
Creators: name: Gao, Qucheng
name: Zhou, Tianci
name: Zhang, Pengfei
name: Chen, Xiao
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: In quantum many-body systems, interactions play a crucial role in the emergence of information scrambling. When particles interact throughout the system, the entanglement between them can lead to a rapid and chaotic spreading of quantum information, typically probed by the growth in operator size in the Heisenberg picture. In this study, we explore whether the operator undergoes scrambling when particles interact solely through a single impurity in generic spatial dimensions, focusing on fermion systems with spatial and temporal random hoppings. By connecting the dynamics of the operator to the symmetric exclusion process with a source term, we demonstrate the presence of an escape-to-scrambling transition when tuning the interaction strength for fermions in three dimensions. As a comparison, systems in lower dimensions are proven to scramble at arbitrarily weak interactions unless the hopping becomes sufficiently long-ranged. Our predictions are validated using both a Brownian circuit with a single Majorana fermion per site and a solvable Brownian SYK model with a large local Hilbert space dimension. This suggests the universality of the theoretical picture for free fermion systems with spatial and temporal randomness.
description: 11 pages, 4 figures
Two-Person Adversarial Games are Zero-Sum: An Elaboration of a Folk Theorem
Creators: name: Khan, M. Ali
name: Pedersen, Arthur Paul
name: Schrittesser, David
Publisher: name: arXiv
Year: 2024
Subjects: subject: Theoretical Economics (econ.TH)
subject: FOS: Economics and business
subject: 91A05, 91A10, 91A30

description: The observation that every two-person adversarial game is an affine transformation of a zero-sum game is traceable to Luce & Raiffa (1957) and made explicit in Aumann (1987). Recent work of (ADP) Adler et al. (2009), and of Raimondo (2023) in increasing generality, proves what has so far remained a conjecture. We present two proofs of an even more general formulation: the first draws on multilinear utility theory developed by Fishburn & Roberts (1978); the second is a consequence of the ADP proof itself for a special case of a two-player game with a set of three actions.
Approximating many-body quantum states with quantum circuits and measurements
Creators: name: Piroli, Lorenzo
name: Styliaris, Georgios
name: Cirac, J. Ignacio
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We introduce protocols to prepare many-body quantum states with quantum circuits assisted by local operations and classical communication. We show that by lifting the requirement of exact preparation, one can substantially save resources. In particular, the so-called $W$ and, more generally, Dicke states require a circuit depth and number of ancillas per site that are independent of the system size. As a byproduct of our work, we introduce an efficient scheme to implement certain non-local, non-Clifford unitary operators. We also discuss how similar ideas may be applied in the preparation of eigenstates of well-known spin models, both free and interacting.
description: Published version