cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A VLA Search for Radio Signals from M31 and M33
Creators: name: Gray, Robert H.
name: Mooley, Kunal P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: Observing nearby galaxies would facilitate the search for artificial radio signals by sampling many billions of stars simultaneously, but few efforts have been made to exploit this opportunity. An added attraction is that the Milky Way is the second-largest member of the Local Group, so our galaxy might be a probable target for hypothetical broadcasters in nearby galaxies. We present the first relatively high spectral resolution (<1 kHz) 21 cm band search for intelligent radio signals of complete galaxies in the Local Group with the Jansky VLA, observing the galaxies M31 (Andromeda) and M33 (Triangulum) - the first and third largest members of the group respectively - sampling more stars than any prior search of this kind. We used 122 Hz channels over a 1 MHz spectral window in the target galaxy velocity frame of reference, and 15 Hz channels over a 125 kHz window in our local standard of rest. No narrowband signals were detected above a signal-to-noise ratio of 7, suggesting the absence of continuous narrowband flux greater than approximately 0.24 Jy and 1.33 Jy in the respective spectral windows illuminating our part of the Milky Way during our observations in December 2014 and January 2015. This is also the first study in which the upgraded VLA has been used for SETI.
description: 14 pages, 9 figures, 5 tables. This version matches the one published in the Astronomical Journal, with some minor formatting changes
Prediction of a roton-type feature in warm dense hydrogen
Creators: name: Hamann, Paul
name: Kordts, Linda
name: Filinov, Alexey
name: Bonitz, Michael
name: Dornheim, Tobias
name: Vorberger, Jan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: In a recent Letter [T. Dornheim \textit{et al.}, Phys. Rev. Lett. \textbf{121}, 255001 (2018)], it was predicted on the basis of \textit{ab initio} quantum Monte Carlo simulations that, in a uniform electron gas, the peak $ω_0$ of the dynamic structure factor $S(q,ω)$ exhibits an unusual non-monotonic wave number dependence, where $dω_0/dq < 0$, at intermediate $q$, under strong coupling conditions. This effect was subsequently explained by the pair alignment of electrons %at an intermediate range of wave numbers [T. Dornheim \textit{et al.}, Comm. Phys. \textbf{5}, 304 (2022)]. Here we predict that this non-monotonic dispersion resembling the roton-type behavior known from superfluids should be observable in a dense, partially ionized hydrogen plasma. Based on a combination of path integral Monte Carlo simulations and linear response results for the density response function, we present the approximate range of densities, temperatures and wave numbers and make predictions for possible experimental observations.
Magnetodielectric coupling in a non-perovskite metal-organic framework
Creators: name: Basu, Tathamay
name: Jesche, A.
name: Bredenkotter, B.
name: Grzywa, M.
name: Denysenko, D.
name: Volkmer, D.
name: Loidl, A.
name: Krohns, S.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Multiferroicity and magnetodielectric coupling in metal-organic-frameworks (MOFs) is rare and so far restricted mainly to formate-based systems with perovskite structure. In the course of this work we designed a tetragonal framework [Co(C16H15N5O2)], exhibiting spin-chains of Co2+ ions, which are bridged by an organic linker containing a dipolar nitrobenzene moiety. This compound shows relaxor-like ferroelectricity at 100 K, which is followed by the onset of complex magnetic order at 15 K, indicative of weak ferromagnetism. The clear anomaly of the dielectric constant at the magnetic ordering transition indicates magnetodielectric coupling, which is also confirmed by magnetic-field dependent dielectric measurements. Weak ferromagnetism and magnetodielectric coupling, both probably result from a significant Dzyaloshinskii-Moriya interaction, which cants the spin structure and locally breaks inversion symmetry. We document that the introduction of dipolar nitrobenzene as building block in the crystal structure paths the way to design new multiferroic and magnetodielectric MOFs.
Performance Comparison of Numerical Optimization Algorithms for RSS-TOA-Based Target Localization
Creators: name: Lee, Halim
name: Seo, Jiwon
Publisher: name: arXiv
Year: 2023
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The maximum likelihood (ML) estimator can be applied to localize a target mobile device using the RSS and TOA. However, the ML estimator for the RSS-TOA-based target localization problem is nonconvex and nonlinear, having no analytical solution. Therefore, the ML estimator should be solved numerically, unless it is relaxed into a convex or linear form. This study investigates the target localization performance and computational complexity of numerical methods for solving an ML estimator. The three widely used numerical methods are: grid search, gradient descent, and particle swarm optimization. In the experimental evaluation, the grid search yielded the lowest target localization root-mean-squared error; however, the 95th percentile error of the grid search was larger than those of the other two algorithms. The average code computation time of the grid search was extremely large compared with those of the other two algorithms, and gradient descent exhibited the lowest computation time.
description: Submitted to the 2023 IEEE 97th Vehicular Technology Conference (VTC2023-Spring)
Three Dimensional Polarimetric Neutron Tomography of Magnetic Fields
Creators: name: Sales, Morten
name: Strobl, Markus
name: Shinohara, Takenao
name: Tremsin, Anton
name: Kuhn, Luise Theil
name: Lionheart, William R. B.
name: Desai, Naeem M.
name: Dahl, Anders Bjorholm
name: Schmidt, Søren
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Through the use of Time-of-Flight Three Dimensional Polarimetric Neutron Tomography (ToF 3DPNT) we have for the first time successfully demonstrated a technique capable of measuring and reconstructing three dimensional magnetic field strengths and directions unobtrusively and non-destructively with the potential to probe the interior of bulk samples which is not amenable otherwise. Using a pioneering polarimetric set-up for ToF neutron instrumentation in combination with a newly developed tailored reconstruction algorithm, the magnetic field generated by a current carrying solenoid has been measured and reconstructed, thereby providing the proof-of-principle of a technique able to reveal hitherto unobtainable information on the magnetic fields in the bulk of materials and devices, due to a high degree of penetration into many materials, including metals, and the sensitivity of neutron polarisation to magnetic fields. The technique puts the potential of the ToF time structure of pulsed neutron sources to full use in order to optimise the recorded information quality and reduce measurement time.
description: 12 pages, 4 figures
Observation of nonlinear disclination states
Creators: name: Ren, Boquan
name: Arkhipova, A. A.
name: Zhang, Yiqi
name: Kartashov, Y. V.
name: Wang, Hongguang
name: Zhuravitskii, S. A.
name: Skryabin, N. N.
name: Dyakonov, I. V.
name: Kalinkin, A. A.
name: Kulik, S. P.
name: Kompanets, V. O.
name: Chekalin, S. V.
name: Zadkov, V. N.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optics (physics.optics)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: Introduction of controllable deformations into periodic materials that lead to disclinations in their structure opens novel routes for construction of higher-order topological insulators hosting topological states at disclinations. Appearance of these topological states is consistent with the bulk-disclination correspondence principle, and is due to the filling anomaly that results in fractional charges to the boundary unit cells. So far, topological disclination states were observed only in the linear regime, while the interplay between nonlinearity and topology in the systems with disclinations has been never studied experimentally. We report here bon the experimental observation of the nonlinear photonic disclination states in waveguide arrays with pentagonal or heptagonal disclination cores inscribed in transparent optical medium using the fs-laser writing technique. The transition between nontopological and topological phases in such structures is controlled by the Kekulé distortion coefficient $r$ with topological phase hosting simultaneously disclination states at the inner disclination core and spatially separated from them corner, zero-energy, and extended edge states at the outer edge of the structure. We show that the robust nonlinear disclination states bifurcate from their linear counterparts and that location of their propagation constants in the gap and, hence, their spatial localization can be controlled by their power. Nonlinear disclination states can be efficiently excited by Gaussian input beams, but only if they are focused into the waveguides belonging to the disclination core, where such topological states reside.
description: 11 pages, 6 figures
MixedTrails: Bayesian hypothesis comparison on heterogeneous sequential data
Creators: name: Becker, Martin
name: Lemmerich, Florian
name: Singer, Philipp
name: Strohmaier, Markus
name: Hotho, Andreas
Publisher: name: arXiv
Year: 2016
Subjects: subject: Social and Information Networks (cs.SI)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: H.5.3

description: Sequential traces of user data are frequently observed online and offline, e.g., as sequences of visited websites or as sequences of locations captured by GPS. However, understanding factors explaining the production of sequence data is a challenging task, especially since the data generation is often not homogeneous. For example, navigation behavior might change in different phases of browsing a website, or movement behavior may vary between groups of users. In this work, we tackle this task and propose MixedTrails, a Bayesian approach for comparing the plausibility of hypotheses regarding the generative processes of heterogeneous sequence data. Each hypothesis is derived from existing literature, theory or intuition and represents a belief about transition probabilities between a set of states that can vary between groups of observed transitions. For example, when trying to understand human movement in a city and given some observed data, a hypothesis assuming tourists to be more likely to move towards points of interests than locals, can be shown to be more plausible than a hypothesis assuming the opposite. Our approach incorporates such hypotheses as Bayesian priors in a generative mixed transition Markov chain model, and compares their plausibility utilizing Bayes factors. We discuss analytical and approximate inference methods for calculating the marginal likelihoods for Bayes factors, give guidance on interpreting the results, and illustrate our approach with several experiments on synthetic and empirical data from Wikipedia and Flickr. Thus, this work enables a novel kind of analysis for studying sequential data in many application areas.
description: Published in Data Mining and Knowledge Discovery (2017) and presented at ECML PKDD 2017
LMSFC: A Novel Multidimensional Index based on Learned Monotonic Space Filling Curves
Creators: name: Gao, Jian
name: Cao, Xin
name: Yao, Xin
name: Zhang, Gong
name: Wang, Wei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Databases (cs.DB)
subject: FOS: Computer and information sciences

description: The recently proposed learned indexes have attracted much attention as they can adapt to the actual data and query distributions to attain better search efficiency. Based on this technique, several existing works build up indexes for multi-dimensional data and achieve improved query performance. A common paradigm of these works is to (i) map multi-dimensional data points to a one-dimensional space using a fixed space-filling curve (SFC) or its variant and (ii) then apply the learned indexing techniques. We notice that the first step typically uses a fixed SFC method, such as row-major order and z-order. It definitely limits the potential of learned multi-dimensional indexes to adapt variable data distributions via different query workloads. In this paper, we propose a novel idea of learning a space-filling curve that is carefully designed and actively optimized for efficient query processing. We also identify innovative offline and online optimization opportunities common to SFC-based learned indexes and offer optimal and/or heuristic solutions. Experimental results demonstrate that our proposed method, LMSFC, outperforms state-of-the-art non-learned or learned methods across three commonly used real-world datasets and diverse experimental settings.
description: Extended Version. Accepted by VLDB 2023
Instance Segmentation in the Dark
Creators: name: Chen, Linwei
name: Fu, Ying
name: Wei, Kaixuan
name: Zheng, Dezhi
name: Heide, Felix
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Existing instance segmentation techniques are primarily tailored for high-visibility inputs, but their performance significantly deteriorates in extremely low-light environments. In this work, we take a deep look at instance segmentation in the dark and introduce several techniques that substantially boost the low-light inference accuracy. The proposed method is motivated by the observation that noise in low-light images introduces high-frequency disturbances to the feature maps of neural networks, thereby significantly degrading performance. To suppress this ``feature noise", we propose a novel learning method that relies on an adaptive weighted downsampling layer, a smooth-oriented convolutional block, and disturbance suppression learning. These components effectively reduce feature noise during downsampling and convolution operations, enabling the model to learn disturbance-invariant features. Furthermore, we discover that high-bit-depth RAW images can better preserve richer scene information in low-light conditions compared to typical camera sRGB outputs, thus supporting the use of RAW-input algorithms. Our analysis indicates that high bit-depth can be critical for low-light instance segmentation. To mitigate the scarcity of annotated RAW datasets, we leverage a low-light RAW synthetic pipeline to generate realistic low-light data. In addition, to facilitate further research in this direction, we capture a real-world low-light instance segmentation dataset comprising over two thousand paired low/normal-light images with instance-level pixel-wise annotations. Remarkably, without any image preprocessing, we achieve satisfactory performance on instance segmentation in very low light (4~\% AP higher than state-of-the-art competitors), meanwhile opening new opportunities for future research.
description: Accepted by International Journal of Computer Vision (IJCV) 2023
Persistent dynamic magnetic state in artificial honeycomb spin ice
Creators: name: Guo, Jiasen
name: Ghosh, Pousali
name: Hill, Daniel
name: Chen, Yiyao
name: Stingaciu, Laura
name: Zolnierczuk, Piotr.
name: Ullrich, Carsten A.
name: Singh, Deepak K.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Topological magnetic charges, arising due to the non-vanishing magnetic flux on spin ice vertices, serve as the origin of magnetic monopoles that traverse the underlying lattice effortlessly. Unlike spin ice materials of atomic origin, the dynamic state in artificial honeycomb spin ice is conventionally described in terms of finite size domain wall kinetics that require magnetic field or current application. Contrary to this common understanding, here we show that thermally tunable artificial permalloy honeycomb lattice manifests a perpetual dynamic state due to self-propelled magnetic charge defect relaxation in the absence of any external tuning agent. Quantitative investigation of magnetic charge defect dynamics using neutron spin echo spectroscopy reveals sub-ns relaxation times that are comparable to monopole's relaxation in bulk spin ices. Most importantly, the kinetic process remains unabated at low temperature where thermal fluctuation is negligible. This suggests that dynamic phenomena in honeycomb spin ice are mediated by quasi-particle type entities, also confirmed by quantum Monte-Carlo simulations that replicate the kinetic behavior. Our research unveils a new `macroscopic' magnetic particle that shares many known traits of quantum particles, namely magnetic monopole and magnon.
description: 12 figures, 15 pages
Summary Report of the Animal Agriculture Symposium: Development Priorities Toward the Year 2000
Creators: name: Agency For International Development, Bureau For Science
name: U.S. Department Of Agriculture, Office Of International Development
Publisher: name: Unknown
Year: 1989
Subjects: Agricultural and Food Policy
International Development
Livestock Production/Industries
Research and Development/Tech Change/Emerging Technologies

description: Excerpts from the Executive Summary: The countries of the developing world contain 58% of the world's total land area, with 60% of the world's permanent pasture, and 53% of the world's arable land. These countries have 65% of the world's cattle, 53% of the world's sheep, 56% of the world's pigs, and 95% of the world's goats. The total number of livestock in the world indicates their importance as an economic resource. FAO figures show that in 1986 there were 1.4 billion cattle and buffalo, 1.6 billion sheep and goats, 9.3 billion poultry (including ducks and turkeys), 822 million pigs, 17 million camels, and 120 million horses, mules, and donkeys. The objectives of this symposium were to assist USAID to: Synthesize donor experience with animal agriculture and assess the appropriateness of donor policy and strategy for assistance to this subsector. Identify and set priorities for opportunities that would significantly ameliorate constraints and/or develop opportunities to improve the sustainability of animal agriculture systems. Three topical areas were considered: (1) production systems, (2) institutional and human resource development, and (3) donors and development resources.
description: Papers presented at the Symposium: The Political and Economic Context for Development of Animal Agriculture in Developing Countries (John W. Mellor); Crop-Livestock Interactions Affecting Soil Fertility in Sub-Saharan Africa (John McIntire); Importance of Animal Agriculture in Asian Production Systems (B. Gunawan); The Contribution of Animal Agriculture to Economic Welfare in Developing Countries (Lovell S. Jarvis); Role of Animal Agriculture in Farm Enterprises/Household Production and Linkage to Regional and National Economies (Benjamin Quijandria); Role of Animal Agriculture in Improving Environmental Quality (Arturo Florez); Animal Agriculture: Development Priorities Toward the Year 2000, Donor Experience Since 1960 (Peter J. Brumby); Technical Issues in Animal Agricultural Development (R.E. McDowell); Selected Issues in Animal Agricultural Development: Ruminant Nutrition (A.L. Pope); Issues and Opportunities in Development and Support Functions in Animal Agriculture (J. Henson, E. Adams, and N. Raun)
New Narrow $N(1685)$ and $N(1726)$? Remarks on the Interpretation of the Neutron Anomaly as an Interference Phenomenon
Creators: name: Kuznetsov, V.
name: Bellini, V.
name: Brio, V.
name: Gridnev, A.
name: Kozlenko, N.
name: Mammoliti, F.
name: Tortorici, F.
name: Polyakov, M. V.
name: Russo, G.
name: Sperduto, M. L.
name: Sumachev, V.
name: Sutera, C. M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Different interpretations of narrow structures at $W\sim 1.68$ and $W\sim 1.72$ GeV observed in several reactions are discussed. It is questionable whether interference phenomena could explain the whole complex of experimental findings. More probable hypotheses would be the existence of one or two narrow resonances $N(1685)$ and $N(1726)$ and/or the sub-threshold virtual $KΣ$ and $ωp$ production (cusps).
description: Published version
Spectroscopy of the $^{85}$Rb 4$D_{3/2}$ state for hyperfine-structure determination
Creators: name: Duspayev, Alisher
name: Raithel, Georg
Publisher: name: arXiv
Year: 2023
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report a measurement of the hyperfine-structure constants of the $^{85}$Rb 4$D_{3/2}$ state using a two-photon 5$S_{1/2}\rightarrow$4$D_{3/2}$ transition. The hyperfine transitions are probed by measuring the transmission of the low-power 795-nm lower-stage laser beam through a cold-atom sample as a function of 795-nm laser frequency, with the frequency of the upper-stage 1476-nm laser fixed. All 4 hyperfine components are well-resolved in the recorded transmission spectra. AC shifts are carefully considered. The field-free hyperfine line positions are obtained by extrapolating measured line positions to zero laser power. The magnetic-dipole and electric-quadrupole constants, $A$ and $B$, are determined from the hyperfine intervals to be 7.419(35)~MHz and 4.19(19)~MHz, respectively. The results are evaluated in context with previous works. Possible uses of the Rb 4$D_J$ states in Rydberg-atom-physics, precision-metrology and quantum-technology applications are discussed.
description: 9 pages, 5 figures, 2 tables
Magnetic field fluctuations analysis for the ion trap implementation of the quantum Rabi model in the the deep strong coupling regime
Creators: name: Puebla, Ricardo
name: Casanova, Jorge
name: Plenio, Martin B.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The dynamics of the quantum Rabi model in the deep strong coupling regime is theoretically analyzed in a trapped-ion setup. Recognizably, the main hallmark of this regime is the emergence of collapses and revivals, whose faithful observation is hindered under realistic magnetic dephasing noise. Here we discuss how to attain a faithful implementation of the quantum Rabi model in the deep strong coupling regime which is robust against magnetic field fluctuations and at the same time provides a large tunability of the simulated parameters. This is achieved by combining standing wave laser configuration with continuous dynamical decoupling. In addition, we study the role that amplitude fluctuations play to correctly attain the quantum Rabi model using the proposed method. In this manner the present work further supports the suitability of continuous dynamical decoupling techniques in trapped-ion settings to faithfully realize different interacting dynamics.
description: 9 pages, 3 figures
Blocking duality for $p$-modulus on networks and applications
Creators: name: Albin, Nathan
name: Clemens, Jason
name: Fernando, Nethali
name: Poggi-Corradini, Pietro
Publisher: name: arXiv
Year: 2016
Subjects: subject: Combinatorics (math.CO)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 90C27

description: This paper explores the implications of blocking duality---pioneered by Fulkerson et al.---in the context of $p$-modulus on networks. Fulkerson's blocking duality is an analogue on networks to the method of conjugate families of curves in the plane. The technique presented here leads to a general framework for studying families of objects on networks; each such family has a corresponding dual family whose $p$-modulus is essentially the reciprocal of the original family's. As an application, we give a modulus-based proof for the fact that effective resistance is a metric on graphs. This proof immediately generalizes to yield a family of graph metrics, depending on the parameter $p$, that continuously interpolates among the shortest-path metric, the effective resistance metric, and the mincut ultrametric. In a second application, we establish a connection between Fulkerson's blocking duality and the probabilistic interpretation of modulus. This connection, in turn, provides a straightforward proof of several monotonicity properties of modulus that generalize known monotonicity properties of effective resistance. Finally, we use this framework to expand on a result of Lovász in the context of randomly weighted graphs.
description: Added a new proof of the fact that effective resistance is a metric on graphs, as an application of the theory developed in this paper. As a result, we changed the title, rewrote the abstract and introduction, and added a co-author
Hydrodynamic effects on the filtered dark matter produced by a first-order phase transition
Creators: name: Jiang, Siyu
name: Huang, Fa Peng
name: Li, Chong Sheng
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Motivated by current status of dark matter (DM) search, a new type of DM production mechanism is proposed based on thedynamical process of a strong first-order phase transition in the early universe, namely, the filtered DM mechanism. We study the hydrodynamic effects on the DM relic density. By detailed calculations, we demonstrate that the hydrodynamic modes with the corresponding hydrodynamic heating effects play essential roles in determining the DM relic density. The corresponding phase transition gravitational wave could help to probe this new mechanism.
description: Published version in Physical Review D, 39 pages, 13 figures, 4 tables
Linear seesaw mechanism from dark sector
Creators: name: Hernández, A. E. Cárcamo
name: N., Vishnudath K.
name: Valle, José W. F.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We propose a minimal model where a dark sector seeds neutrino mass generation radiatively within the linear seesaw mechanism. Neutrino masses are calculable, since tree-level contributions are forbidden by symmetry. They arise from spontaneous lepton number violation by a small Higgs triplet vacuum expectation value. Lepton flavour violating processes e.g. $μ\to eγ$ can be sizeable, despite the tiny neutrino masses. We comment also on dark-matter and collider implications.
description: Matches published version
Many-body non-Hermitian skin effect under dynamic gauge coupling
Creators: name: Li, Haowei
name: Wu, Haojie
name: Zheng, Wei
name: Yi, Wei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We study an atom-cavity hybrid system where fermionic atoms in a one-dimensional lattice are subject to a cavity-induced dynamic gauge potential. The gauge coupling leads to highly-degenerate steady states in which the fermions accumulate to one edge of the lattice under an open boundary condition. Such a phenomenon originates from the many-body Liouvillian superoperator of the system, which, being intrinsically non-Hermitian, is unstable against boundary perturbations and manifests the non-Hermitian skin effect. Contrary to the single-body case, the steady state of a multi-atom system is approached much slower under the open boundary condition, as the long-time damping of the cavity mode exhibits distinct rates at different times. This stage-wise slowdown is attributed to the competition between light-assisted hopping and the dynamic gauge coupling, which significantly reduces the steady-state degeneracy under the open boundary condition, as distinct hosts of quasi-steady states dominate the dynamics at different time scales.
description: 13 pages, 7 figures
Nutational resonances, transitional precession, and precession-averaged evolution in binary black-hole systems
Creators: name: Zhao, Xinyu
name: Kesden, Michael
name: Gerosa, Davide
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In the post-Newtonian (PN) regime, the timescale on which the spins of binary black holes precess is much shorter than the radiation-reaction timescale on which the black holes inspiral to smaller separations. On the precession timescale, the angle between the total and orbital angular momenta oscillates with nutation period $τ$, during which the orbital angular momentum precesses about the total angular momentum by an angle $α$. This defines two distinct frequencies that vary on the radiation-reaction timescale: the nutation frequency $ω\equiv 2π/τ$ and the precession frequency $Ω\equiv α/τ$. We use analytic solutions for generic spin precession at 2PN order to derive Fourier series for the total and orbital angular momenta in which each term is a sinusoid with frequency $Ω- nω$ for integer $n$. As black holes inspiral, they can pass through nutational resonances ($Ω= nω$) at which the total angular momentum tilts. We derive an approximate expression for this tilt angle and show that it is usually less than $10^{-3}$ radians for nutational resonances at binary separations $r > 10M$. The large tilts occurring during transitional precession (near zero total angular momentum) are a consequence of such states being approximate $n=0$ nutational resonances. Our new Fourier series for the total and orbital angular momenta converge rapidly with $n$ providing an intuitive and computationally efficient approach to understanding generic precession that may facilitate future calculations of gravitational waveforms in the PN regime.
description: 18 pages, 9 figures, version published in PRD
Van der Waals-like Behaviour of Charged Black Holes and Hysteresis in the Dual QFTs
Creators: name: Cadoni, Mariano
name: Franzin, Edgardo
name: Tuveri, Matteo
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Using the rules of the AdS/CFT correspondence, we compute the spherical analogue of the shear viscosity, defined in terms of the retarded Green function for the stress-energy tensor for QFTs dual to five-dimensional charged black holes of general relativity with a negative cosmological constant. We show that the ratio between this quantity and the entropy density, $\tildeη/s$, exhibits a temperature-dependent hysteresis. We argue that this hysteretic behaviour can be explained by the Van der Waals-like character of charged black holes, considered as thermodynamical systems. Under the critical charge, hysteresis emerges owing to the presence of two stable states (small and large black holes) connected by a meta-stable region (intermediate black holes). A potential barrier prevents the equilibrium path between the two stable states; the system evolution must occur through the meta-stable region, and a path-dependence of $\tildeη/s$ is generated.
description: Corrected a misleading definition of \kappa\ and a typo in eq. (8)
A Hilbertian projection method for constrained level set-based topology optimisation
Creators: name: Wegert, Zachary J.
name: Roberts, Anthony P.
name: Challis, Vivien J.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: We present an extension of the projection method proposed by Challis et al. (Int J Solids Struct 45(14$\unicode{x2013}$15):4130$\unicode{x2013}$4146, 2008) for constrained level set-based topology optimisation that harnesses the Hilbertian velocity extension-regularisation framework. Our Hilbertian projection method chooses a normal velocity for the level set function as a linear combination of (1) an orthogonal projection operator applied to the extended optimisation objective shape sensitivity and (2) a weighted sum of orthogonal basis functions for the extended constraint shape sensitivities. This combination aims for the best possible first-order improvement of the optimisation objective in addition to first-order improvement of the constraints. Our formulation utilising basis orthogonalisation naturally handles linearly dependent constraint shape sensitivities. Furthermore, use of the Hilbertian extension-regularisation framework ensures that the resulting normal velocity is extended away from the boundary and enriched with additional regularity. Our approach is generally applicable to any topology optimisation problem to be solved in the level set framework. We consider several benchmark constrained microstructure optimisation problems and demonstrate that our method is effective with little-to-no parameter tuning. We also find that our method performs well when compared to a Hilbertian sequential linear programming method.
description: 23 pages, 8 figures
Magnetic field induced emergent inhomogeneity in a superconducting film with weak and homogeneous disorder
Creators: name: Ganguly, Rini
name: Roy, Indranil
name: Banerjee, Anurag
name: Singh, Harkirat
name: Ghosal, Amit
name: Raychaudhuri, Pratap
Publisher: name: arXiv
Year: 2017
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: When a magnetic field is applied, the mixed state of a conventional Type II superconductor gets destroyed at the upper critical field Hc2, where the normal vortex cores overlap with each other. Here, we show that in the presence weak and homogeneous disorder the destruction of superconductivity with field follows a different route. Starting with a weakly disordered NbN thin film ( Tc ~ 9K ), we show that under the application of magnetic field the superconducting state becomes increasingly granular, where lines of vortices separate the superconducting islands. Consequently, phase fluctuations between these islands give rise to a field induced pseudogap phase, which has a gap in the electronic density of states but where the global zero resistance state is destroyed.
description: New data added in this version
Beta Dips in the Gaia Era: Simulation Predictions of the Galactic Velocity Anisotropy Parameter for Stellar Halos
Creators: name: Loebman, Sarah R.
name: Valluri, Monica
name: Hattori, Kohei
name: Debattista, Victor P.
name: Bell, Eric F.
name: Stinson, Greg
name: Christensen, Charlotte R.
name: Brooks, Alyson
name: Quinn, Thomas R.
name: Governato, Fabio
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The velocity anisotropy parameter, beta, is a measure of the kinematic state of orbits in the stellar halo which holds promise for constraining the merger history of the Milky Way (MW). We determine global trends for beta as a function of radius from three suites of simulations, including accretion only and cosmological hydrodynamic simulations. We find that both types of simulations are consistent and predict strong radial anisotropy (~0.7) for Galactocentric radii greater than 10 kpc. Previous observations of beta for the MW's stellar halo claim a detection of an isotropic or tangential "dip" at r~20 kpc. Using the N-body+SPH simulations, we investigate the temporal persistence, population origin, and severity of "dips" in beta. We find dips in the in situ stellar halo are long-lived, while dips in the accreted stellar halo are short-lived and tied to the recent accretion of satellite material. We also find that a major merger as early as z~1 can result in a present day low (isotropic to tangential) value of beta over a wide range of radii and angular expanse. While all of these mechanisms are plausible drivers for the beta dip observed in the MW, in the simulations, each mechanism has a unique metallicity signature associated with it, implying that future spectroscopic surveys could distinguish between them. Since an accurate knowledge of beta(r) is required for measuring the mass of the MW halo, we note significant transient dips in beta could cause an overestimate of the halo's mass when using spherical Jeans equation modeling.
description: 14 pages, 7 figures, accepted to ApJ, companion paper to Hattori et al. (2017), appendix with Gaia specific predictions
Context-Aware Chart Element Detection
Creators: name: Yan, Pengyu
name: Ahmed, Saleem
name: Doermann, David
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: As a prerequisite of chart data extraction, the accurate detection of chart basic elements is essential and mandatory. In contrast to object detection in the general image domain, chart element detection relies heavily on context information as charts are highly structured data visualization formats. To address this, we propose a novel method CACHED, which stands for Context-Aware Chart Element Detection, by integrating a local-global context fusion module consisting of visual context enhancement and positional context encoding with the Cascade R-CNN framework. To improve the generalization of our method for broader applicability, we refine the existing chart element categorization and standardized 18 classes for chart basic elements, excluding plot elements. Our CACHED method, with the updated category of chart elements, achieves state-of-the-art performance in our experiments, underscoring the importance of context in chart element detection. Extending our method to the bar plot detection task, we obtain the best result on the PMC test dataset.
description: Published in ICDAR 2023. Code and model are available at https://github.com/pengyu965/ChartDete
A New Functional for Variational Mesh Generation and Adaptation Based on Equidistribution and Alignment Conditions
Creators: name: Kolasinski, Avary
name: Huang, Weizhang
Publisher: name: arXiv
Year: 2016
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65N30, 65N50

description: A new functional is presented for variational mesh generation and adaptation. It is formulated based on combining the equidistribution and alignment conditions into a single condition with only one dimensionless parameter. The functional is shown to be coercive but not convex. A solution procedure using a discrete moving mesh partial differential equation is employed. It is shown that the element volumes and altitudes of a mesh trajectory of the mesh equation associated with the new functional are bounded away from zero and the mesh trajectory stays nonsingular if it is so initially. Numerical examples demonstrate that the new functional performs comparably as an existing one that is also based on the equidistribution and alignment conditions and known to work well but contains an additional parameter.
Constraints on Primordial non-Gaussianity from Future HI Intensity Mapping Experiments
Creators: name: Li, Yi-Chao
name: Ma, Yin-Zhe
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The primordial non-Gaussianity induces scale-dependent bias of the \hi with respect to the underlying dark matter, which exhibits features on the very large scales of the 21-cm power spectrum potentially observable with \hi intensity mapping observations. We forecast the prospective constraints on the four fundamental shapes of primordial non-Gaussianity (local, equilateral, orthogonal, and enfolded), with the current and future \hi intensity mapping experiments, BINGO, FAST, and SKA-I. With the current configuration of the experiments and assumed one-year observation time, we find that the SKA-I will provide tighter constraints on the local shape of primoridal non-Gaussianity than Planck. The results are $(σ_{f^{\rm local}_{\rm NL}},σ_{f^{\rm equil}_{\rm NL}},σ_{f^{\rm orth}_{\rm NL}},σ_{f^{\rm enfold}_{\rm NL}})_{\rm SKA-I}=(0.54, 86, 25, 43)$, $(σ_{f^{\rm local}_{\rm NL}},σ_{f^{\rm equil}_{\rm NL}},σ_{f^{\rm orth}_{\rm NL}},σ_{f^{\rm enfold}_{\rm NL}})_{\rm BINGO}=(17, 100, 128, 164)$, $(σ_{f^{\rm local}_{\rm NL}},σ_{f^{\rm equil}_{\rm NL}},σ_{f^{\rm orth}_{\rm NL}},σ_{f^{\rm enfold}_{\rm NL}})_{\rm FAST}=(9.5, 44, 75, 94)$. If the lower frequency band of FAST can be used, the constraint on local-type primordial non-Gaussianity will be $σ_{f_\mathrm{NL}}\sim1.62$ which is better than Planck. In addition, if the observation time for FAST could be extended to two years, the constraint on the equilateral shape of primordial non-Gaussianity would be improved to $σ_{f_\mathrm{NL}}\sim32$. Similarly, if the observational time of SKA-I could be extended to two years, the constraint on local and orthogonal shapes could be improved to $0.43$ and $20$, respectively, achieving better constraints than Planck.
description: 11 pages, 6 figures
SwinDocSegmenter: An End-to-End Unified Domain Adaptive Transformer for Document Instance Segmentation
Creators: name: Banerjee, Ayan
name: Biswas, Sanket
name: Lladós, Josep
name: Pal, Umapada
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Instance-level segmentation of documents consists in assigning a class-aware and instance-aware label to each pixel of the image. It is a key step in document parsing for their understanding. In this paper, we present a unified transformer encoder-decoder architecture for en-to-end instance segmentation of complex layouts in document images. The method adapts a contrastive training with a mixed query selection for anchor initialization in the decoder. Later on, it performs a dot product between the obtained query embeddings and the pixel embedding map (coming from the encoder) for semantic reasoning. Extensive experimentation on competitive benchmarks like PubLayNet, PRIMA, Historical Japanese (HJ), and TableBank demonstrate that our model with SwinL backbone achieves better segmentation performance than the existing state-of-the-art approaches with the average precision of \textbf{93.72}, \textbf{54.39}, \textbf{84.65} and \textbf{98.04} respectively under one billion parameters. The code is made publicly available at: \href{https://github.com/ayanban011/SwinDocSegmenter}{github.com/ayanban011/SwinDocSegmenter}
description: Accepted to ICDAR 2023 (San Jose, California)
Easy over Hard: A Case Study on Deep Learning
Creators: name: Fu, Wei
name: Menzies, Tim
Publisher: name: arXiv
Year: 2017
Subjects: subject: Software Engineering (cs.SE)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: While deep learning is an exciting new technique, the benefits of this method need to be assessed with respect to its computational cost. This is particularly important for deep learning since these learners need hours (to weeks) to train the model. Such long training time limits the ability of (a)~a researcher to test the stability of their conclusion via repeated runs with different random seeds; and (b)~other researchers to repeat, improve, or even refute that original work. For example, recently, deep learning was used to find which questions in the Stack Overflow programmer discussion forum can be linked together. That deep learning system took 14 hours to execute. We show here that applying a very simple optimizer called DE to fine tune SVM, it can achieve similar (and sometimes better) results. The DE approach terminated in 10 minutes; i.e. 84 times faster hours than deep learning method. We offer these results as a cautionary tale to the software analytics community and suggest that not every new innovation should be applied without critical analysis. If researchers deploy some new and expensive process, that work should be baselined against some simpler and faster alternatives.
description: 12 pages, 6 figures, accepted at FSE2017
Two-dimensional Thomson scattering in high-repetition-rate laser-plasma experiments
Creators: name: Zhang, H.
name: Pilgram, J. J.
name: Constantin, C. G.
name: Rovige, L.
name: Heuer, P. V.
name: Ghazaryan, S.
name: Kaloyan, M.
name: Dorst, R. S.
name: Schaeffer, D. B.
name: Niemann, C.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: We present the first two-dimensional (2D) optical Thomson scattering measurements of electron density and temperature in laser-produced plasmas. The novel instrument directly measures $n_e(x,y)$ and $T_e(x,y)$ in two dimensions over large spatial regions (cm$^2$) with sub-mm spatial resolution, by automatically translating the scattering volume while the plasma is produced repeatedly by irradiating a solid target with a high-repetition-rate laser beam (10 J, $\sim$10$^{12}$ W/cm$^2$, 1 Hz). In this paper, we describe the design and auto-alignment of the instrument, and the computerized fitting algorithm of the spectral distribution function to large data-sets of measured scattering spectra, as they transition from the collective to the non-collective regime with distance from the target. As an example, we present 2D scattering measurements in laser driven shock waves in ambient nitrogen gas at a pressure of 95 mTorr.
description: 8 pages, 4 figures
A chip-scale polarization-spatial-momentum quantum SWAP gate in silicon nanophotonics
Creators: name: Cheng, Xiang
name: Chang, Kai-Chi
name: Xie, Zhenda
name: Sarihan, Murat Can
name: Lee, Yoo Seung
name: Li, Yongnan
name: Xu, XinAn
name: Vinod, Abhinav Kumar
name: Kocaman, Serdar
name: Yu, Mingbin
name: Lo, Patrick Guo-Qiang
name: Kwong, Dim-Lee
name: Shapiro, Jeffrey H.
name: Wong, Franco N. C.
name: Wong, Chee Wei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Recent progress in quantum computing and networking enables high-performance large-scale quantum processors by connecting different quantum modules. Optical quantum systems show advantages in both computing and communications, and integrated quantum photonics further increases the level of scaling and complexity. Here we demonstrate an efficient SWAP gate that deterministically swaps a photon's polarization qubit with its spatial-momentum qubit on a nanofabricated two-level silicon-photonics chip containing three cascaded gates. The on-chip SWAP gate is comprehensively characterized by tomographic measurements with high fidelity for both single-qubit and two-qubit operation. The coherence preservation of the SWAP gate process is verified by single-photon and two-photon quantum interference. The coherent reversible conversion of our SWAP gate facilitates a quantum interconnect between different photonic subsystems with different degrees of freedom, demonstrated by distributing four Bell states between two chips. We also elucidate the source of decoherence in the SWAP operation in pursuit of near-unity fidelity. Our deterministic SWAP gate in the silicon platform provides a pathway towards integrated quantum information processing for interconnected modular systems.
description: 25 pages, 4 figures