cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Coherent phase slips in coupled matter-wave circuits
Creators: name: Pérez-Obiol, Axel
name: Polo, Juan
name: Amico, Luigi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Quantum Phase slips are dual process of particle tunneling in coherent networks. Besides to be of central interest for condensed matter physics, quantum phase slips are resources that are sought to be manipulated in quantum circuits. Here, we devise a specific matter-wave circuit enlightening quantum phase slips. Specifically, we investigate the quantum many body dynamics of two side-by-side ring-shaped neutral bosonic systems coupled through a weak link. By imparting a suitable magnetic flux, persistent currents flow in each ring with given winding numbers. We demonstrate that coherent phase slips occur as winding number transfer among the two rings, with the populations in each ring remaining nearly constant. Such a phenomenon occurs as a result of a specific entanglement of circulating states, that, as such cannot be captured by a mean field treatment of the system. Our work can be relevant for the observation of quantum phase slips in cold atoms experiments and their manipulation in matter-wave circuits. To make contact with the field, we show that the phenomenon has clear signatures in the momentum distribution of the system providing the time of flight image of the condensate.
The relationship between health beliefs and use of child car safety restraints among mothers of young children
Creators: name: Leifried, Stacy Lynn
Publisher: name: University of Nevada, Las Vegas
Year: 1997

description: Though preventable, injuries resulting from motor vehicle accidents are the leading cause of death and disability in childhood. The literature supports the efficacy of child car safety restraints, yet despite this fact, nonuse rates remain high. Using the Health Belief Model, the purpose of this descriptive correlational study was to examine the relationship between health beliefs, cues to action, selected demographics, and mothers' use of child car safety restraints among low income mothers of children less than five years of age; Locus of control, maternal seatbelt use, and child's age were demonstrated to be significant predictors of child car safety restraint use. The greater the mother's external locus of control and the more consistent the mother herself wore a seatbelt, the more consistent the use of a child car safety restraint. Use of child car safety restraints decreased as child's age increased and infants were more likely to be consistently restrained than toddlers.
Time complexity analysis of quantum difference methods for linear high dimensional and multiscale partial differential equations
Creators: name: Jin, Shi
name: Liu, Nana
name: Yu, Yue
Publisher: name: arXiv
Year: 2022
Subjects: subject: Numerical Analysis (math.NA)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We investigate time complexities of finite difference methods for solving the high-dimensional linear heat equation, the high-dimensional linear hyperbolic equation and the multiscale hyperbolic heat system with quantum algorithms (hence referred to as the "quantum difference methods"). For the heat and linear hyperbolic equations we study the impact of explicit and implicit time discretizations on quantum advantages over the classical difference method. For the multiscale problem, we find the time complexity of both the classical treatment and quantum treatment for the explicit scheme scales as $\mathcal{O}(1/\varepsilon)$, where $\varepsilon$ is the scaling parameter, while the scaling for the multiscale Asymptotic-Preserving (AP) schemes does not depend on $\varepsilon$. This indicates that it is still of great importance to develop AP schemes for multiscale problems in quantum computing.
description: quantum difference methods
Of Shadows and Gaps in Spatial Search
Creators: name: Chan, Ada
name: Godsil, Chris
name: Tamon, Christino
name: Xie, Weichen
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Combinatorics (math.CO)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: Spatial search occurs in a connected graph if a continuous-time quantum walk on the adjacency matrix of the graph, suitably scaled, plus a rank-one perturbation induced by any vertex will unitarily map the principal eigenvector of the graph to the characteristic vector of the vertex. This phenomenon is a natural continuous-time analogue of Grover search. The spatial search is said to be optimal if it occurs with constant fidelity and in time inversely proportional to the shadow of the target vertex on the principal eigenvector. Extending a result of Chakraborty et al. (Physical Review A, 102:032214, 2020), we prove a simpler characterization of optimal spatial search. Based on this characterization, we observe that some families of distance-regular graphs, such as Hamming and Grassmann graphs, have optimal spatial search. We also show a matching lower bound on time for spatial search with constant fidelity, which extends a bound due to Farhi and Gutmann for perfect fidelity. Our elementary proofs employ standard tools, such as Weyl inequalities and Cauchy determinant formula.
description: 25 pages, 3 figures. Current version: fixed minor typo in Theorem 1 and proof for cycles; clarified assumption on model
Reference-based Video Super-Resolution Using Multi-Camera Video Triplets
Creators: name: Lee, Junyong
name: Lee, Myeonghee
name: Cho, Sunghyun
name: Lee, Seungyong
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: We propose the first reference-based video super-resolution (RefVSR) approach that utilizes reference videos for high-fidelity results. We focus on RefVSR in a triple-camera setting, where we aim at super-resolving a low-resolution ultra-wide video utilizing wide-angle and telephoto videos. We introduce the first RefVSR network that recurrently aligns and propagates temporal reference features fused with features extracted from low-resolution frames. To facilitate the fusion and propagation of temporal reference features, we propose a propagative temporal fusion module. For learning and evaluation of our network, we present the first RefVSR dataset consisting of triplets of ultra-wide, wide-angle, and telephoto videos concurrently taken from triple cameras of a smartphone. We also propose a two-stage training strategy fully utilizing video triplets in the proposed dataset for real-world 4x video super-resolution. We extensively evaluate our method, and the result shows the state-of-the-art performance in 4x super-resolution.
description: CVPR 2022
Time-dependent galactic winds I. Structure and evolution of galactic outflows accompanied by cosmic ray acceleration
Creators: name: Dorfi, E. A.
name: Breitschwerdt, D.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: 85-08

description: Cosmic rays are transported out of the galaxy by diffusion and advection due to streaming along magnetic field lines and resonant scattering off self-excited MHD waves. Thus momentum is transferred to the plasma via the frozen-in waves as a mediator assisting the thermal pressure in driving a galactic wind. The bulk of the Galactic CRs are accelerated by shock waves generated in SNRs, a significant fraction of which occur in OB associations on a timescale of several $10^7$ years. We examine the effect of changing boundary conditions at the base of the galactic wind due to sequential SN explosions on the outflow. Thus pressure waves will steepen into shock waves leading to in situ post-acceleration of GCRs. We performed simulations of galactic winds in flux tube geometry appropriate for disk galaxies, describing the CR diffusive-advective transport in a hydrodynamical fashion along with the energy exchange with self-generated MHD waves. Our time-dependent CR hydrodynamic simulations confirm the existence of time asymptotic outflow solutions (for constant boundary conditions). It is also found that high-energy particles escaping from the Galaxy and having a power-law distribution in energy ($\propto E^{-2.7}$) similar to the Milky Way with an upper energy cut-off at $\sim 10^{15}$ eV are subjected to efficient and rapid post-SNR acceleration in the lower galactic halo up to energies of $10^{17} - 10^{18}$ eV by multiple shock waves propagating through the halo. The particles can gain energy within less than $3\,$kpc from the galactic plane corresponding to flow times less than $5\cdot 10^6\,$years. The mechanism described here offers a natural solution to explain the power-law distribution of CRs between the "knee" and the "ankle". The mechanism described here offers a natural and elegant solution to explain the power-law distribution of CRs between the "knee" and the "ankle".
description: 15 pages, 7 figures
In-plane electronic confinement in superconducting LaAlO$_3$/SrTiO$_3$ nanostructures
Creators: name: Stornaiuolo, D.
name: Gariglio, S.
name: Couto, N. J. G.
name: Fete, A.
name: Caviglia, A. D.
name: Seyfarth, G.
name: Jaccard, D.
name: Morpurgo, A. F.
name: Triscone, J. -M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We describe the transport properties of mesoscopic devices based on the two dimensional electron gas (2DEG) present at the LaAlO$_3$/SrTiO$_3$ interface. Bridges with lateral dimensions down to 500~nm were realized using electron beam lithography. Their detailed characterization shows that processing and confinement do not alter the transport parameters of the 2DEG. The devices exhibit superconducting behavior tunable by electric field effect. In the normal state, we measured universal conductance fluctuations, signature of phase-coherent transport in small structures. The achievement of reliable lateral confinement of the 2DEG opens the way to the realization of quantum electronic devices at the LaAlO$_3$/SrTiO$_3$ interface.
description: 10 pages, 4 figures
Anharmonic thermodynamic properties and phase boundary across the post-perovskite transition in MgSiO$_3$
Creators: name: Zhang, Zhen
name: Wentzcovitch, Renata M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: To address the effects of lattice anharmonicity across the perovskite to post-perovskite transition in MgSiO$_3$, we conduct calculations using the phonon quasiparticle (PHQ) approach. The PHQ is based on \textit{ab initio} molecular dynamics and, in principle, captures full anharmonicity. Free energies in the thermodynamic limit ($N \rightarrow \infty$) are computed using temperature-dependent quasiparticle dispersions within the phonon gas model. Systematic results on anharmonic thermodynamic properties and phase boundary are reported. Both the local density approximation (LDA) and the generalized gradient approximation (GGA) calculations are performed to provide confident constraints on these properties. Anharmonic effects are demonstrated by comparing results with those obtained using the quasiharmonic approximation (QHA). The inadequacy of the QHA is indicated by its overestimation of thermal expansivity and thermodynamic Grüneisen parameter and its converged isochoric heat capacity in the high-temperature limit. The PHQ phase boundary has a Clapeyron slope ($dP/dT$) that increases with temperature. This result contrasts with the nearly zero curvature of the QHA phase boundary. Anharmonicity bends the phase boundary to lower temperatures at high pressures. Implications for the double-crossing of the phase boundary by the mantle geotherm are discussed.
Inverse Multislice Ptychography by Layer-wise Optimisation and Sparse Matrix Decomposition
Creators: name: Bangun, Arya
name: Melnyk, Oleh
name: März, Benjamin
name: Diederichs, Benedikt
name: Clausen, Alexander
name: Weber, Dieter
name: Filbir, Frank
name: MÜller-Caspary, Knut
Publisher: name: arXiv
Year: 2022
Subjects: subject: Information Theory (cs.IT)
subject: Optics (physics.optics)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: We propose algorithms based on an optimisation method for inverse multislice ptychography in, e.g. electron microscopy. The multislice method is widely used to model the interaction between relativistic electrons and thick specimens. Since only the intensity of diffraction patterns can be recorded, the challenge in applying inverse multislice ptychography is to uniquely reconstruct the electrostatic potential in each slice up to some ambiguities. In this conceptual study, we show that a unique separation of atomic layers for simulated data is possible when considering a low acceleration voltage. We also introduce an adaptation for estimating the illuminating probe. For the sake of practical application, we finally present slice reconstructions using experimental 4D scanning transmission electron microscopy (STEM) data.
Exact Solutions of a Deep Linear Network
Creators: name: Ziyin, Liu
name: Li, Botao
name: Meng, Xiangming
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (stat.ML)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: This work finds the analytical expression of the global minima of a deep linear network with weight decay and stochastic neurons, a fundamental model for understanding the landscape of neural networks. Our result implies that the origin is a special point in deep neural network loss landscape where highly nonlinear phenomenon emerges. We show that weight decay strongly interacts with the model architecture and can create bad minima at zero in a network with more than $1$ hidden layer, qualitatively different from a network with only $1$ hidden layer. Practically, our result implies that common deep learning initialization methods are insufficient to ease the optimization of neural networks in general.
description: NeurIPS 2022
CoCoLoT: Combining Complementary Trackers in Long-Term Visual Tracking
Creators: name: Dunnhofer, Matteo
name: Micheloni, Christian
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: How to combine the complementary capabilities of an ensemble of different algorithms has been of central interest in visual object tracking. A significant progress on such a problem has been achieved, but considering short-term tracking scenarios. Instead, long-term tracking settings have been substantially ignored by the solutions. In this paper, we explicitly consider long-term tracking scenarios and provide a framework, named CoCoLoT, that combines the characteristics of complementary visual trackers to achieve enhanced long-term tracking performance. CoCoLoT perceives whether the trackers are following the target object through an online learned deep verification model, and accordingly activates a decision policy which selects the best performing tracker as well as it corrects the performance of the failing one. The proposed methodology is evaluated extensively and the comparison with several other solutions reveals that it competes favourably with the state-of-the-art on the most popular long-term visual tracking benchmarks.
description: International Conference on Pattern Recognition (ICPR) 2022
Pion and nucleon in two flavour QCD with unimproved Wilson fermions
Creators: name: Chowdhury, Abhishek
name: De, Asit K.
name: De Sarkar, Sangita
name: Harindranath, A.
name: Maiti, Jyotirmoy
name: Mondal, Santanu
name: Sarkar, Anwesa
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We calculate pion mass, pion decay constant, PCAC quark mass and nucleon mass in two flavour lattice QCD with unimproved Wilson fermion and gauge actions. Simulations are performed using DD-HMC algorithm at two lattice spacings and two volumes for several values of the quark mass. The cutoff effects in pion mass and nucleon mass for the explored region of parameter space are found to be negligible. The chiral behaviours of pion mass, pion decay constant and quark condensate are found to be qualitatively consistent with NLO chiral perturbation theory.
description: 18 pages and 15 figures
Spectral gap and strict outerness for actions of locally compact groups on full factors
Creators: name: Marrakchi, Amine
name: Vaes, Stefaan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Operator Algebras (math.OA)
subject: FOS: Mathematics

description: We prove that an outer action of a locally compact group $G$ on a full factor $M$ is automatically strictly outer, meaning that the relative commutant of $M$ in the crossed product is trivial. If moreover the image of $G$ in the outer automorphism group $\operatorname{Out} M$ is closed, we prove that the crossed product remains full. We obtain this result by proving that the inclusion of $M$ in the crossed product automatically has a spectral gap property. Such results had only been proven for actions of discrete groups and for actions of compact groups, by using quite different methods in both cases. Even for the canonical Bogoljubov actions on free group factors or free Araki-Woods factors, these results are new.
description: v2: minor changes, final version, to appear in Enseignement Mathematique, special issue in honor of Vaughan Jones
A Gödel Calculus for Linear Temporal Logic
Creators: name: Aguilera, Juan Pablo
name: Diéguez, Martín
name: Fernández-Duque, David
name: McLean, Brett
Publisher: name: arXiv
Year: 2022
Subjects: subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences

description: We consider Gödel temporal logic ($\sf GTL$), a variant of linear temporal logic based on Gödel--Dummett propositional logic. In recent work, we have shown this logic to enjoy natural semantics both as a fuzzy logic and as a superintuitionistic logic. Using semantical methods, the logic was shown to be {\sc pspace}-complete. In this paper we provide a deductive calculus for $\sf GTL$, and show this calculus to be sound and complete for the above-mentioned semantics.
description: arXiv admin note: text overlap with arXiv:2205.00574
Techniques for Feature Extraction In Speech Recognition System : A Comparative Study
Creators: name: Shrawankar, Urmila
name: Thakare, V M
Publisher: name: arXiv
Year: 2013
Subjects: subject: Sound (cs.SD)
subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: The time domain waveform of a speech signal carries all of the auditory information. From the phonological point of view, it little can be said on the basis of the waveform itself. However, past research in mathematics, acoustics, and speech technology have provided many methods for converting data that can be considered as information if interpreted correctly. In order to find some statistically relevant information from incoming data, it is important to have mechanisms for reducing the information of each segment in the audio signal into a relatively small number of parameters, or features. These features should describe each segment in such a characteristic way that other similar segments can be grouped together by comparing their features. There are enormous interesting and exceptional ways to describe the speech signal in terms of parameters. Though, they all have their strengths and weaknesses, we have presented some of the most used methods with their importance.
description: Pages: 9 Figures : 3
Generic nonadditivity of quantum capacity in simple channels
Creators: name: Leditzky, Felix
name: Leung, Debbie
name: Siddhu, Vikesh
name: Smith, Graeme
name: Smolin, John A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Information Theory (cs.IT)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Determining capacities of quantum channels is a fundamental question in quantum information theory. Despite having rigorous coding theorems quantifying the flow of information across quantum channels, their capacities are poorly understood due to super-additivity effects. Studying these phenomena is important for deepening our understanding of quantum information, yet simple and clean examples of super-additive channels are scarce. Here we study a family of channels called platypus channels. Its simplest member, a qutrit channel, is shown to display super-additivity of coherent information when used jointly with a variety of qubit channels. Higher-dimensional family members display super-additivity of quantum capacity together with an erasure channel. Subject to the "spin-alignment conjecture" introduced in the companion paper [IEEE Trans. Inf. Theory 69(6), pp. 3825-3849, 2023; arXiv:2202.08380], our results on super-additivity of quantum capacity extend to lower-dimensional channels as well as larger parameter ranges. In particular, super-additivity occurs between two weakly additive channels each with large capacity on their own, in stark contrast to previous results. Remarkably, a single, novel transmission strategy achieves super-additivity in all examples. Our results show that super-additivity is much more prevalent than previously thought. It can occur across a wide variety of channels, even when both participating channels have large quantum capacity.
description: Comments: 25 pages, 9 figures. v2: matches published version. See also the companion paper arXiv:2202.08380
Complete frequency-bin Bell basis synthesizer
Creators: name: Seshadri, Suparna
name: Lu, Hsuan-Hao
name: Leaird, Daniel E.
name: Weiner, Andrew M.
name: Lukens, Joseph M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report the experimental generation of all four frequency-bin Bell states in a single versatile setup via successive pumping of spontaneous parametric downconversion with single and dual spectral lines. Our scheme utilizes intensity modulation to control the pump configuration and offers turn-key generation of any desired Bell state using only off-the-shelf telecommunication equipment. We employ Bayesian inference to reconstruct the density matrices of the generated Bell states, finding fidelities $\geq$ 97% for all cases. Additionally, we demonstrate the sensitivity of the frequency-bin Bell states to common-mode and differential-mode temporal delays traversed by the photons comprising the state$\unicode{x2013}$presenting the potential for either enhanced resolution or nonlocal sensing enabled by our complete Bell basis synthesizer.
Security against collective attacks for a continuous-variable quantum key distribution protocol using homodyne detection and postselection
Creators: name: Namiki, Ryo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We analyze the security against collective attacks for a homodyne-based continuous-variable quantum key distribution protocol using binary coherent states and postselection. We derive a lower bound of the secret key rate in an asymptotic scenario, and numerically optimize it for the case of a symmetric Gaussian channel.
description: 7 pages, 2 figures
Stripe correlations in the two-dimensional Hubbard-Holstein model
Creators: name: Karakuzu, Seher
name: Ly, Andy Tanjaroon
name: Mai, Peizhi
name: Neuhaus, James
name: Maier, Thomas A.
name: Johnston, Steven
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Several state-of-the-art numerical methods have observed static or fluctuating spin and charge stripes in doped two-dimensional Hubbard models, suggesting that these orders play a significant role in shaping the cuprate phase diagram. Many experiments, however, also indicate that the cuprates have strong electron-phonon ($e$-ph) coupling, and it is unclear how this interaction influences stripe correlations. We study static and fluctuating stripe orders in the doped singleband Hubbard-Holstein model using zero temperature variational Monte Carlo and finite temperature determinant quantum Monte Carlo. We find that the lattice couples more strongly with the charge component of the stripes, leading to an enhancement or suppression of stripe correlations, depending on model parameters like the next-nearest-neighbor hopping $t^\prime$ or phonon energy $Ω$. Our results help elucidate how the $e$-ph interaction can tip the delicate balance between stripe and superconducting correlations in the Hubbard-Holstein model with implications for our understanding of the high-$T_\mathrm{c}$ cuprates.
description: 9 pages, 5 figures plus supplementary material. Comments are welcome
Fluctuations and correlations in Polyakov loop extended chiral fluid dynamics
Creators: name: Herold, Christoph
name: Bleicher, Marcus
name: Nahrgang, Marlene
Publisher: name: arXiv
Year: 2013
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We study nonequilibrium effects at the QCD phase transition within the framework of Polyakov loop extended chiral fluid dynamics. The quark degrees of freedom act as a locally equilibrated heat bath for the sigma field and a dynamical Polyakov loop. Their evolution is described by a Langevin equation with dissipation and noise. At a critical point we observe the formation of long-range correlations after equilibration. During a hydrodynamical expansion nonequilibrium fluctuations are enhanced at the first order phase transition compared to the critical point.
description: 6 pages, 7 figures, presented at SQM 2011
Gravitational scattering of spinning neutrinos by a rotating black hole with a slim magnetized accretion disk
Creators: name: Dvornikov, Maxim
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study neutrinos gravitationally scattered off a rotating supermassive black hole which is surrounded by a thin accretion disk with a realistic magnetic field. Neutrinos are supposed to be Dirac particles having a nonzero magnetic moment. Neutrinos move along arbitrary trajectories, with the incoming flux being parallel to the equatorial plane. We exactly account for the influence of both gravity and the magnetic field on the neutrino motion and its spin evolution. The general statement that the helicity of an ultrarelativistic neutrino is constant in the particle scattering in an arbitrary gravitational field is proven within the quasiclassical approach. We find the measurable fluxes of outgoing neutrinos taking into account the neutrino spin precession in the external field in curved spacetime. These fluxes turn out to be significantly suppressed for some parameters of the system. Finally, we discuss the possibility to observe the predicted phenomena for core-collapsing supernova neutrinos in our Galaxy.
description: 16 pages in LaTeX2e, 11 eps figures; paper is significantly extended, Fig. 3 is added, new appendix is included; version to be published in Classical and Quantum Gravity
title: Untersuchungen über die hallstattzeitliche Technik für Bronzeeinlagen in Eisen
Creators: name: Eichhorn, Peter
name: Rollig, Hans
name: Schwarz, Ute
name: Urbon, Benno
name: Zwicker, Ulrich
Publisher: name: University Library Heidelberg
Year: 2015

description: [nicht vorhanden]
Existence, Uniqueness and Removable Singularities for Nonlinear Partial Differential Equations in Geometry
Creators: name: Harvey, F. Reese
name: Lawson, H. Blaine
Publisher: name: arXiv
Year: 2013
Subjects: subject: Analysis of PDEs (math.AP)
subject: Complex Variables (math.CV)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 35-02, 35J25, 35J70, 53C38, 53C56, 32U05, 32U30

description: This paper surveys some recent results on existence, uniqueness and removable singularities for fully nonlinear differential equations on manifolds. The discussion also treats restriction theorems and the strong Bellman principle.
Interconnect Parasitics and Partitioning in Fully-Analog In-Memory Computing Architectures
Creators: name: Amin, Md Hasibul
name: Elbtity, Mohammed
name: Zand, Ramtin
Publisher: name: arXiv
Year: 2022
Subjects: subject: Hardware Architecture (cs.AR)
subject: Emerging Technologies (cs.ET)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Fully-analog in-memory computing (IMC) architectures that implement both matrix-vector multiplication and non-linear vector operations within the same memory array have shown promising performance benefits over conventional IMC systems due to the removal of energy-hungry signal conversion units. However, maintaining the computation in the analog domain for the entire deep neural network (DNN) comes with potential sensitivity to interconnect parasitics. Thus, in this paper, we investigate the effect of wire parasitic resistance and capacitance on the accuracy of DNN models deployed on fully-analog IMC architectures. Moreover, we propose a partitioning mechanism to alleviate the impact of the parasitic while keeping the computation in the analog domain through dividing large arrays into multiple partitions. The SPICE circuit simulation results for a 400 X 120 X 84 X 10 DNN model deployed on a fully-analog IMC circuit show that a 94.84% accuracy could be achieved for MNIST classification application with 16, 8, and 8 horizontal partitions, as well as 8, 8, and 1 vertical partitions for first, second, and third layers of the DNN, respectively, which is comparable to the ~97% accuracy realized by digital implementation on CPU. It is shown that accuracy benefits are achieved at the cost of higher power consumption due to the extra circuitry required for handling partitioning.
description: 5 pages, 6 figures
Bifurcation analysis for axisymmetric capillary water waves with vorticity and swirl
Creators: name: Erhardt, André
name: Wahlén, Erik
name: Weber, Jörg
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35B07, 35B32, 76B15, 76B45, 76B47

description: We study steady axisymmetric water waves with general vorticity and swirl, subject to the influence of surface tension. This can be formulated as an elliptic free boundary problem in terms of Stokes' stream function. A change of variables allows us to overcome the generic coordinate-induced singularities and to cast the problem in the form "identity plus compact", which is amenable to Rabinowitz' global bifurcation theorem, while no restrictions regarding the absence of stagnation points in the flow have to be made. Within the scope of this new formulation, local and global solution curves, bifurcating from laminar flows with a flat surface, are constructed.
The Distressing Ads That Persist: Uncovering The Harms of Targeted Weight-Loss Ads Among Users with Histories of Disordered Eating
Creators: name: Gak, Liza
name: Olojo, Seyi
name: Salehi, Niloufar
Publisher: name: arXiv
Year: 2022
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: Targeted advertising can harm vulnerable groups when it targets individuals' personal and psychological vulnerabilities. We focus on how targeted weight-loss advertisements harm people with histories of disordered eating. We identify three features of targeted advertising that cause harm: the persistence of personal data that can expose vulnerabilities, over-simplifying algorithmic relevancy models, and design patterns encouraging engagement that can facilitate unhealthy behavior. Through a series of semi-structured interviews with individuals with histories of unhealthy body stigma, dieting, and disordered eating, we found that targeted weight-loss ads reinforced low self-esteem and deepened pre-existing anxieties around food and exercise. At the same time, we observed that targeted individuals demonstrated agency and resistance against distressing ads. Drawing on scholarship in postcolonial environmental studies, we use the concept of slow violence to articulate how online targeted advertising inflicts harms that may not be immediately identifiable. CAUTION: This paper includes media that could be triggering, particularly to people with an eating disorder. Please use caution when reading, printing, or disseminating this paper.
Integrated Passive Nonlinear Optical Isolators
Creators: name: White, Alexander D.
name: Ahn, Geun Ho
name: Van Gasse, Kasper
name: Yang, Ki Youl
name: Chang, Lin
name: Bowers, John E.
name: Vučković, Jelena
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Fiber and bulk-optical isolators are widely used to stabilize laser cavities by preventing unwanted feedback. However, their integrated counterparts have been slow to be adopted. While several strategies for on-chip optical isolation have been realized, these rely on either integration of magneto-optic materials or high frequency modulation with acousto-optic or electro-optic modulators. Here, we demonstrate an integrated approach for passively isolating a continuous wave laser using the intrinsically non-reciprocal Kerr nonlinearity in ring resonators. Using silicon nitride as a model platform, we achieve single ring isolation of 17-23dB with 1.8-5.5dB insertion loss, and a cascaded ring isolation of 35dB with 5dB insertion loss. Employing these devices, we demonstrate hybrid integration and isolation with a semi-conductor laser chip.
Projections in duals to Asplund spaces made without Simons' lemma
Creators: name: Cuth, Marek
name: Fabian, Marian
Publisher: name: arXiv
Year: 2013
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics

description: G. Godefroy and the second author of this note proved in 1988 that in duals to Asplund spaces there always exists a projectional resolution of the identity. A few years later, Ch. Stegall succeeded to drop from the original proof a deep lemma of S. Simons. Here, we rewrite the condensed argument of Ch. Stegall in a more transparent and detailed way. We actually show that this technology of Ch. Stegall leads to a bit stronger/richer object ---the so called projectional skeleton--- recently constructed by W. Kubiś, via S. Simons' lemma and with help of elementary submodels from logic.
On the value of the fifth maximal projection constant
Creators: name: Derȩgowska, Beata
name: Fickus, Matthew
name: Foucart, Simon
name: Lewandowska, Barbara
Publisher: name: arXiv
Year: 2022
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 41A65, 41A44, 46B20, 15A42, 42C15

description: Let $λ(m)$ denote the maximal absolute projection constant over real $m$-dimensional subspaces. This quantity is extremely hard to determine exactly, as testified by the fact that the only known value of $λ(m)$ for $m>1$ is $λ(2)=4/3$. There is also numerical evidence indicating that $λ(3)=(1+\sqrt{5})/2$. In this paper, relying on a new construction of certain mutually unbiased equiangular tight frames, we show that $λ(5)\geq 5(11+6\sqrt{5})/59 \approx 2.06919$. This value coincides with the numerical estimation of $λ(5)$ obtained by B. L. Chalmers, thus reinforcing the belief that this is the exact value of $λ(5)$.
EXPTIME-hardness of higher-dimensional Minkowski spacetime
Creators: name: Hirsch, Robin
name: McLean, Brett
Publisher: name: arXiv
Year: 2022
Subjects: subject: Logic (math.LO)
subject: Logic in Computer Science (cs.LO)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: We prove the EXPTIME-hardness of the validity problem for the basic temporal logic on Minkowski spacetime with more than one space dimension. We prove this result for both the lightspeed-or-slower and the slower-than-light accessibility relations (and for both the irreflexive and the reflexive versions of these relations). As an auxiliary result, we prove the EXPTIME-hardness of validity on any frame for which there exists an embedding of the infinite complete binary tree satisfying certain conditions. The proof is by a reduction from the two-player corridor-tiling game.
description: 15 pages
Abundance of second order topology in $C_3$ symmetric two-dimensional insulators
Creators: name: Sødequist, Joachim
name: Petralanda, Urko
name: Olsen, Thomas
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We have screened 71 two-dimensional (2D) materials with $C_3$ symmetry for non-trivial second order topological order and find that 28 compounds exhibit an obstructed atomic limit (OAL). In the case of $C_3$ symmetry, the second order topology can be calculated from bulk symmetry indicator invariants, which predict the value of fractional corner charges in symmetry conserving nanoflakes. The procedure is exemplified by MoS$_2$ in the H-phase, which constitutes a generic example of a 2D OAL material and the predicted fractional corner charges is verified by direct calculations of nanoflakes with armchair edges. We also determine the bulk topological polarization, which always lead to gapless states at zigzag edges and thus deteriorates the concept of fractional corner charges in nanoflakes with zigzag edges that are typically more stable that armchair flakes. We then consider the case of TiCl$_2$, which has vanishing polarization as well as an OAL and we verify that the edge states of nanoflakes with zigzag edges may indeed by passivated such that the edges remain insulating and the corner charges are well defined. For the 28 OAL materials we find that 16 have vanishing polarization and these materials thus constitute a promising starting point for experimental verification of second order topology in a 2D material.
description: 6 pages plus supplementary
Scaling behavior of transverse momenta distributions in hadronic and nuclear collisions
Creators: name: Rybczynski, M.
name: Wlodarczyk, Z.
name: Wilk, G.
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: It has been recently noticed that transverse momenta ($p_T$) distributions observed in high energy production processes exhibit remarkably universal scaling behavior. This is seen when they are in some suitable variable, replacing the usual $p_T$. On the other hand, it is also known that transverse momenta distributions in general follow a power-like Tsallis distribution, rather than an exponential Boltzmann-Gibbs, with a (generally energy dependent) nonextensivity parameter $q$. We now show that it is possible to choose a suitable variable such that $p_T$ distributions of particles produced in proton-proton interactions in a wide energy range can be fitted by the same Tsallis distribution (with the same, energy independent, value of the $q$-parameter). Similar scaling behavior in nucleus-nucleus collisions is also observed. The possible dynamical origin of the q parameter used in these fits will be discussed.
description: 6 pages, 8 figures, presented at the 42 International Symposium on Multiparticle Dynamics (ISMD 2012), Kielce, Poland
Comparison between an exact and a heuristic neural mass model with second order synapses
Creators: name: Clusella, Pau
name: Köksal-Ersöz, Elif
name: Garcia-Ojalvo, Jordi
name: Ruffini, Giulio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: Dynamical Systems (math.DS)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Biological sciences
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Neural mass models (NMMs) are designed to reproduce the collective dynamics of neuronal populations. A common framework for NMMs assumes heuristically that the output firing rate of a neural population can be described by a static nonlinear transfer function (NMM1). However, a recent exact mean-field theory for quadratic integrate-and-fire (QIF) neurons challenges this view by showing that the mean firing rate is not a static function of the neuronal state but follows two coupled nonlinear differential equations (NMM2). Here we analyze and compare these two descriptions in the presence of second-order synaptic dynamics. First, we derive the mathematical equivalence between the two models in the infinitely slow synapse limit, i.e., we show that NMM1 is an approximation of NMM2 in this regime. Next, we evaluate the applicability of this limit in the context of realistic physiological parameter values by analyzing the dynamics of models with inhibitory or excitatory synapses. We show that NMM1 fails to reproduce important dynamical features of the exact model, such as the self-sustained oscillations of an inhibitory interneuron QIF network. Furthermore, in the exact model but not in the limit one, stimulation of a pyramidal cell population induces resonant oscillatory activity whose peak frequency and amplitude increase with the self-coupling gain and the external excitatory input. This may play a role in the enhanced response of densely connected networks to weak uniform inputs, such as the electric fields produced by non-invasive brain stimulation.
Light curves of BSM-induced neutrino echoes in the optically-thin limit
Creators: name: Eskenasy, Ryan
name: Kheirandish, Ali
name: Murase, Kohta
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: High-energy neutrinos from astrophysical transients serve as a probe of neutrino physics beyond the Standard Model. In particular, nonstandard interaction of neutrinos with the cosmic neutrino background or dark matter (DM) may have imprints on not only their spectra but also the arrival and time-delay distributions. Assuming that the interaction occurs at most once during the neutrino propagation, we provide general analytic formulas for light curves of the neutrino echoes induced by BSM. The formulas can be used for constraining neutrino-neutrino scattering, neutrino-DM scattering, and other scattering processes experienced by relativistic particles.
description: 9 pages, 6 figures, version published in PRD, minor changes
Ground state selection by magnon interactions in the fcc antiferromagnet
Creators: name: Schick, R.
name: Götze, O.
name: Ziman, T.
name: Zinke, R.
name: Richter, J.
name: Zhitomirsky, M. E.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the nearest-neighbor Heisenberg antiferromagnet on a face-centered cubic lattice with arbitrary spin S. The model exhibits degenerate classical ground states including two collinear structures AF1 and AF3 described by different propagation vectors that are prime candidates for the quantum ground state. We compute the energy for each of the two states as a function of S using the spin-wave theory that includes magnon-magnon interaction in a self-consistent way and the numerical coupled cluster method. Our results unambiguously demonstrate that quantum fluctuations stabilize the AF1 state for realistic values of spin. Transition to the harmonic spin-wave result, which predicts the AF3 state, takes place only for S > 10. We also study quantum renormalization of the magnon spectra for both states as a function of spin.
description: 10+ pages
Bayes and Frequentism: a Particle Physicist's perspective
Creators: name: Lyons, Louis
Publisher: name: arXiv
Year: 2013
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: High Energy Physics - Experiment (hep-ex)
subject: Methodology (stat.ME)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: In almost every scientific field, an experiment involves collecting data and then analysing it. The analysis stage will often consist in trying to extract some physical parameter and estimating its uncertainty; this is known as Parameter Determination. An example would be the determination of the mass of the top quark, from data collected from high energy proton-proton collisions. A different aim is to choose between two possible hypotheses. For example, are data on the recession speed s of distant galaxies proportional to their distance d, or do they fit better to a model where the expansion of the Universe is accelerating? There are two fundamental approaches to such statistical analyses - Bayesian and Frequentist. This article discusses the way they differ in their approach to probability, and then goes on to consider how this affects the way they deal with Parameter Determination and Hypothesis Testing. The examples are taken from every-day life and from Particle Physics.
The platypus of the quantum channel zoo
Creators: name: Leditzky, Felix
name: Leung, Debbie
name: Siddhu, Vikesh
name: Smith, Graeme
name: Smolin, John A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Information Theory (cs.IT)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Understanding quantum channels and the strange behavior of their capacities is a key objective of quantum information theory. Here we study a remarkably simple, low-dimensional, single-parameter family of quantum channels with exotic quantum information-theoretic features. As the simplest example from this family, we focus on a qutrit-to-qutrit channel that is intuitively obtained by hybridizing together a simple degradable channel and a completely useless qubit channel. Such hybridizing makes this channel's capacities behave in a variety of interesting ways. For instance, the private and classical capacity of this channel coincide and can be explicitly calculated, even though the channel does not belong to any class for which the underlying information quantities are known to be additive. Moreover, the quantum capacity of the channel can be computed explicitly, given a clear and compelling conjecture is true. This "spin alignment conjecture," which may be of independent interest, is proved in certain special cases and additional numerical evidence for its validity is provided. Finally, we generalize the qutrit channel in two ways, and the resulting channels and their capacities display similarly rich behavior. In the companion paper [Phys. Rev. Lett. 130, 200801 (2023); arXiv:2202.08377], we further show that the qutrit channel demonstrates superadditivity when transmitting quantum information jointly with a variety of assisting channels, in a manner unknown before.
description: Comments: 42 pages, 4 figures. v2: matches published version. See also the companion paper arXiv:2202.08377