cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Few-body physics in resonantly interacting ultracold quantum gases
Creators: name: D'Incao, Jose P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We provide a general discussion on the importance of three-body Efimov physics for strongly interacting ultracold quantum gases. Using the adiabatic hyperspherical representation, we discuss a universal classification of three-body systems in terms of the attractive or repulsive character of the effective interactions. The hyperspherical representation leads to a simple and conceptually clear picture for the bound and scattering properties of three-body systems with strong $s$-wave interactions. Using our universal classification scheme, we present a detailed discussion of all relevant ultracold three-body scattering processes using a pathway analysis that makes evident the importance of Efimov physics in determining the energy and scattering length dependence of such processes. This article provides a general overview of the current status of the field and a discussion of various issues relevant to the lifetime and stability of ultracold quantum gases along with universal properties of ultracold, resonantly interacting, few-body systems.
description: 53 pages, 23 figures
title: Qualitative Evaluation of a Collective Impact State-Wide Initiative: Assessing the Collaborative Process of Supporting Resilience by Addressing Childhood Adversity
Creators: name: Koreis, Jessica
Publisher: name: Georgia State University
Year: 2024

description:
The current study is a case study of a developing Collective Impact (CI) initiative to advance the generalizable knowledge of community-based change processes through the CI core components and principles of practice. In addition, this study aimed to inform the initiative of the next steps in adapting and improving its program and its common agenda to prevent and reduce childhood adversity through community-based interventions. Qualitative data comprised of 13 in-depth interviews were utilized to identify themes and assess potential gaps in progress. The findings from the study indicate the importance of meeting all conditions of CI to ensure progression toward population-level changes. The most significant unmet condition found was the lack of a shared measurement system, this absence makes it difficult to ascertain the level of progression toward the other CI conditions and intended goals. Other findings suggest a lack of clear backbone support, coordination, and clear expectations impede systems-level change, development of a shared measurement system, and indicators of change. Common challenges reported point to areas of improvement in CI implementation, backbone support, and community-based change processes for CI initiatives in the early stages of development.
Optimal transport over nonlinear systems via infinitesimal generators on graphs
Creators: name: Elamvazhuthi, Karthik
name: Grover, Piyush
Publisher: name: arXiv
Year: 2016
Subjects: subject: Dynamical Systems (math.DS)
subject: Systems and Control (eess.SY)
subject: Optimization and Control (math.OC)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Mathematics
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Physical sciences
subject: 37M99, 47D03, 93C10, 93C20

description: We present a set-oriented graph-based computational framework for continuous-time optimal transport over nonlinear dynamical systems. We recover provably optimal control laws for steering a given initial distribution in phase space to a final distribution in prescribed finite time for the case of non-autonomous nonlinear control-affine systems, while minimizing a quadratic control cost. The resulting control law can be used to obtain approximate feedback laws for individual agents in a swarm control application. Using infinitesimal generators, the optimal control problem is reduced to a modified Monge-Kantorovich optimal transport problem, resulting in a convex Benamou-Brenier type fluid dynamics formulation on a graph. The well-posedness of this problem is shown to be a consequence of the graph being strongly-connected, which in turn is shown to result from controllability of the underlying dynamical system. Using our computational framework, we study optimal transport of distributions where the underlying dynamical systems are chaotic, and non-holonomic. The solutions to the optimal transport problem elucidate the role played by invariant manifolds, lobe-dynamics and almost-invariant sets in efficient transport of distributions in finite time. Our work connects set-oriented operator-theoretic methods in dynamical systems with optimal mass transportation theory, and opens up new directions in design of efficient feedback control strategies for nonlinear multi-agent and swarm systems operating in nonlinear ambient flow fields.
description: 34 pages, 12 figures. Incorporated reviewers' suggestions
All-dielectric Structure for Trapping Nanoparticles via Light Funneling and Nanofocusing
Creators: name: Jazayeri, Amir M.
name: Mehrany, Khashayar
Publisher: name: arXiv
Year: 2017
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We propose a dielectric structure which focuses the laser light well beyond the diffraction limit and thus considerably enhances the exerted optical trapping force upon dielectric nanoparticles. Although the structure supports a Fabry-Perot resonance, it actually acts as a nanoantenna in that the role of the resonance is to funnel the laser light into the structure. In comparison with the lens illuminating the structure, the proposed structure offers roughly a 10000-fold enhancement in the trapping force - part of this enhancement comes from an 80-fold enhancement in the field intensity, and the remaining comes from a 130-fold enhancement in the normalized gradient of the field intensity (viz. the gradient of the field intensity divided by the field intensity). Also, the proposed structure offers roughly a 100-fold enhancement in the depth of the trapping potential. It is noteworthy that 'self-induced back-action trapping' (SIBA), which has recently been the focus of interest in the context of optical resonators, does not take place in the proposed resonator. In this paper, we also point out some misconceptions about SIBA together with some hitherto unappreciated subtleties of the dipole approximation.
An Analytic Analysis of the Pion Decay Constant in Three-Flavoured Chiral Perturbation Theory
Creators: name: Ananthanarayan, B.
name: Bijnens, Johan
name: Ghosh, Shayan
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: A representation of the two-loop contribution to the pion decay constant in $SU(3)$ chiral perturbation theory is presented. The result is analytic upto the contribution of the three (different) mass sunset integrals, for which an expansion in their external momentum has been taken. We also give an analytic expression for the two-loop contribution to the pion mass based on a renormalized representation and in terms of the physical eta mass. We find an expansion of $F_π$ and $M_π^2$ in the strange quark mass in the isospin limit, and perform the matching of the chiral SU(2) and SU(3) low energy constants. A numerical analysis demonstrates the high accuracy of our representation, and the strong dependence of the pion decay constant upon the values of the low energy constants, especially in the chiral limit. Finally, we present a simplified representation that is particularly suitable for fitting with available lattice data.
description: 34 pages, plain latex, 5 figures; v2 is the version that was published, with further corrections in Eqs. (84) [normalization],(87) and (91) [missing lines inserted] of the published version. Compared to v1, minor changes to the text and typos removed, the notation updated in section 5, new section 7 on lattice fits
Subcritical multiplicative chaos for regularized counting statistics from random matrix theory
Creators: name: Lambert, Gaultier
name: Ostrovsky, Dmitry
name: Simm, Nick
Publisher: name: arXiv
Year: 2016
Subjects: subject: Probability (math.PR)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 60B20 (Primary), 60G15, 60G57 (Secondary)

description: For an $N \times N$ random unitary matrix $U_N$, we consider the random field defined by counting the number of eigenvalues of $U_N$ in a mesoscopic arc of the unit circle, regularized at an $N$-dependent scale $ε_N>0$. We prove that the renormalized exponential of this field converges as $N \to \infty$ to a Gaussian multiplicative chaos measure in the whole subcritical phase. In addition, we show that the moments of the total mass converge to a Selberg-like integral and by taking a further limit as the size of the arc diverges, we establish part of the conjectures in \cite{Ost16}. By an analogous construction, we prove that the multiplicative chaos measure coming from the sine process has the same distribution, which strongly suggests that this limiting object should be universal. The proofs are based on the asymptotic analysis of certain Toeplitz or Fredholm determinants using the Borodin-Okounkov formula or a Riemann-Hilbert problem for integrable operators. Our approach to the $L^{1}$-phase is based on a generalization of the construction in Berestycki \cite{Berestycki15} to random fields which are only \textit{asymptotically} Gaussian. In particular, our method could have applications to other random fields coming from either random matrix theory or a different context.
description: 48 pages. In this updated version we have improved the overall presentation and corrected several typos
On the strongest three-valued paraconsistent logic contained in classical logic and its dual
Creators: name: Middelburg, C. A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Logic in Computer Science (cs.LO)
subject: Logic (math.LO)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: 03B53 (Primary) 03B50, 03B70 (Secondary)

description: LP$^{\supset,\mathsf{F}}$ is a three-valued paraconsistent propositional logic which is essentially the same as J3. It has most properties that have been proposed as desirable properties of a reasonable paraconsistent propositional logic. However, it follows easily from already published results that there are exactly 8192 different three-valued paraconsistent propositional logics that have the properties concerned. In this paper, properties concerning the logical equivalence relation of a logic are used to distinguish LP$^{\supset,\mathsf{F}}$ from the others. As one of the bonuses of focussing on the logical equivalence relation, it is found that only 32 of the 8192 logics have a logical equivalence relation that satisfies the identity, annihilation, idempotent, and commutative laws for conjunction and disjunction. For most properties of LP$^{\supset,\mathsf{F}}$ that have been proposed as desirable properties of a reasonable paraconsistent propositional logic, its paracomplete analogue has a comparable property. In this paper, properties concerning the logical equivalence relation of a logic are also used to distinguish the paracomplete analogue of LP$^{\supset,\mathsf{F}}$ from the other three-valued paracomplete propositional logics with those comparable properties.
description: 17 pages, version that is accepted for publication, there is some text overlap between this paper and arXiv:1508.06899 [cs.LO]
Flavoured $B-L$ Local Symmetry and Anomalous Rare $B$ Decays
Creators: name: Alonso, Rodrigo
name: Cox, Peter
name: Han, Chengcheng
name: Yanagida, Tsutomu T.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider a flavoured $B-L$ gauge symmetry under which only the third generation fermions are charged. Such a symmetry can survive at low energies (~TeV) while still allowing for two superheavy right-handed neutrinos, consistent with neutrino masses via see-saw and leptogenesis. We describe a mechanism for generating Yukawa couplings in this model and also discuss the low-energy phenomenology. Interestingly, the new gauge boson could explain the recent hints of lepton universality violation at LHCb, with a gauge coupling that remains perturbative up to the Planck scale. Finally, we discuss more general $U(1)$ symmetries and show that there exist only two classes of vectorial $U(1)$ that are both consistent with leptogenesis and remain phenomenologically viable at low-energies.
description: 7 pages, 3 figures; v2: version published in PLB
On conservation laws for the supersymmetric sigma model
Creators: name: Branding, Volker
Publisher: name: arXiv
Year: 2017
Subjects: subject: Differential Geometry (math.DG)
subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 58E20, 53C27, 70S10

description: We derive conservation laws for Dirac-harmonic maps and their extensions to manifolds that have isometries, where we mostly focus on the spherical case. In addition, we discuss several geometric and analytic applications of the latter.
On ${\rm mod}~p$ $A_p$-spaces
Creators: name: Huang, Ruizhi
name: Wu, Jie
Publisher: name: arXiv
Year: 2017
Subjects: subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 55P45, 55S25, 55P15, 55S05, 55N15

description: We prove a necessary condition for the existence of the $A_p$-structure on ${\rm mod}~p$ spaces, and also derive a simple proof for the finiteness of the number of ${\rm mod}~p$ $A_p$-spaces of given rank. As a direct application, we compute a list of possible types of rank $3$ ${\rm mod}~3$ homotopy associative $H$-spaces.
Quantum quench dynamics of the attractive one-dimensional Bose gas via the coordinate Bethe ansatz
Creators: name: Zill, Jan C.
name: Wright, Tod M.
name: Kheruntsyan, Karen V.
name: Gasenzer, Thomas
name: Davis, Matthew J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We use the coordinate Bethe ansatz to study the Lieb-Liniger model of a one-dimensional gas of bosons on a finite-sized ring interacting via an attractive delta-function potential. We calculate zero-temperature correlation functions for seven particles in the vicinity of the crossover to a localized solitonic state and study the dynamics of a system of four particles quenched to attractive interactions from the ideal-gas ground state. We determine the time evolution of correlation functions, as well as their temporal averages, and discuss the role of bound states in shaping the postquench correlations and relaxation dynamics.
description: v1: Original submission to SciPost Physics. v2: Improvements to text based on referee comments
Disentangling Hype from Practicality: On Realistically Achieving Quantum Advantage
Creators: name: Hoefler, Torsten
name: Haener, Thomas
name: Troyer, Matthias
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Data Structures and Algorithms (cs.DS)
subject: Performance (cs.PF)
subject: Popular Physics (physics.pop-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Quantum computers offer a new paradigm of computing with the potential to vastly outperform any imagineable classical computer. This has caused a gold rush towards new quantum algorithms and hardware. In light of the growing expectations and hype surrounding quantum computing we ask the question which are the promising applications to realize quantum advantage. We argue that small data problems and quantum algorithms with super-quadratic speedups are essential to make quantum computers useful in practice. With these guidelines one can separate promising applications for quantum computing from those where classical solutions should be pursued. While most of the proposed quantum algorithms and applications do not achieve the necessary speedups to be considered practical, we already see a huge potential in material science and chemistry. We expect further applications to be developed based on our guidelines.
Einstein's Geometrical Versus Feynman's Quantum-Field Approaches to Gravity Physics: Testing by Modern Multimessenger Astronomy
Creators: name: Baryshev, Yurij
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: Modern multimessenger astronomy delivers unique opportunity for performing crucial observations that allow for testing the physics of the gravitational interaction. These tests include detection of gravitational waves by advanced LIGO-Virgo antennas, Event Horizon Telescope observations of central relativistic compact objects (RCO) in active galactic nuclei (AGN), X-ray spectroscopic observations of Fe K line in AGN, Galactic X-ray sources measurement of masses and radiuses of neutron stars, quark stars, and other RCO. A very important task of observational cosmology is to perform large surveys of galactic distances independent on cosmological redshifts for testing the nature of the Hubble law and peculiar velocities. Forthcoming multimessenger astronomy, using such facilities as advanced LIGO-Virgo, Event Horizon Telescope (EHT), ALMA, WALLABY, JWST, EUCLID, and THESEUS, can elucidate the relation between Einstein's geometrical and Feynman's quantum-field approaches to gravity physics and deliver a new possibilities for unification of gravitation with other fundamental quantum physical interactions.
description: 102 pages, 1 figure, 300 references (alphabetic order), text updated and extended, published in journal Universe 18 November 2020
Dual meson condensates in the Polyakov-loop extended linear sigma model
Creators: name: Zhang, Zhao
name: Lu, Haipeng
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Dual meson condensates as possible order parameters for deconfinement are investigated in a Polyakov-loop enhanced linear sigma model of QCD at both zero and finite isospin chemical potential $μ_I$. We find that the rapid rise of the dual sigma condensate (corresponding to the dressed Polyakov-loop) with $T$ is driven by the chiral transition, no matter whether the Polyakov-loop dynamics is included or not. For $μ_I>m_π/2$, the dual sigma condensate shows abnormal thermal behavior which even decreases with $T$ below the melting temperature $T_c^{I_3}$ of pion superfluidity; On the other hand, even the dual pion condensate always increases with $T$, its maximum slope locates exactly at $T_c^{I_3}$ rather than the deconfinement temperature $T_c^{P}$ determined by the Polyakov-loop. All these are qualitatively consistent with the previous results obtained in the Nambu-Jona-Lasinio type models. The dual vector meson condensate for $μ_I>m_π/2$ is also calculated. This quantity is more sensitive to the chiral transition when taking into account the Dirac-sea contribution. Our study further suggests that it should be cautious to use dual observables to indicate the deconfinement transition, especially in QCD models.
description: 9 pages,7 figures, discussions added, references added, typos corrected
Asymptotic behaviour of the fifth Painlevé transcendents in the space of initial values
Creators: name: Joshi, Nalini
name: Radnović, Milena
Publisher: name: arXiv
Year: 2017
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 34M55, 34M30

description: We study the asymptotic behaviour of the solutions of the fifth Painlevé equation as the independent variable approaches zero and infinity in the space of initial values. We show that the limit set of each solution is compact and connected and, moreover, that any solution with the essential singularity at zero has an infinite number of poles and zeroes, and any solution with the essential singularity at infinity has infinite number of poles and takes value $1$ infinitely many times.
description: 36 pages, 5 figures. arXiv admin note: text overlap with arXiv:1412.3541
Kinematic Basis of Emergent Energetics of Complex Dynamics
Creators: name: Qian, Hong
name: Cheng, Yu-Chen
name: Yang, Ying-Jen
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Physics (physics.gen-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Stochastic kinematic description of a complex dynamics is shown to dictate an energetic and thermodynamic structure. An energy function $φ(x)$ emerges as the limit of the generalized, nonequilibrium free energy of a Markovian dynamics with vanishing fluctuations. In terms of the $\nablaφ$ and its orthogonal field $γ(x)\perp\nablaφ$, a general vector field $b(x)$ can be decomposed into $-D(x)\nablaφ+γ$, where $\nabla\cdot\big(ω(x)γ(x)\big)=$ $-\nablaωD(x)\nablaφ$. The matrix $D(x)$ and scalar $ω(x)$, two additional characteristics to the $b(x)$ alone, represent the local geometry and density of states intrinsic to the statistical motion in the state space at $x$. $φ(x)$ and $ω(x)$ are interpreted as the emergent energy and degeneracy of the motion, with an energy balance equation $dφ(x(t))/dt=γD^{-1}γ-bD^{-1}b$, reflecting the geometrical $\|D\nablaφ\|^2+\|γ\|^2=\|b\|^2$. The partition function employed in statistical mechanics and J. W. Gibbs' method of ensemble change naturally arise; a fluctuation-dissipation theorem is established via the two leading-order asymptotics of entropy production as $ε\to 0$. The present theory provides a mathematical basis for P. W. Anderson's emergent behavior in the hierarchical structure of complexity science.
description: 7 pages
Stochastic evolution equations for large portfolios of stochastic volatility models
Creators: name: Hambly, Ben
name: Kolliopoulos, Nikolaos
Publisher: name: arXiv
Year: 2017
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60H15 (primary), 60H07, 91G80 (secondary)

description: We consider a large market model of defaultable assets in which the asset price processes are modelled as Heston-type stochastic volatility models with default upon hitting a lower boundary. We assume that both the asset prices and their volatilities are correlated through systemic Brownian motions. We are interested in the loss process that arises in this setting and we prove the existence of a large portfolio limit for the empirical measure process of this system. This limit evolves as a measure valued process and we show that it will have a density given in terms of a solution to a stochastic partial differential equation of filtering type in the two-dimensional half-space, with a Dirichlet boundary condition. We employ Malliavin calculus to establish the existence of a regular density for the volatility component, and an approximation by models of piecewise constant volatilities combined with a kernel smoothing technique to obtain existence and regularity for the full two-dimensional filtering problem. We are able to establish good regularity properties for solutions, however uniqueness remains an open problem.
description: Last update: An erratum to this paper is available at: Arxiv:1905.04397
Acoustic geometry obtained through the perturbation of the Bernoulli's constant
Creators: name: Datta, Satadal
name: Shaikh, Md Arif
name: Das, Tapas K
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: For accretion onto astrophysical black holes, we demonstrate that linear perturbation of Bernoulli's constant defined for an inviscid irrotational adiabatic flow of perfect ideal fluid gives rise to phenomena of analogue gravity. The formulation of our work is done in the Newtonian framework and also within the General relativistic framework, i.e., considering a static spacetime background, as well. The resulting structure of the analogue acoustic metric is similar to the acoustic metric found in perturbing velocity potential and mass accretion rate.
description: 22 pages, no figures
Type II-P Supernova Progenitor Star Initial Masses and SN 2020jfo: Direct Detection, Light Curve Properties, Nebular Spectroscopy, and Local Environment
Creators: name: Kilpatrick, Charles D.
name: Izzo, Luca
name: Bentley, Rory O.
name: Chambers, Kenneth C.
name: Coulter, David A.
name: Drout, Maria R.
name: de Boer, Thomas
name: Foley, Ryan J.
name: Gall, Christa
name: Halford, Melissa R.
name: Jones, David O.
name: Langeroodi, Danial
name: Lin, Chien-Cheng
name: Magnier, Eugene A.
name: McGill, Peter
name: O'Grady, Anna J. G.
name: Pan, Yen-Chen
name: Ramirez-Ruiz, Enrico
name: Rest, Armin
name: Swift, Jonathan J.
name: Tinyanont, Samaporn
name: Villar, V. Ashley
name: Wainscoat, Richard J.
name: Wasserman, Amanda Rose
name: Yadavalli, S. Karthik
name: Yang, Grace
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present optical, ultraviolet, and infrared data of the type II supernova (SN II) 2020jfo at 14.5 Mpc. This wealth of multiwavelength data allows to compare different metrics commonly used to estimate progenitor masses of SN II for the same object. Using its early light curve, we infer SN 2020jfo had a progenitor radius of $\approx$700 $R_{\odot}$, consistent with red supergiants of initial mass $M_{\rm ZAMS}=$11-13 $M_{\odot}$. The decline in its late-time light curve is best fit by a ${}^{56}$Ni mass of 0.018$\pm$0.007 $M_{\odot}$ consistent with that ejected from SN II-P with $\approx$13 $M_{\odot}$ initial mass stars. Early spectra and photometry do not exhibit signs of interaction with circumstellar matter, implying that SN 2020jfo experienced weak mass loss within the final years prior to explosion. Our spectra at $>$250 days are best fit by models from 12 $M_{\odot}$ initial mass stars. We analyzed integral field unit spectroscopy of the stellar population near SN 2020jfo, finding its massive star population had a zero age main sequence mass of 9.7$\substack{+2.5\\-1.3} M_{\odot}$. We identify a single counterpart in pre-explosion imaging and find it has an initial mass of at most $7.2\substack{+1.2\\-0.6} M_{\odot}$. We conclude that the inconsistency between this mass and indirect mass indicators from SN 2020jfo itself is most likely caused by extinction with $A_{V}=2$-3 mag due to matter around the progenitor star, which lowered its observed optical luminosity. As SN 2020jfo did not exhibit extinction at this level or evidence for interaction with circumstellar matter between 1.6-450 days from explosion, we conclude that this material was likely confined within $\approx$3000 $R_{\odot}$ from the progenitor star.
description: 31 pages, 12 figures, accepted to MNRAS
On The Negativity of Ricci Curvatures of Complete Conformal Metrics
Creators: name: Han, Qing
name: Shen, Weiming
Publisher: name: arXiv
Year: 2017
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: A version of the singular Yamabe problem in bounded domains yields complete conformal metrics with negative constant scalar curvatures. In this paper, we study whether these metrics have negative Ricci curvatures. Affirmatively, we prove that these metrics indeed have negative Ricci curvatures in bounded convex domains in the Euclidean space. On the other hand, we provide a general construction of domains in compact manifolds and demonstrate that the negativity of Ricci curvatures does not hold if the boundary is close to certain sets of low dimension. The expansion of the Green's function and the positive mass theorem play essential roles in certain cases.
Seismic wave propagation in icy ocean worlds
Creators: name: Stähler, Simon C.
name: Panning, Mark P.
name: Vance, Steve D.
name: Lorenz, Ralph
name: van Driel, Martin
name: Nissen-Meyer, Tarje
name: Kedar, Sharon
Publisher: name: arXiv
Year: 2017
Subjects: subject: Geophysics (physics.geo-ph)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Seismology was developed on Earth and shaped our model of the Earth's interior over the 20th century. With the exception of the Philae lander, all in situ extraterrestrial seismological effort to date was limited to other terrestrial planets. All have in common a rigid crust above a solid mantle. The coming years may see the installation of seismometers on Europa, Titan and Enceladus, so it is necessary to adapt seismological concepts to the setting of worlds with global oceans covered in ice. Here we use waveform analyses to identify and classify wave types, developing a lexicon for icy ocean world seismology intended to be useful to both seismologists and planetary scientists. We use results from spectral-element simulations of broadband seismic wavefields to adapt seismological concepts to icy ocean worlds. We present a concise naming scheme for seismic waves and an overview of the features of the seismic wavefield on Europa, Titan, Ganymede and Enceladus. In close connection with geophysical interior models, we analyze simulated seismic measurements of Europa and Titan that might be used to constrain geochemical parameters governing the habitability of a sub-ice ocean.
description: 47 pages, 14 figures, accepted for publication in JGR Planets
Reconstruction of stochastic 3-D signals with symmetric statistics from 2-D projection images motivated by cryo-electron microscopy
Creators: name: Xu, Nan
name: Doerschuk, Peter C
Publisher: name: arXiv
Year: 2017
Subjects: subject: Applications (stat.AP)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Cryo-electron microscopy provides 2-D projection images of the 3-D electron scattering intensity of many instances of the particle under study (e.g., a virus). Both symmetry (rotational point groups) and heterogeneity are important aspects of biological particles and both aspects can be combined by describing the electron scattering intensity of the particle as a stochastic process with a symmetric probability law and therefore symmetric moments. A maximum likelihood estimator implemented by an expectation-maximization algorithm is described which estimates the unknown statistics of the electron scattering intensity stochastic process from images of instances of the particle. The algorithm is demonstrated on the bacteriophage HK97 and the virus N$ω$V. The results are contrasted with existing algorithms which assume that each instance of the particle has the symmetry rather than the less restrictive assumption that the probability law has the symmetry.
description: 16 pages, 10 figures
Focusing and sorting of ellipsoidal magnetic particles in microchannels
Creators: name: Matsunaga, Daiki
name: Meng, Fanlong
name: Zoettl, Andreas
name: Golestanian, Ramin
name: Yeomans, Julia M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We present a simple method to control the position of ellipsoidal magnetic particles in microchannel Poiseuille flow using a static uniform magnetic field. The magnetic field is utilized to pin the particle orientation, and the hydrodynamic interactions between ellipsoids and channel walls allow control of the transverse position of the particles. We employ a far-field hydrodynamic theory and simulations using the boundary element method and Brownian dynamics to show how magnetic particles can be focussed and segregated by size and shape. This is of importance for particle manipulation in lab-on-a-chip devices.
Fermionic continuous spin gauge field in (A)dS space
Creators: name: Metsaev, R. R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Fermionic continuous spin field propagating in (A)dS space-time is studied. Gauge invariant Lagrangian formulation for such fermionic field is developed. Lagrangian of the fermionic continuous spin field is constructed in terms of triple gamma-traceless tensor-spinor Dirac fields, while gauge symmetries are realized by using gamma-traceless gauge transformation parameters. It is demonstrated that partition function of fermionic continuous spin field is equal to one. Modified de Donder gauge condition that considerably simplifies analysis of equations of motion is found. Decoupling limits leading to arbitrary spin massless, partial-massless, and massive fermionic fields are studied.
description: 13 pages, v2: Footnotes 1,5,6 and reference added. Alternative form of formulas (3.37),(3.38) is given
Spontaneous breakdown of charge in the MSSM and in the NMSSM: Possibilities and Implications
Creators: name: Beuria, Jyotiranjan
name: Datta, AseshKrishna
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the possibilities and the implications of a spontaneous breakdown of charge in the MSSM and in the $Z_3$-symmetric NMSSM. The breakdown is triggered by the charged states of the Higgs doublets acquiring vacuum expectation values. In the MSSM, it is known that the presence of a charge conserving minimum for the tree-level Higgs potential precludes a deeper (global) charge-breaking minimum. We find that the inclusion of radiative correction to the potential does not alter the situation while a deeper charge-conserving minimum could arise, albeit with no major practical consequences. In the NMSSM scenario, a charge-breaking global minimum, with or without an accompanying charge-conserving deeper minimum, could appear even with the tree-level Higgs potential thanks to the presence of a charge-neutral scalar state which transforms as a singlet under the Standard Model gauge group. Use of the NMSSM Higgs potential that includes both quantum and thermal corrections and the requirement of a viable (stable or long-lived) vacuum that breaks the electroweak symmetry, along with its compatibility with the latest Higgs data, lead to nontrivial constraints on the NMSSM parameter space.
description: 27 pages, 8 figures, 1 table; matches with published version
Synthesis and materialization of a reaction-diffusion French flag pattern
Creators: name: Zadorin, Anton
name: Rondelez, Yannick
name: Gines, Guillaume
name: Dilhas, Vadim
name: Urtel, Georg
name: Zambrano, Adrian
name: Galas, Jean-Christophe
name: Estevez-Torres, Andre
Publisher: name: arXiv
Year: 2017
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: During embryo development, patterns of protein concentration appear in response to morphogen gradients. These patterns provide spatial and chemical information that directs the fate of the underlying cells. Here, we emulate this process within non-living matter and demonstrate the autonomous structuration of a synthetic material. Firstly, we use DNA-based reaction networks to synthesize a French flag, an archetypal pattern composed of three chemically-distinct zones with sharp borders whose synthetic analogue has remained elusive. A bistable network within a shallow concentration gradient creates an immobile, sharp and long-lasting concentration front through a reaction-diffusion mechanism. The combination of two bistable circuits generates a French flag pattern whose 'phenotype' can be reprogrammed by network mutation. Secondly, these concentration patterns control the macroscopic organization of DNA-decorated particles, inducing a French flag pattern of colloidal aggregation. This experimental framework could be used to test reaction-diffusion models and fabricate soft materials following an autonomous developmental program.
description: Accepted version after embargo. Fig 4 now show materialization of a French flag pattern. Supplementary materials have been substantially improved
Synthesis of Tongue Motion and Acoustics from Text using a Multimodal Articulatory Database
Creators: name: Steiner, Ingmar
name: Maguer, Sébastien Le
name: Hewer, Alexander
Publisher: name: arXiv
Year: 2016
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: We present an end-to-end text-to-speech (TTS) synthesis system that generates audio and synchronized tongue motion directly from text. This is achieved by adapting a 3D model of the tongue surface to an articulatory dataset and training a statistical parametric speech synthesis system directly on the tongue model parameters. We evaluate the model at every step by comparing the spatial coordinates of predicted articulatory movements against the reference data. The results indicate a global mean Euclidean distance of less than 2.8 mm, and our approach can be adapted to add an articulatory modality to conventional TTS applications without the need for extra data.
Sound waves and vortices in a polarized relativistic fluid
Creators: name: Montenegro, David
name: Tinti, Leonardo
name: Torrieri, Giorgio
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We extend the effective theory approach to the ideal fluid limit where the polarization of the fluid is non-zero. After describing and motivating the equations of motion, we expand them around the hydrostatic limit, obtaining the sound wave and vortex degrees of freedom. We discuss how the presence of polarization affects the stability and causality of the ideal fluid limit.
description: Version accepted for publication, Phys.Rev.D
Effective impurity behavior emergent from non-Hermitian proximity effect
Creators: name: Wu, Deguang
name: Chen, Jiasong
name: Su, Wei
name: Wang, Rui
name: Wang, Baigeng
name: Xing, D. Y.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Non-Hermitian boundaries commonly take place in many open quantum systems locally coupled to a surrounding environment. Here, we reveal a type of non-Hermitian effect induced by non-Hermitian boundaries, the non-Hermitian proximity effect (NHPE), which describes the penetration of non-Hermiticity from the boundary into the bulk. For gapped quantum systems, the NHPE generates in-gap states with imaginary eigenenergies, termed ``imaginary in-gap states". The imaginary in-gap states are localized at the system boundary and decay into the bulk, analogous to the behaviors of the conventional impurity states. However, in contrast to impurity states, the imaginary in-gap states exhibit distinct dynamical behaviors under time-evolution. Moreover, they are physically manifested as corner modes under open boundaries, as a combined result of the non-Hermitian skin effect (NHSE) and NHPE. These results not only uncover implicit similarities between quantum systems with non-Hermitian boundaries and impurity physics, but also point to intriguing non-Hermitian phenomena broadly relevant to open quantum systems.
description: 10 pages, 5 figures
Fast quantitative MRI as a nonlinear tomography problem
Creators: name: Sbrizzi, Alessandro
name: van der Heide, Oscar
name: Cloos, Martijn
name: van der Toorn, Annette
name: Hoogduin, Hans
name: Luijten, Peter R.
name: Berg, Cornelis A. T. van den
Publisher: name: arXiv
Year: 2017
Subjects: subject: Applied Physics (physics.app-ph)
subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Quantitative Magnetic Resonance Imaging (MRI) is based on a two-steps approach: estimation of the magnetic moments distribution inside the body, followed by a voxel-by-voxel quantification of the human tissue properties. This splitting simplifies the computations but poses several constraints on the measurement process, limiting its efficiency. Here, we perform quantitative MRI as a one step process; signal localization and parameter quantification are simultaneously obtained by the solution of a large scale nonlinear inversion problem based on first-principles. As a consequence, the constraints on the measurement process can be relaxed and acquisition schemes that are time efficient and widely available in clinical MRI scanners can be employed. We show that the nonlinear tomography approach is applicable to MRI and returns human tissue maps from very short experiments. Keywords: MR-STAT, quantitative MRI, nonlinear tomography, MR Fingerprinting, large scale inversion.
Large-scale network motif analysis using compression
Creators: name: Bloem, Peter
name: de Rooij, Steven
Publisher: name: arXiv
Year: 2017
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: We introduce a new method for finding network motifs: interesting or informative subgraph patterns in a network. Subgraphs are motifs when their frequency in the data is high compared to the expected frequency under a null model. To compute this expectation, a full or approximate count of the occurrences of a motif is normally repeated on as many as 1000 random graphs sampled from the null model; a prohibitively expensive step. We use ideas from the Minimum Description Length (MDL) literature to define a new measure of motif relevance. With our method, samples from the null model are not required. Instead we compute the probability of the data under the null model and compare this to the probability under a specially designed alternative model. With this new relevance test, we can search for motifs by random sampling, rather than requiring an accurate count of all instances of a motif. This allows motif analysis to scale to networks with billions of links.
Imposing higher-level Structure in Polyphonic Music Generation using Convolutional Restricted Boltzmann Machines and Constraints
Creators: name: Lattner, Stefan
name: Grachten, Maarten
name: Widmer, Gerhard
Publisher: name: arXiv
Year: 2016
Subjects: subject: Sound (cs.SD)
subject: Artificial Intelligence (cs.AI)
subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: We introduce a method for imposing higher-level structure on generated, polyphonic music. A Convolutional Restricted Boltzmann Machine (C-RBM) as a generative model is combined with gradient descent constraint optimisation to provide further control over the generation process. Among other things, this allows for the use of a "template" piece, from which some structural properties can be extracted, and transferred as constraints to the newly generated material. The sampling process is guided with Simulated Annealing to avoid local optima, and to find solutions that both satisfy the constraints, and are relatively stable with respect to the C-RBM. Results show that with this approach it is possible to control the higher-level self-similarity structure, the meter, and the tonal properties of the resulting musical piece, while preserving its local musical coherence.
description: 31 pages, 11 figures
Galactic binary science with the new LISA design
Creators: name: Cornish, Neil
name: Robson, Travis
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Building on the great success of the LISA Pathfinder mission, the outlines of a new LISA mission design were laid out at the $11^{\rm th}$ International LISA Symposium in Zurich. The revised design calls for three identical spacecraft forming an equilateral triangle with 2.5 million kilometer sides, and two laser links per side delivering full polarization sensitivity. With the demonstrated Pathfinder performance for the disturbance reduction system, and a well studied design for the laser metrology, it is anticipated that the new mission will have a sensitivity very close to the original LISA design. This implies that the mid-band performance, between 0.5 mHz and 3 mHz, will be limited by unresolved signals from compact binaries in our galaxy. Here we use the new LISA design to compute updated estimates for the galactic confusion noise, the number of resolvable galactic binaries, and the accuracy to which key parameters of these systems can be measured.
description: 4 pages, 5 figures. Prepared for the proceedings of the 11th International LISA Symposium. Typo corrected in Equation (1). Thanks to Latham Boyle for catching this
Low-energy tail of the spectral density for a particle interacting with a quantum phonon bath
Creators: name: Kim, Donghwan
name: Halperin, Bertrand I.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We describe two approximation methods designed to capture the leading behavior of the low-energy tail of the momentum-dependent spectral density $A(\mathbf{k}, E)$ and the tunneling density of states $D(E)$ for an injected particle, such as an electron or an exciton, interacting with a bath of phonons at a non-zero initial temperature $T$, including quantum corrections due to the non-zero frequencies of the relevant phonons. In our imaginary-time-dependent Hartree (ITDH) approximation, we consider a situation where the particle is injected into a specified coherent state of the phonon system, and we show how one can use the ITDH approximation to obtain the correlation function $C(τ)$ for that initial state. The thermal average $C(τ)$ is obtained, in principle, by integrating the result over all possible initial phonon coherent states, weighted by a thermal distribution. However, in the low-energy tail, one can obtain a good first approximation by considering only initial states near the one that maximizes the integrand. Our second approximation, the fixed-wave-function (FWF) approximation, assumes that the wave function of the injected particle evolves instantaneously to a wave function which then is independent of time, while the phonon system continues to evolve due to interaction with the particle. We discuss how to invert the Laplace transform and how to obtain $A(\mathbf{k},E)$ as well as $D(E)$ from the imaginary-time analysis. The FWF approximation is used to calculate $D(E)$ for a one-dimensional continuum model of a particle interacting with acoustic phonons, and effects due to the quantum motion of phonons are observed. In the classical phonon limit, the dominant behaviors of both the ITDH and FWF approximations in the low-energy tail reduce to that found in the past for a particle in a random potential with a Gaussian statistical distribution.
description: Manuscript submitted to Physical Review B for inclusion in the collection honoring Emmanuel Rashba