cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Anderson-like impurity in the one-dimensional t-J model: Formation of local states and magnetic behavior
Creators: name: Frahm, Holger
name: Palacios, Guillaume
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2006
Subjects: subject: open t-J chain
subject: Anderson-like impurity
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: We consider an integrable model describing an Anderson-like impurity coupled to an open t-J chain. Both the hybridization (i.e., its coupling to bulk chain) and the local spectrum can be controlled without breaking the integrability of the model. As the hybridization is varied, holon and spinon bound states appear in the many body ground state. Based on the exact solution we study the state of the impurity and its contribution to thermodynamic quantities as a function of an applied magnetic field. Kondo behavior in the magnetic response of the impurity can be observed provided that its parameters have been adjusted properly to the energy scales of the holon and spinon excitations of the one-dimensional bulk.
Harmonic N=2 mechanics
Creators: name: Galajinsky, Anton
name: Lechtenfeld, Olaf
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2009
Subjects: subject: boson-fermion coupling
subject: physical symmetry requirements
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: N=2 superconformal many-body quantum mechanics in arbitrary dimensions is governed by a single scalar prepotential which determines the bosonic potential and the boson-fermion couplings. We present a special class of such models, for which the bosonic potential is absent. They are classified by homogeneous harmonic functions subject to physical symmetry requirements, such as translation, rotation and permutation invariance. The central charge is naturally quantized. We provide some examples for systems of identical particles in any dimension.
Kink-antikink collisions in the $ϕ^8$ model: short-range to long-range journey
Creators: name: Bazeia, Dionisio
name: Campos, João G. F.
name: Mohammadi, Azadeh
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: We studied kink-antikink collisions in (1+1)-dimensional spacetime for all $Z_2$ symmetric $ϕ^8$ models with four degenerate minima. Such a polynomial model has only one free parameter, allowing us to conduct an exhaustive analysis. We performed detailed simulations in all three sectors of the model. We observed resonance windows from both localized and delocalized modes, as well as a sector change with the formation of additional kink-antikink pairs. Furthermore, we were able to show how collisions are modified when two quadratic minima merge into a quartic one, causing the kinks to acquire a long-range character. We demonstrated that when the tail not facing the opposing kink is long-range, incoming kinks and antikinks decay directly into radiation, as suggested in \cite{campos2021interaction}, by forming a large number of small kink-antikink pairs. Finally, we briefly discussed whether our analysis could be generalized to other polynomial models.
title: A search for intermediate-mass black holes in compact stellar systems through optical emissions from tidal disruption events
Creators: name: Pomeroy, Richard
Publisher: name: University of Central Lancashire
Year: 2023

description: In this project, we have taken two separate data sets, and applied them to a search for tidal disruption events (TDEs), to provide evidence for the existence of intermediate-mass black holes (IMBH). The search was performed primarily on the optical archives of the Zwicky Transient facility (ZTF), using light curves and alerts produced by the facility. Follow-up and contextual imaging were also carried out using PanSTARRS and HST archives. The data sets were based on compact stellar system (CSS) positions, covering the mass / radius space from globular clusters through to dwarf elliptical galaxies, with one data set consolidated from literature CSS positions, and the other from notional GC/CSS populations hosted around massive galaxies at distance 2 ¤ D ¤ 120 Mpc. We discussed the nature of CSS environments, especially considering the low-mass clusters, or ultra-compact dwarf (UCD), end of what is considered a composite population, with the expectation that any TDEs observed in aged cluster populations would involve IMBH and white dwarfs. The larger mass systems, nominally referred to as compact ellipticals (cEs), derived from tidally threshed larger galaxies, are more likely to host IMBH of higher mass, or even super-massive black holes (SMBH), but no strong evidence was found to preclude TDEs also being observed in these systems. Despite analysis of the archives covering a period of approximately 42 months, no evidence of optical TDE transient signatures was found through either inspection of light curves and transient alerts at known CSS positions, or alerts in the periphery of host galaxies. A statistical analysis was carried out on the second data set, quantifying the sample size and visibility using the globular cluster luminosity function (GCLF). From this result we conclude that the upper limit for the rate of TDEs in CSS is nTDE,Vis Æ 10_6yr_1gal_1 which is two orders of magnitude below the theoretical TDE rate involving SMBH interacting with solar mass main sequence stars in the nucleus of massive galaxies.
SU(2) reduction in N=4 supersymmetric mechanics
Creators: name: Krivonos, Sergey
name: Lechtenfeld, Olaf
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2009
Subjects: subject: Hamiltonian reduction
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: We perform an su(2) Hamiltonian reduction of the general su(2)-invariant action for a self-coupled (4, 4, 0) supermultiplet. As a result, we elegantly recover the N=4 supersymmetric mechanics with spin degrees of freedom which was recently constructed in [S. Fedoruk, E. Ivanov, and O. Lechtenfeld, Phys. Rev. D 79, 105015 (2009)]. This observation underscores the exceptional role played by the root supermultiplet in N=4 supersymmetric mechanics.
Protoplanetary migration in non-isothermal discs with turbulence driven by stochastic forcing
Creators: name: Pierens, A.
name: Baruteau, C.
name: Hersant, F.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Low-mass objects embedded in isothermal protoplanetary discs are known to suffer rapid inward Type I migration. In non-isothermal discs, recent work has shown that a decreasing radial profile of the disc entropy can lead to a strong positive corotation torque which can significantly slow down or reverse Type I migration in laminar viscous disc models. It is not clear however how this picture changes in turbulent disc models. The aim of this study is to examine the impact of turbulence on the torque experienced by a low-mass planet embedded in a non-isothermal protoplanetary disc. We particularly focus on the role of turbulence on the corotation torque whose amplitude depends on the efficiency of diffusion processes in the planet's horseshoe region. We performed 2D numerical simulations using a grid-based hydrodynamical code in which turbulence is modelled as stochastic forcing. In order to provide estimations for the viscous and thermal diffusion coefficients as a function of the amplitude of turbulence, we first set up non-isothermal disc models for different values of the amplitude of the turbulent forcing. We then include a low-mass planet and determine the evolution of its running time-averaged torque. We show that in non-isothermal discs, the entropy-related corotation torque can indeed remain unsaturated in the presence of turbulence. For turbulence amplitudes that do not strongly affect the disc temperature profile, we find that the running time-averaged torque experienced by an embedded protoplanet is in fairly good agreement with laminar disc models with appropriate values for the thermal and viscous diffusion coefficients. In discs with turbulence driven by stochastic forcing, the corotation torque therefore behaves similarly as in laminar viscous discs and can be responsible for significantly slowing down or reversing Type I migration.
description: accepted for publication in MNRAS
Magnetic charge and black hole supersymmetric quantum statistical relation
Creators: name: Genolini, Pietro Benetti
name: Toldo, Chiara
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the thermodynamics in the BPS limit of AdS black holes realizing the topological twist. We use a limiting procedure that allows us to reach the extremal point along a trajectory in the space of supersymmetric Euclidean solutions. We show that on this space we can write a quantum statistical relation, which is well-defined in the BPS limit and relies on imposing a suitable constraint among the chemical potentials, due to supersymmetry and regularity. We stress the importance of this in relating the thermal partition function of the dual field theory to the topologically twisted index.
description: 18 pages; v2: added comments on renormalization and relation with literature
Insights into Pre-Enrichment of Star Clusters and Self-Enrichment of Dwarf Galaxies from their Intrinsic Metallicity Dispersions
Creators: name: Leaman, Ryan
Publisher: name: arXiv
Year: 2012
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Star clusters are known to have smaller intrinsic metallicity spreads than dwarf galaxies due to their shorter star formation timescales. Here we use individual spectroscopic [Fe/H] measurements of stars in 19 Local Group dwarf galaxies, 13 Galactic open clusters, and 49 globular clusters to show that star cluster and dwarf galaxy linear metallicity distributions are binomial in form, with all objects showing strong correlations between their mean linear metallicity $\bar{Z}$ and intrinsic spread in metallicity $σ(Z)^{2}$. A plot of $σ(Z)^{2}$ versus $\bar{Z}$ shows that the correlated relationships are offset for the dwarf galaxies from the star clusters. The common binomial nature of these linear metallicity distributions can be explained with a simple inhomogeneous chemical evolution model (e.g., Oey 2000), where the star cluster and dwarf galaxy behaviour in the $σ(Z)^{2}-\bar{Z}$ diagram is reproduced in terms of the number of enrichment events, covering fraction, and intrinsic size of the enriched regions. The inhomogeneity of the self-enrichment sets the slope for the observed dwarf galaxy $σ(Z)^{2}-\bar{Z}$ correlation. The offset of the star cluster sequence from that of the dwarf galaxies is due to pre-enrichment, and the slope of the star cluster sequence represents the remnant signature of the self-enriched history of their host galaxies. The offset can be used to separate star clusters from dwarf galaxies without a priori knowledge of their luminosity or dynamical mass. The application of the inhomogeneous model to the $σ(Z)^{2}-\bar{Z}$ relationship provides a numerical formalism to connect the self-enrichment and pre-enrichment between star clusters and dwarf galaxies using physically motivated chemical enrichment parameters.
description: Accepted for publication in AJ. 7 Figures, 2 Tables
Doctoral thesis recital (guitar (chamber))
Creators: name: Ilie, Dragos
Publisher: name: The University of Texas at Austin
Year: 2023
Subjects: Guitar music
Guitar music (Guitars (2))
Plucked instrument quartets (Guitars (4))
Songs (High voice) with guitar
Chamber music

description: Sonatina / Tansman -- Lyric quartet / Bogdanovic -- Siete canciones / Falla -- Samba volatil / Lyons -- Brandenburg concerto no.3 / Bach -- La vida breve / Falla
Strange Quark Contribution to the Nucleon Spin from Electroweak Elastic Scattering Data
Creators: name: Pate, S. F.
name: Schaub, J. P.
name: Trujillo, D. P.
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The total contribution of strange quarks to the intrinsic spin of the nucleon can be determined from a measurement of the strange-quark contribution to the nucleon's elastic axial form factor. We have studied the strangeness contribution to the elastic vector and axial form factors of the nucleon, using elastic electroweak scattering data. Specifically, we combine elastic $νp$ and $\barν p$ scattering cross section data from the Brookhaven E734 experiment with elastic $ep$ and quasi-elastic $ed$ and $e$-$^4$He scattering parity-violating asymmetry data from the SAMPLE, HAPPEx, G0 and PVA4 experiments. We have not only determined these form factors at individual values of momentum-transfer ($Q^2$), but also have fit the $Q^2$-dependence of these form factors using simple functional forms. We present the results of these fits, along with some expectations of how our knowledge of these form factors can be improved with data from Fermilab experiments.
description: 3 pages, 1 figure, CIPANP 2012
The Lense-Thirring effect on the Galilean moons of Jupiter
Creators: name: Iorio, Lorenzo
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: The perspectives of detecting the general relativistic gravitomagnetic Lense-Thirring effect on the orbits of the Galilean moons of Jupiter induced by the angular momentum ${\boldsymbol{S}}$ of the latter are preliminarily investigated. Numerical integrations over one century show that the expected gravitomagnetic signatures of the directly observable right ascension $α$ and declination $δ$ of the satellites are as large as tens of arcseconds for Io, while for Callisto they drop to the $\simeq 0.2\,\mathrm{arcseconds}$ level. Major competing effects due to the mismodeling in the zonal multipoles $J_\ell,\,\ell=2,\,3,\,4,\,\ldots$ of the Jovian non-spherically symmetric gravity field and in the Jupiter's spin axis ${\boldsymbol{\hat{k}}}$ should have a limited impact, especially in view of the future improvements in determining such parameters expected after the completion of the ongoing Juno mission in the next few years. On the other hand, the masses of the satellites, responsible of their mutual $N-$body perturbations, should be known better than now. Such a task should be accomplished with the future JUICE and Clipper missions to the Jovian system. Present-day accuracy in knowing the orbits of the Jovian Galilean satellites is of the order of 10 milliarcseconds, to be likely further improved thanks to the ongoing re-reduction of old photographic plates. This suggests that, in the next future, the Lense-Thirring effect in the main Jovian system of moons might be detectable with dedicated data reductions in which the gravitomagnetic field is explicitly modeled and solved-for.
description: LaTex2e, 20 pages, 4 figures, no tables. Refereed version accepted for publication in Universe
N=4 supersymmetry and the Belavin-Polyakov-Shvarts-Tyupkin instanton
Creators: name: Krivonos, Sergey
name: Lechtenfeld, Olaf
name: Sutulin, Anton
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2010
Subjects: subject: Hamiltonian formulations
subject: Lagrangian formulations
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: In this paper we construct the Lagrangian and Hamiltonian formulations of N=4 supersymmetric systems describing the motion of an isospin particle on a conformally flat four-manifold with SO(4) isometry carrying the non-Abelian field of a Belavin-Polyakov-Shvarts-Tyupkin instanton. The conformal factor can be specified to yield various particular systems, such as superconformally invariant mechanics as well as a particle on the four-sphere, the pseudosphere, or on R×S3. The isospin degrees of freedom arise as bosonic components of an additional fermionic N=4 supermultiplet, whose other components are rendered auxiliary by a nonlocal redefinition. Our on-shell component action coincides with the one recently proposed in [arXiv:0912.3289].
Single source unsplittable flows with arc-wise lower and upper bounds
Creators: name: Morell, Sarah
name: Skutella, Martin
Publisher: name: Technische Universität Berlin
Year: 2021
Subjects: subject: 510 Mathematik
subject: network flow
subject: unsplittable flow
subject: rounding
subject: flow augmentation

description: In a digraph with a source and several destination nodes with associated demands, an unsplittable flow routes each demand along a single path from the common source to its destination. Given some flow x that is not necessarily unsplittable but satisfies all demands, it is a natural question to ask for an unsplittable flow y that does not deviate from x by too much, i.e., ya≈xa for all arcs a. Twenty years ago, in a landmark paper, Dinitz et al. (Combinatorica 19:17–41, 1999) proved that there exists an unsplittable flow y such that ya≤xa+dmax for all arcs a, where dmax denotes the maximum demand value. Our first contribution is a considerably simpler one-page proof for this classical result, based upon an entirely new approach. Secondly, using a subtle variant of this approach, we obtain a new result: There is an unsplittable flow y such that ya≥xa−dmax for all arcs a. Finally, building upon an iterative rounding technique previously introduced by Kolliopoulos and Stein (SIAM J Comput 31:919–946, 2002) and Skutella (Math Program 91:493–514, 2002), we prove existence of an unsplittable flow that simultaneously satisfies the upper and lower bounds for the special case when demands are integer multiples of each other. For arbitrary demand values, we prove the weaker simultaneous bounds xa/2−dmax≤ya≤2xa+dmax for all arcs a.
Fabrication and characterization of the gapless half-Heusler YPtSb thin films
Creators: name: Wang, Wenhong
name: Du, Yin
name: Liu, Enke
name: Liu, Zhongyuan
name: Wu, Guangheng
Publisher: name: arXiv
Year: 2012
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Half-Heusler YPtSb thin films were fabricated by magnetron co-sputtering method on MgO-buffered SiO2/Si(001) substrates. X-ray diffraction pattern and Energy dispersive X-ray spectroscopy confirmed the high-quality growth and stoichiometry. The temperature dependence of the resistivity shows a semiconducting-type behavior down to low temperature. The Hall mobility was determined to be 450 cm2/Vs at 300K, which is much higher than the bulk value (300 cm2/Vs). In-plane magnetoresistance (MR) measurements with fields applied along and perpendicular to the current direction show opposite MR signs, which suggests the possible existence of the topological surface states.
description: 16 pages, 3 figures, 1 table, submitted for publication
Supersymmetric Calogero models by gauging
Creators: name: Fedoruk, Sergey
name: Ivanov, Evgeny
name: Lechtenfeld, Olaf
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2009
Subjects: subject: Calogero system
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: New superconformal extensions of d=1 Calogero-type systems are obtained by gauging the U(n) isometry of matrix superfield models. We consider the cases of N=1, N=2, and N=4 as one-dimensional supersymmetries. The bosonic core of the N=1 and N=2 models is the standard conformal An−1 Calogero system, whereas the N=4 model is an extension of the U(2)-spin Calogero system.
Chern-Simons flows on Aloff-Wallach spaces and spin(7) instantons
Creators: name: Haupt, Alexander S.
name: Ivanova, Tatiana A.
name: Lechtenfeld, Olaf
name: Popov, Alexander D.
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2011
Subjects: subject: Aloff-Wallach
subject: Bogomol’nyi-Prasad-Sommerfeld
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: Because of their explicit construction, Aloff-Wallach spaces are prominent in flux compactifications. They carry G2 structures and admit the G2-instanton equations, which are natural Bogomol’nyi-Prasad-Sommerfeld equations for Yang-Mills instantons on seven-manifolds and extremize a Chern-Simons–type functional. We consider the Chern-Simons flow between different G2 instantons on Aloff-Wallach spaces, which is equivalent to spin(7) instantons on a cylinder over them. For a general SU(3)-equivariant gauge connection, the generalized instanton equations turn into gradient-flow equations on C3×R2, with a particular cubic superpotential. For the simplest member of the Aloff-Wallach family (with 3-Sasakian structure) we present an explicit instanton solution of tanh-like shape.
The Effect of Boundary Conditions on Structure Formation in Fuzzy Dark Matter
Creators: name: Alvarez-Ríos, Iván
name: Guzmán, Francisco S.
name: Shapiro, Paul R.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We illustrate the effect of boundary conditions on the evolution of structure in Fuzzy Dark Matter. Scenarios explored include the evolution of single, ground-state equilibrium solutions of the Schrödinger-Poisson system, the relaxation of a Gaussian density fluctuation, mergers of two equilibrium configurations, and the random merger of many solitons. For comparison, each scenario is evolved twice, with isolation boundary conditions and periodic boundary conditions, the two commonly used to simulate isolated systems and structure formation, respectively. Replacing isolation boundary conditions by periodic boundary conditions changes the domain topology and dynamics of each scenario, by affecting the outcome of gravitational cooling. With periodic boundary conditions, the ground-state equilibrium solution and Gaussian fluctuation each evolve toward the single equilibrium solitonic core of the isolated case, but surrounded by a tail, unlike the isolated versions. The case of head-on, binary mergers illustrates additional effects, caused by the pull suffered by the system due to the infinite network of periodic images along each direction of the domain. Binary merger with angular momentum is the first scenario we found in which the tail has a polynomial profile when using a periodic domain. Finally, the 3D merger of many, randomly-placed solitonic cores of different mass makes a solitonic core surrounded by a tail with power-law-like density profile, for periodic boundary conditions, while producing a core with a much sharper fall-off in the isolated case. This suggests that the conclusion of earlier work that the ground-state equilibrium solution is an attractor for the asymptotic state is true even in 3D and for general circumstances, but only if gravitational cooling is able to carry mass and energy off to infinity, which isolation boundary conditions allow, but periodic ones do not.
description: 17 pages, 18 figures, modifications applied in order to match the accepted version in Phys. Rev. D
Longitudinal to transversal conversion of mode-locked states in an empty optical resonator
Creators: name: Zwilich, Michael
name: Schepers, Florian
name: Fallnich, Carsten
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: A longitudinal mode-locked state can be converted to a transverse mode-locked state by exploiting the spectral and spatial filtering of an empty optical resonator. Carrier and amplitude modulation sidebands were simultaneously transmitted by the conversion resonator, yielding phase-locked superpositions of up to five transverse modes. Equivalently, an amplitude-modulated beam was converted into a beam that periodically moved across the transverse plane. Precise control over the spatial beam shape during oscillation was gained by independently altering the set of transverse modes and their respective powers, which demonstrated an increased level of control in the generation of transverse mode-locked states.
description: 11 pages, 4 figures. Supplement: 5 pages, 5 figures
Spin-spin correlations between two Kondo impurities coupled to an open Hubbard chain
Creators: name: Tiegel, A.C.
name: Dargel, P.E.
name: Hallberg, K.A.
name: Frahm, Holger
name: Pruschke, T.
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2013
Subjects: subject: Ruderman-Kittel-Kasuya-Yosida
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: In order to study the interplay between Kondo and Ruderman-Kittel-Kasuya-Yosida interaction, we calculate the spin-spin correlation functions between two Kondo impurities coupled to different sites of a half-filled open Hubbard chain. Using the density-matrix renormalization group (DMRG), we reexamine the exponents for the power-law decay of the correlation function between the two impurity spins as a function of the antiferromagnetic coupling J, the Hubbard interaction U, and the distance R between the impurities. The exponents for finite systems obtained in this work deviate from previously published DMRG calculations. We furthermore show that the long-distance behavior of the exponents is the same for impurities coupled to the bulk or to both ends of the chain. We note that a universal exponent for the asymptotic behavior can not be extracted from these finite-size systems with open boundary conditions.
Quantum phases of a chain of strongly interacting anyons
Creators: name: Finch, Peter E.
name: Frahm, Holger
name: Lewerenz, Marius
name: Milsted, Ashley
name: Osborne, Tobias J.
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2014
Subjects: subject: non-Abelian anyonic quasiparticles
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: Quantum gates for the manipulation of topological qubits rely on interactions between non-Abelian anyonic quasiparticles. We study the collective behavior of systems of anyons arising from such interactions. In particular, we study the effect of favoring different fusion channels of the screened Majorana spins appearing in the recently proposed topological Kondo effect. Based on the numerical solution of a chain of SO(5)2 anyons we identify two critical phases whose low-energy behavior is characterized by conformal field theories with central charges c=1 and c=8/7, respectively. Our results are complemented by exact results for special values of the coupling constants which provide additional information about the corresponding phase transitions.
Superintegrability of generalized Calogero models with oscillator or Coulomb potential
Creators: name: Hakobyan, Tigran
name: Lechtenfeld, Olaf
name: Nersessian, Armen
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2014
Subjects: subject: Coulomb systems
subject: Runge–Lenz vector
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: We deform N-dimensional (Euclidean, spherical and hyperbolic) oscillator and Coulomb systems, replacing their angular degrees of freedom by those of a generalized rational Calogero model. Using the action-angle description, it is established that maximal superintegrability is retained. For the rational Calogero model with Coulomb potential, we present all constants of motion via matrix model reduction. In particular, we construct the analog of the Runge–Lenz vector.
Gauge-Invariant Measure of the Magnon Orbital Angular Momentum
Creators: name: Fishman, Randy S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Unlike the Berry phase, the orbital angular momentum (OAM) of magnons with two-dimensional wavevector k in band n is not gauge invariant for arbitrary phase lambda_n(k). However, by integrating the OAM over the orientation $ϕ$ of wavevector k, we construct a gauge-invariant function F_n(k). Like F_n(k), the average OAM for magnon band n in a circle of radius k is also gauge invariant. We demonstrate these results for a ferromagnet on a honeycomb lattice with Dzyalloshinskii-Moriya interactions between next-nearest neighbor spins. With wavevectors k restricted to the first Brillouin zone, the angular averaged OAM F_n(k) then has opposite signs for lower and upper bands n=1 and 2 for all k.
description: 6 figures
Higher-derivative N=4 superparticle in three-dimensional spacetime
Creators: name: Kozyrev, Nikolay
name: Krivonos, Sergey
name: Lechtenfeld, Olaf
name: Nersessian, Armen
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2014
Subjects: subject: supersymmetric anyon
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: Using the coset approach (nonlinear realization) we construct component actions for a superparticle in three-dimensional spacetime with N=4 supersymmetry partially broken to N=2. These actions may contain an anyonic term and the square of the first extrinsic worldline curvature. We present the supercharges for the unbroken and broken supersymmetries as well as the Hamiltonian for the supersymmetric anyon. In terms of the nonlinear realization superfields, the superspace actions take a simple form in all cases.
Ostraciidae
Creators: name: Fricke, Ronald
name: Allen, Gerald R.
name: Andréfouët, Serge
name: Chen, Wei-Jen
name: Hamel, Mélanie A.
name: Laboute, Pierre
name: Mana, Ralph
name: Hui, Tan Heok
name: Uyeno, Daisuke
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Tetraodontiformes
Ostraciidae

description: Ostraciidae    Ostracion cubicus Linnaeus, 1758  —Yellow boxfish
 STATUS AT MADANG. New record from Madang, based on specimens oberved by G. R. Allen. DISTRIBUTION AND HABITAT. Red Sea, East and South Africa, Madagascar and Mascarenes east to Tuamotu Archipelago, north to Ryukyu and Ogasawara islands, south to northern New Zealand, Lord Howe and Rapa islands, straying to Hawaiian Islands. Found in lagoon and semi-sheltered seaward reefs; juveniles often among Acropora corals, 0– 280 m. Marine.
  Ostracion meleagris Shaw in Shaw & Nodder, 1796  —Spotted boxfish
 STATUS AT MADANG. New record from Madang, based on specimens observed and photographed at St. CTR 0 4, CTR 12, CTR 14, CTR 15, CTR 20. CAS material (CAS 65651, 65652)
DISTRIBUTION AND HABITAT. East and South Africa, Madagascar and Mascarenes east to Mexico, north to southern Japan, Ogasawara and Hawaiian islands, south to Great Barrier Reef (Australia), Lord Howe Island, New Caledonia and Rapa. Found in clear lagoon and seaward reefs; juveniles among rocky boulders, adults on reef crests and slopes, 0– 58 m. Marine.
  Ostracion solorensis Bleeker, 1853  —Solor boxfish
STATUS AT MADANG. First record from Madang by Allen & Erdmann (2012: 1084). Specimens photographed at St. CTR 22, PR 105, and by A. Berberian. AMS material.
DISTRIBUTION AND HABITAT. Indonesia east to Palau, Fiji and Tonga, north to Philippines, south to northern Australia and New Caledonia. Found in seaward coral reefs, 1– 20 m. Marine.
description: Published as part of Fricke, Ronald, Allen, Gerald R., Andréfouët, Serge, Chen, Wei-Jen, Hamel, Mélanie A., Laboute, Pierre, Mana, Ralph, Hui, Tan Heok & Uyeno, Daisuke, 2014, Checklist of the marine and estuarine fishes of Madang District, Papua New Guinea, western Pacific Ocean, with 820 new records, pp. 1-247 in Zootaxa 3832 (1) on page 197, DOI: 10.11646/zootaxa.3832.1.1, http://zenodo.org/record/250559
Magnetic ordering and structural phase transitions in strained ultrathin SrRuO$_{3}$/SrTiO$_{3}$ superlattice
Creators: name: Gu, Mingqiang
name: Xie, Qiyun
name: Shen, Xuan
name: Xie, Rubin
name: Wang, Jianli
name: Tang, Gang
name: Wu, Di
name: Zhang, G. P.
name: Wu, X. S.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Ruthenium-based perovskite systems are attractive because their Structural, electronic and magnetic properties can be systematically engineered. SrRuO$_3$/SrTiO$_3$ superlattice, with its period consisting of one unit cell each, is very sensitive to strain change. Our first-principles simulations reveal that in the high tensile strain region, it transits from a ferromagnetic (FM) metal to an antiferromagnetic (AFM) insulator with clear tilted octahedra, while in the low strain region, it is a ferromagnetic metal without octahedra tilting. Detailed analyses of three spin-down Ru-t$_{2g}$ orbitals just below the Fermi level reveal that the splitting of these orbitals underlies these dramatic phase transitions, with the rotational force constant of RuO$_6$ octahedron high up to 16 meV/Deg$^2$, 4 times larger than that of TiO$_6$. Differently from nearly all the previous studies, these transitions can be probed optically through the diagonal and off-diagonal dielectric tensor elements. For one percent change in strain, our experimental spin moment change is -0.14$\pm$0.06 $μ_B$, quantitatively consistent with our theoretical value of -0.1 $μ_B$.
description: 3 figures, 1 supplementary material, accepted by Phys. Rev. Lett
Resonant plasmonic detection of terahertz radiation in field-effect transistors with the graphene channel and the black-As$_x$P$_{1-x}$ gate layer
Creators: name: Ryzhii, V.
name: Tang, C.
name: Otsuji, T.
name: Ryzhii, M.
name: Mitin, V.
name: Shur, M. S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We propose the terahertz (THz) detectors based on field-effect transistors (FETs) with the graphene channel (GC) and the black-Arsenic (b-As) black-Phosphorus (b-P), or black-Arsenic-Phosphorus (b-As$_x$P$_{1-x}$) gate barrier layer. The operation of the GC-FET detectors is associated with the carrier heating in the GC by the THz electric field resonantly excited by incoming radiation leading to an increase in the rectified current between the channel and the gate over the b-As$_x$P$_{1-x}$ energy barrier layer (BLs). The specific feature of the GC-FETs under consideration is relatively low energy BLs and the possibility to optimize the device characteristics by choosing the barriers containing a necessary number of the b-As$_x$P$_{1-x}$ atomic layers and a proper gate voltage. The excitation of the plasma oscillations in the GC-FETs leads to the resonant reinforcement of the carrier heating and the enhancement of the detector responsivity. The room temperature responsivity can exceed the values of $10^3$~A/W. The speed of the GC-FET detector's response to the modulated THz radiation is determined by the processes of carrier heating. As shown, the modulation frequency can be in the range of several GHz at room temperatures.
description: 13 pages, 5 figures
Exact solution of the D3 non-Abelian anyon chain
Creators: name: Braylovskaya, Natalia
name: Finch, Peter E.
name: Frahm, Holger
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2016
Subjects: subject: XXZ Heisenberg spin chain
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: Commuting transfer matrices for linear chains of interacting non-Abelian anyons from the two-dimensional irreducible representation of the dihedral group D3 [or, equivalently, the integer sector of the su(2)4 spin-1 chain] are constructed using the spin-anyon correspondence to a D3-symmetric formulation of the XXZ Heisenberg spin chain. The spectral problem is solved using discrete inversion identities satisfied by these transfer matrices and functional Bethe ansatz methods. The resulting spectrum can be related to that of the XXZ spin-1/2 Heisenberg chain with boundary conditions depending on the topological sector of the anyon chain. The properties of this model in the critical regime are studied by finite size analysis of the spectrum. In particular, points in the phase diagram where the anyon chain realizes some of the rational Z2 orbifold theories are identified.
Lieutenant Chevalier: Souvenirs des guerres napoléoniennes, publiés d’après le manuscrit original par Jean Mistler, de l’Académie française, et Héléne Michaud, conservateur de la Bibliothèque Thiers, 1970
Creators: name: Hammer, Karl
Publisher: name: Francia
Year: 2019

description: -
description: Francia, Bd. 2 (1974)
Spherical Calogero model with oscillator/Coulomb potential: Classical case
Creators: name: Correa, Francisco
name: Hakobyan, Tigran
name: Lechtenfeld, Olaf
name: Nersessian, Armen
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2016
Subjects: subject: Quantum theory
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: We construct the Hamiltonians and symmetry generators of Calogero-oscillator and Calogero-Coulomb models on the N-dimensional sphere within the matrix-model reduction approach. Our method also produces the integrable Calogero-Coulomb-Stark model on the sphere and proves the integrability of the spin extensions of all these systems.
Extraction of volumetric indices from echocardiography: which deep learning solution for clinical use?
Creators: name: Ling, Hang Jung
name: Painchaud, Nathan
name: Courand, Pierre-Yves
name: Jodoin, Pierre-Marc
name: Garcia, Damien
name: Bernard, Olivier
Publisher: name: arXiv
Year: 2023
Subjects: subject: Image and Video Processing (eess.IV)
subject: Artificial Intelligence (cs.AI)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Deep learning-based methods have spearheaded the automatic analysis of echocardiographic images, taking advantage of the publication of multiple open access datasets annotated by experts (CAMUS being one of the largest public databases). However, these models are still considered unreliable by clinicians due to unresolved issues concerning i) the temporal consistency of their predictions, and ii) their ability to generalize across datasets. In this context, we propose a comprehensive comparison between the current best performing methods in medical/echocardiographic image segmentation, with a particular focus on temporal consistency and cross-dataset aspects. We introduce a new private dataset, named CARDINAL, of apical two-chamber and apical four-chamber sequences, with reference segmentation over the full cardiac cycle. We show that the proposed 3D nnU-Net outperforms alternative 2D and recurrent segmentation methods. We also report that the best models trained on CARDINAL, when tested on CAMUS without any fine-tuning, still manage to perform competitively with respect to prior methods. Overall, the experimental results suggest that with sufficient training data, 3D nnU-Net could become the first automated tool to finally meet the standards of an everyday clinical device.
description: 10 pages, accepted for FIMH 2023; camera ready corrections, corrected acknowledgments
Higher-derivative superparticle in AdS3 space
Creators: name: Kozyrev, Nikolay
name: Krivonos, Sergey
name: Lechtenfeld, Olaf
Publisher: name: College Park (Maryland) : American Physical Society
Year: 2016
Subjects: subject: quantum field theory
subject: superparticle moving
subject: covariant Cartan forms
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: Employing the coset approach we construct component actions for a superparticle moving in AdS3 with N=(2,0), D=3 supersymmetry partially broken to N=2, d=1. These actions may contain higher time-derivative terms, which are chosen to possess the same (super)symmetries as the free superparticle. In terms of the nonlinear-realization superfields, the component actions always take a simpler form when written in terms of covariant Cartan forms. We also consider in detail the reduction to the nonrelativistic case and construct the corresponding action of a Newton-Hooke superparticle and its higher-derivative generalizations. The structure of these higher time-derivative generalizations is completely fixed by invariance under the supersymmetric Newton-Hooke algebra extended by two central charges.
title: Relativistic Mean-Field Models with Different Parametrizations of Density Dependent Couplings
Creators: name: Typel, Stefan
Publisher: name: MDPI
Year: 2023

description: Relativistic mean-field models are successfully used for the description of finite nuclei and nuclear matter. Approaches with density-dependent meson-nucleon couplings assume specific functional forms and a dependence on vector densities in most cases. In this work, parametrizations with a larger sample of functions and dependencies on vector and scalar densities are investigated. They are obtained from fitting properties of finite nuclei. The quality of the description of nuclei and the obtained equations of state of symmetric nuclear matter and neutron matter below saturation are very similar. However, characteristic nuclear matter parameters, the equations of state and the symmetry energy at suprasaturation densities show some correlations with the choice of the density dependence and functional form of the couplings. Conditions are identified that can lead to problems for some of the parametrizations.
Maximal violation of Bell inequalities by position measurements
Creators: name: Kiukas, J.
name: Werner, R.F.
Publisher: name: College Park, MD : American Institute of Physics
Year: 2010
Subjects: subject: Clauser-Horne-Shimony-Holt
subject: quantum particles
subject: Bell violations
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: We show that it is possible to find maximal violations of the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality using only position measurements on a pair of entangled nonrelativistic free particles. The device settings required in the CHSH inequality are done by choosing one of two times at which position is measured. For different assignments of the “+” outcome to positions, namely, to an interval, to a half-line, or to a periodic set, we determine violations of the inequalities and states where they are attained. These results have consequences for the hidden variable theories of Bohm and Nelson, in which the two-time correlations between distant particle trajectories have a joint distribution, and hence cannot violate any Bell inequality.
The Herschel Virgo Cluster Survey XII: FIR properties of optically-selected Virgo Cluster galaxies
Creators: name: Auld, R.
name: Bianchi, S.
name: Smith, M. W. L.
name: Davies, J. I.
name: Bendo, G. J.
name: Alighieri, S. di Serego
name: Cortese, L.
name: Baes, M.
name: Bomans, D. J.
name: Boquien, M.
name: Boselli, A.
name: Ciesla, L.
name: Clemens, M.
name: Corbelli, E.
name: De Looze, I.
name: Fritz, J.
name: Gavazzi, G.
name: Pappalardo, C.
name: Grossi, M.
name: Hunt, L. K.
name: Madden, S.
name: Magrini, L.
name: Pohlen, M.
name: Verstappen, J.
name: Vlahakis, C.
name: Xilouris, E. M.
name: Zibetti, S.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The Herschel Virgo Cluster Survey (HeViCS) is the deepest, confusion-limited survey of the Virgo Cluster at far-infrared (FIR) wavelengths. The entire survey at full depth covers $\sim$55 sq. deg. in 5 bands (100-500 \micron), encompassing the areas around the central dominant elliptical galaxies (M87, M86 & M49) and extends as far as the NW cloud, the W cloud and the Southern extension. The survey extends beyond this region with lower sensitivity so that the total area covered is 84 sq. deg. In this paper we describe the data, the data acquisition techniques and present the detection rates of the optically selected Virgo Cluster Catalogue (VCC). We detect 254 (34%) of 750 VCC galaxies found within the survey boundary in at least one band and 171 galaxies are detected in all five bands. For the remainder of the galaxies we have measured strict upper limits for their FIR emission. The population of detected galaxies contains early- as well as late-types although the latter dominate the detection statistics. We have modelled 168 galaxies, showing no evidence of a strong synchrotron component in their FIR spectra, using a single-temperature modified blackbody spectrum with a fixed emissivity index ($β= 2$). A study of the $χ^2$ distribution indicates that this model is not appropriate in all cases, and this is supported by the FIR colours which indicate a spread in $β$=1--2. Statistical comparison of the dust mass and temperature distributions from 140 galaxies with $χ^2_{dof=3} < 7.8$ (95% confidence level) shows that late-types have typically colder, more massive dust reservoirs; the early-type dust masses have a mean of ${\rm log}( / M_{\sun}) = 6.3 \pm 0.3 $, while for late-types ${\rm log}( / M_{\sun}) =7.1 \pm 0.1$... (abridged)
description: 47 pages, 14 figures, 6 tables, accepted for publication in MNRAS
Time asymptotics and entanglement generation of Clifford quantum cellular automata
Creators: name: Gütschow, Johannes
name: Uphoff, Sonja
name: Werner, Reinhard F.
name: Zimborás, Zoltán
Publisher: name: College Park, MD : American Institute of Physics
Year: 2010
Subjects: subject: Quantum cellular automata
subject: Lieb–Robinson bounds
subject: translation-invariant states
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: We consider Clifford quantum cellular automata (CQCAs) and their time-evolution. CQCAs are an especially simple type of quantum cellular automata, yet they show complex asymptotics and can even be a basic ingredient for universal quantum computation. In this work we study the time evolution of different classes of CQCAs. We distinguish between periodic CQCAs, fractal CQCAs, and CQCAs with gliders. We then identify invariant states and study convergence properties of classes of states, such as quasifree and stabilizer states. Finally, we consider the generation of entanglement analytically and numerically for stabilizer and quasifree states
title: Computing with noise in spiking neural networks
Creators: name: Bytschok, Ilja
Publisher: name: Heidelberg University Library
Year: 2017

description: Trial-to-trial variability is an ubiquitous characteristic in neural firing patterns and is
often regarded as a side-effect of intrinsic noise. Increasing evidence indicates that this
variability is a signature of network computation. The computational role of noise is not
yet clear and existing frameworks use abstract models for stochastic computation. In
this work, we use networks of spiking neurons to perform stochastic inference by sam-
pling. We provide a novel analytical description of the neural response function with an
unprecedented range of validity. This description enables an implementation of spiking
networks in simulations to sample from Boltzmann distributions. We show the robust-
ness of these networks to parameter variations and highlight the substantial advantages
of short-term plasticity in our framework. We demonstrate accelerated inference on neu-
romorphic hardware with a speed-up of 10^4 compared to biological networks, regardless
of network size. We further explore the role of noise as a computational component in
our sampling networks and identify the functional equivalence between synaptic connec-
tions and mutually shared noise. Based on this, we implement interconnected sampling
ensembles which exploit their activity as noise resource to maintain a stochastic firing
regime.