cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Long-time stability of breathers in Hamiltonian $\cal PT$-symmetric lattices
Creators: name: Chernyavsky, Alexander
name: Pelinovsky, Dmitry E.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mathematical Physics (math-ph)
subject: Dynamical Systems (math.DS)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We consider the Hamiltonian version of a $\cal PT$-symmetric lattice that describes dynamics of coupled pendula under a resonant periodic force. Using the asymptotic limit of a weak coupling between the pendula, we prove the nonlinear long-time stability of breathers (time-periodic solutions localized in the lattice) by using the Lyapunov method. Breathers are saddle points of the extended energy function, which are located between the continuous bands of positive and negative energy. Nevertheless, we construct an approximate Lyapunov function and estimate its evolution on a long but finite time interval. The nonlinear stability analysis becomes possible for the $\cal PT$-symmetric lattice only because of the existence of a Hamiltonian structure.
Electronic Suppmentary Materials 1 from Male reproductive success is not strongly affected by phenological changes in mate availability in monoecious Sagittaria latifolia
Creators: name: Kwok, Allison
name: Stephens, Samantha
name: Dorken, Marcel
Publisher: name: The Royal Society
Year: 2023
Subjects: subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: Ecology
subject: Plant Biology

description: Alternative GLME/LME models and figures of full flowering season.
A re-investigation of debris disc halos
Creators: name: Thebault, Philippe
name: Olofsson, Johan
name: Kral, Quentin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: A significant fraction of debris discs consist of a bright ring beyond which extends a wide halo. Such a halo should be made of small grains produced in the ring of parent bodies (PB) and pushed on high-e orbits by radiation pressure. It has been shown that, under several simplifying assumptions, the surface brightness (SB) of this halo should radially decrease as $r^{-3.5}$ in scattered light. We aim to revisit the halo phenomenon and focus on two so far unexplored issues: 1) How the unavoidable presence of small unbound grains, non-isotropic scattering phase functions (SPF) and finite instrument resolution affect scattered light SB profiles, and 2) How the halo phenomenon manifests itself at longer wavelengths. We find that unbound grains account for a significant fraction of the halo's luminosity in scattered light, and can significantly flatten the SB radial profile. Realistic size-dependent SPFs also have an effect, resulting here again in shallower SB profiles. For edge-on discs, non-resolving the vertical profile can also flatten the projected SB. We show that roughly half of the observationally-derived halo profiles found in the literature are compatible with our new results, and that roughly half of the remaining systems are probably shaped by additional processes. We also propose that, in future observational studies, the characteristics of PB belt and halos should be fitted separately. In thermal emission, wide halos should remain detectable up to the far-IR and, with the exception of the $\sim 8-15μ$m domain, the halo accounts for more than half of the system's total flux up to $λ\sim80-90μ$m. The halo's contribution strongly decreases in the sub-mm to mm but still represents a few percents of the system's luminosity at $λ\sim 1$mm. For unresolved systems, the presence of a halo can also affect the determination of the disc's radius from its SED.
description: accepted for publication in A&A (abstract significantly shortened to comply with arxiv limits)
Dual symmetry in a generalized Maxwell theory
Creators: name: Brandt, F. T.
name: Frenkel, J.
name: McKeon, D. G. C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We examine Podolsky's electrodynamics, which is noninvariant under the usual duality transformation. We deduce a generalization of Hodge's star duality, which leads to a dual gauge field and restores to a certain extent the dual symmetry. The model becomes fully dual symmetric asymptotically when it reduces to the Maxwell theory. We argue that this strict dual symmetry directly implies the existence of the basic invariants of the electromagnetic fields.
description: Four pages. Accepted for publication in Modern Physics Letters A
Small-angle scattering studies of intrinsically disordered proteins and their complexes
Creators: name: Cordeiro, Tiago
name: Herranz-Trillo, Fatima
name: Urbanek, Annika
name: Estaña, Alejandro
name: Cortés, Juan
name: Sibille, Nathalie
name: Bernadó, Pau
Publisher: name: arXiv
Year: 2016
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Biomolecules (q-bio.BM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Intrinsically Disordered Proteins (IDPs) perform a broad range of biological functions. Their relevance has motivated intense research activity seeking to characterize their sequence/structure/function relationships. However, the conformational plasticity of these molecules hampers the application of traditional structural approaches, and new tools and concepts are being developed to address the challenges they pose. Small-Angle Scattering (SAS) is a structural biology technique that probes the size and shape of disordered proteins and their complexes with other biomolecules. The low-resolution nature of SAS can be compensated with specially designed computational tools and its combined interpretation with complementary structural information. In this review, we describe recent advances in the application of SAS to disordered proteins and highly flexible complexes and discuss current challenges.
Multi-phase induced inflation in theories with non-minimal coupling to gravity
Creators: name: Artymowski, Michal
name: Lalak, Zygmunt
name: Lewicki, Marek
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we investigate the induced inflation with two flat regions: one Starobinsky-like plateau in big field regime and one shorter plateau around the saddle point of the Einstein frame potential. This multi-phase inflationary scenario can be used to solve the problem of classical cosmology. The inflation at the saddle-point plateau is consistent with the data and can have arbitrarily low scale. The results can be useful in the context of the Higgs-Axion relaxation and in a certain limit they are equivalent to the $α$-attractors.
description: 13 pages, 5 figures
Close encounters of the sticky kind: Brownian motion at absorbing boundaries
Creators: name: Bressloff, Paul C
Publisher: name: arXiv
Year: 2023
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Probability (math.PR)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: Encounter-based models of diffusion provide a probabilistic framework for analyzing the effects of a partially absorbing reactive surface, in which the probability of absorption depends upon the amount of surface-particle contact time. Prior to absorption, the surface is typically assumed to act as a totally reflecting boundary, which means that the contact time is determined by a Brownian functional known as the boundary local time. In this paper we develop a class of encounter-based models that deal with absorption at sticky boundaries. Sticky boundaries occur in a diverse range of applications, including cell biology, colloidal physics, active matter, finance, and human crowd dynamics. We begin by constructing a one-dimensional encounter-based model of sticky Brownian motion (BM), which is based on the zero-range limit of non-sticky BM with a short-range attractive potential well near the origin. In this limit, the boundary-contact time is given by the amount of time (occupation time) that the particle spends at the origin. We calculate the joint probability density or propagator for the particle position and the occupation time, and then identify an absorption event as the first time that the occupation time crosses a randomly generated threshold. Different models of absorption correspond to different choices for the random threshold probability distribution. We illustrate the theory by considering diffusion in a finite interval with a partially absorbing sticky boundary at one end. We show how various quantities of interest depend on moments of the random threshold distribution. Finally, we determine how sticky BM can be obtained by taking a particular diffusion limit of a sticky run-and-tumble particle (RTP). The diffusion limit is well-defined provided that the velocity of the RTP is biased and spatially varying within a boundary layer around the origin.
description: 20 pages, 9 figures
An IllustrisTNG View of the Caustic Technique for Galaxy Cluster Mass Estimation
Creators: name: Pizzardo, Michele
name: Geller, Margaret J.
name: Kenyon, Scott J.
name: Damjanov, Ivana
name: Diaferio, Antonaldo
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The TNG300-1 run of the IllustrisTNG simulations includes 1697 clusters of galaxies with $M_{200c}>10^{14}$M$_\odot$ covering the redshift range $0.01-1.04$. We build mock spectroscopic redshift catalogues of simulated galaxies within these clusters and apply the caustic technique to estimate the cumulative cluster mass profiles. We compute the total true cumulative mass profile from the 3D simulation data and calculate the ratio of caustic mass to total 3D mass, $\mathcal{F}_β$, as a function of cluster-centric distance and identify the radial range where $\mathcal{F}_β$ is roughly constant. The filling factor, $\mathcal{F}_β=0.41\pm 0.08$, is constant on a plateau that covers a wide cluster-centric distance range, $(0.6-4.2)R_{200c}$. This calibration is insensitive to redshift. The calibrated caustic mass profiles are unbiased, with an average uncertainty of $23\%$. At $R_{200c}$, the average $M^C/M^{3D}=1.03\pm 0.22$; at $2R_{200c}$, the average $M^C/M^{3D}=1.02\pm 0.23$. Simulated galaxies are unbiased tracers of the mass distribution. IllustrisTNG is a broad statistical platform for application of the caustic technique to large samples of clusters with spectroscopic redshifts for $\gtrsim 200$ members in each system. These observations will allow extensive comparisons with weak lensing masses and will complement other techniques for measuring the growth rate of structure in the universe.
description: 11 pages, 9 figures, 2 tables
The dusty circumstellar environment of Betelgeuse during the Great Dimming as seen by VLTI/MATISSE
Creators: name: Cannon, E.
name: Montargès, M.
name: de Koter, A.
name: Matter, A.
name: Sanchez-Bermudez, J.
name: Norris, R.
name: Paladini, C.
name: Decin, L.
name: Sana, H.
name: Sundqvist, J. O.
name: Lagadec, E.
name: Kervella, P.
name: Chiavassa, A.
name: Dupree, A. K.
name: Perrin, G.
name: Scicluna, P.
name: Stee, P.
name: Kraus, S.
name: Danchi, W.
name: Lopez, B.
name: Millour, F.
name: Drevon, J.
name: Cruzalèbes, P.
name: Berio, P.
name: Robbe-Dubois, S.
name: Rosales-Guzman, A.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The 'Great Dimming' of the prototypical red supergiant Betelgeuse, which occurred between December 2019 and April 2020, gives us unprecedented insight into the processes occurring on the stellar surface and in the inner wind of this type of star. In particular it may bring further understanding of their dust nucleation and mass loss processes. Here, we present and analyse VLTI/MATISSE observations in the N-band (8 - 13 $μ$m) taken near the brightness minimum in order to assess the status of the dusty circumstellar environment. We explore the compatibility of a dust clump obscuring the star with our mid-infrared interferometric observations using continuum 3D radiative transfer modelling, and probe the effect of adding multiple clumps close to the star on the observables. We also test the viability of a large cool spot on the stellar surface without dust present in the ambient medium. Using the visibility data, we derive a uniform disk diameter of 59.02 $\pm$ 0.64 mas in the spectral range 8 to 8.75 $μ$m. We find that both the dust clump and the cool spot models are compatible with the data. Further to this, we note that the extinction and emission of our localised dust clump in the line of sight of the star, directly compensate each other making the clump undetectable in the spectral energy distribution and visibilities. The lack of infrared brightening during the 'Great Dimming' therefore does not exclude extinction due to a dust clump as one of the possible mechanisms. The visibilities can be reproduced by a spherical wind with dust condensing at 13 stellar radii and a dust mass-loss rate of (2.1 - 4.9) $\times$ 10$^{-10}$ $\mathit{M}_{\odot} {\rm yr}^{-1}$, however, in order to reproduce the complexity of the observed closure phases, additional surface features or dust clumps would be needed.
description: 13 Pages, accepted for publication in A&A
The Search for Signatures Of Transient Mass Loss in Active Stars
Creators: name: Crosley, M. K.
name: Osten, R. A.
name: Broderick, J. W.
name: Corbel, S.
name: Eisloffel, J.
name: Griessmeier, J. -M.
name: Leeuwen, J.
name: Rowlinson, A.
name: Zarka, P.
name: Norman, C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The habitability of an exoplanet depends on many factors. One such factor is the impact of stellar eruptive events on nearby exoplanets. Currently this is poorly constrained due to heavy reliance on solar scaling relationships and a lack of experimental evidence. Potential impacts of Coronal Mass Ejections (CMEs), which are a large eruption of magnetic field and plasma from a star, are space weather and atmospheric stripping. A method for observing CMEs as they travel though the stellar atmosphere is the type II radio burst, and the new LOw Frequency ARray (LOFAR) provides a means for detection. We report on 15 hours of observation of YZ Canis Minoris (YZ CMi), a nearby M dwarf flare star, taken in LOFAR's beam-formed observation mode for the purposes of measuring transient frequency-dependent low frequency radio emission. The observations utilized Low-Band Antenna (10-90 MHz) or High-Band Antenna (110-190 MHz) for five three-hour observation periods. In this data set, there were no confirmed type II events in this frequency range. We explore the range of parameter space for type II bursts constrained by our observations Assuming the rate of shocks is a lower limit to the rate at which CMEs occur, no detections in a total of 15 hours of observation places a limit of $ν_{type II} < 0.0667$ shocks/hr $ \leq ν_{CME}$ for YZ CMi due to the stochastic nature of the events and limits of observational sensitivity. We propose a methodology to interpret jointly observed flares and CMEs which will provide greater constraints to CMEs and test the applicability of solar scaling relations.
Third order corrections to the ground state energy of the gas of spin $s$ fermions with arbitrary densities of different spin projections
Creators: name: Chankowski, Piotr H.
name: Wojtkiewicz, Jacek
name: Augustynowicz, Szymon
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Recently we have computed the third order corrections to the ground state energy of the arbitrarily polarized diluted gas of spin 1/2 fermions interacting through a spin-independent repulsive two-body potential. Here we extend this result to the gas of spin $s$ fermions - a system the Hamiltonian of which has an accidental $SU(2s+1)$ symmetry - with arbitrary densities of fermions having different spin projections. The corrections are computed semi-analytically using the effective field theory approach and are parametrized by the $s$- and $p$- wave scattering lengths $a_0$ and $a_1$ and the $s$-wave effective radius $r_0$, measurable in the low energy fermion-fermion elastic scattering. The result is used to study the impact the higher order corrections can have on the characteristics of the phase transition (at zero temperature) to the ordered phase (on the emergence of the itinerant ferromagnetism).
description: 21 pages, 5 figures
The behaviour of magnetoacoustic waves in the neighbourhood of a two-dimensional null point: initially cylindrically-symmetric perturbations
Creators: name: McLaughlin, J. A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The propagation of magnetoacoustic waves in the neighbourhood of a 2D null point is investigated for both $β=0$ and $β\neq 0$ plasmas. Previous work has shown that the Alfvén speed, here $v_A \propto r$, plays a vital role in such systems and so a natural choice is to switch to polar coordinates. For the $β=0$ plasma, we derive an analytical solution for the behaviour of the fast magnetoacoustic wave in terms of the Klein-Gordon equation. We also solve the system with a semi-analytical WKB approximation which shows that the $β=0$ wave focuses on the null and contracts around it but, due to exponential decay, never reaches the null in a finite time. For the $β\neq 0$ plasma, we solve the system numerically and find the behaviour to be similar to that of the $β=0$ system at large radii, but completely different close to the null. We show that for an initially cylindrically-symmetric fast magnetoacoustic wave perturbation, there is a decrease in wave speed along the separatrices and so the perturbation starts to take on a quasi-diamond shape; with the corners located along the separatrices. This is due to the growth in pressure gradients that reach a maximum along the separatrices, which in turn reduces the acceleration of the fast wave along the separatrices leading to a deformation of the wave morphology.
description: 27 pages, 10 figures
Quasi-periodic eruptions from impacts between the secondary and a rigidly precessing accretion disc in an extreme mass-ratio inspiral system
Creators: name: Franchini, Alessia
name: Bonetti, Matteo
name: Lupi, Alessandro
name: Miniutti, Giovanni
name: Bortolas, Elisa
name: Giustini, Margherita
name: Dotti, Massimo
name: Sesana, Alberto
name: Arcodia, Riccardo
name: Ryu, Taeho
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: X-ray quasi-periodic eruptions (QPEs) represent a recently discovered example of extreme X-ray variability associated with supermassive black holes. These are high-amplitude bursts recurring every few hours that are detected in the soft X-ray band from the nuclei of nearby galaxies whose optical spectra lack the broad emission lines typically observed in unobscured active galaxies. The physical origin of this new X-ray variability phenomenon is still unknown and several theoretical models have been presented. However, no attempt has been made so far to account for the varying QPE recurrence time and luminosity in individual sources, nor for the diversity of the QPE phenomenology in the different known erupters. We present a semi-analytical model based on an extreme mass-ratio inspiral (EMRI) system where the secondary intersects, along its orbit, a rigidly precessing accretion disc surrounding the primary. We assume that QPEs result from emission from an adiabatically expanding, initially optically thick gas cloud expelled from the disc plane at each impact. We produced synthetic X-ray light curves, which we then compared with X-ray data from four QPE sources: GSN 069, eRO-QPE1, eRO-QPE2, and RX J1301.9+2747. Our model aptly reproduces the diversity of QPE properties between the considered objects and it is also able to naturally account for the varying QPE amplitudes and recurrence times in individual sources. Future implementations will enable us to refine the match with the data and to estimate the system parameters precisely, making additional use of multi-epoch QPE data. We briefly discuss the nature of the secondary object, as well as the possible implications of our findings for the EMRI population at large.
description: 11 pages, 7 figures, accepted for publication in A&A
Kinetics of Aggregation with Choice
Creators: name: Ben-Naim, E.
name: Krapivsky, P. L.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We generalize the ordinary aggregation process to allow for choice. In ordinary aggregation, two random clusters merge and form a larger aggregate. In our implementation of choice, a target cluster and two candidate clusters are randomly selected, and the target cluster merges with the larger of the two candidate clusters. We study the long-time asymptotic behavior, and find that as in ordinary aggregation, the size density adheres to the standard scaling form. However, aggregation with choice exhibits a number of novel features. First, the density of the smallest clusters exhibits anomalous scaling. Second, both the small-size and the large-size tails of the density are overpopulated, at the expense of the density moderate-size clusters. We also study the complementary case where the smaller candidate clusters participates in the aggregation process, and find abundance of moderate clusters at the expense of small and large clusters. Additionally, we investigate aggregation processes with choice among multiple candidate clusters, and a symmetric implementation where the choice is between two pairs of clusters.
description: 12 pages, 11 figures
A theory of mass transfer in binary stars
Creators: name: Cehula, Jakub
name: Pejcha, Ondřej
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: Calculation of the mass transfer (MT) rate $\dot{M}_\text{d}$ of a Roche lobe overflowing star is a fundamental task in binary star evolution theory. Most of the existing MT prescriptions are based on a common set of assumptions that combine optically-thick and optically-thin regimes with different flow geometries. In this work, we develop a new model of MT based on the assumption that the Roche potential sets up a nozzle converging on the inner Lagrangian point and that the gas flows mostly along the axis connecting both stars. We derive a set of 1D hydrodynamic equations governing the gas flow with $\dot{M}_\text{d}$ determined as the eigenvalue of the system. The inner boundary condition directly relates our model to the structure of the donor obtained from 1D stellar evolution codes. We obtain algebraic solution for the polytropic equation of state (EOS), which gives $\dot{M}_\text{d}$ within a factor of 0.9 to 1.0 of existing optically-thick prescriptions and which reduces to the existing optically-thin prescription for isothermal gas. For a realistic EOS, we find that $\dot{M}_\text{d}$ differs by up to a factor of 4 from existing models. We illustrate the effects of our new MT model on $30\,M_\odot$ low-metallicity star undergoing intensive thermal time-scale MT and find that it is more likely to become unstable to L2 overflow and common-envelope evolution than for existing MT prescriptions. Our model provides a framework for including additional physics such as radiation or magnetic fields.
description: 20 pages, 16 figures. Submitted to MNRAS
Color-factor symmetry of the amplitudes of Yang-Mills and biadjoint scalar theory using perturbiner methods
Creators: name: Naculich, Stephen G.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Color-factor symmetry is a property of tree-level gauge-theory amplitudes containing at least one gluon. BCJ relations among color-ordered amplitudes follow directly from this symmetry. Color-factor symmetry is also a feature of biadjoint scalar theory amplitudes as well as of their equations of motion. In this paper, we present a new proof of color-factor symmetry using a recursive method derived from the perturbiner expansion of the classical equations of motion.
description: 20 pages, no figures; v2: additional references, version published in JHEP; v3: typo in eq. 4.36 corrected
Stability and instability towards delocalization in MBL systems
Creators: name: De Roeck, Wojciech
name: Huveneers, François
Publisher: name: arXiv
Year: 2016
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We propose a theory that describes quantitatively the (in)stability of fully MBL systems due to ergodic, i.e. delocalized, grains, that can be for example due to disorder fluctuations. The theory is based on the ETH hypothesis and elementary notions of perturbation theory. The main idea is that we assume as much chaoticity as is consistent with conservation laws. The theory describes correctly -even without relying on the theory of local integrals of motion (LIOM)- the MBL phase in 1 dimension at strong disorder. It yields an explicit and quantitative picture of the spatial boundary between localized and ergodic systems. We provide numerical evidence for this picture. When the theory is taken to its extreme logical consequences, it predicts that the MBL phase is destabilised in the long time limit whenever 1) interactions decay slower than exponentially in $d=1$ and 2) always in $d>1$. Finer numerics is required to assess these predictions.
description: 14 pages
title: Nachhaltigkeit und Gemeinwohl in Kommunen
title: Grundlagen – Instrumente – Praktiken
titleType: Subtitle
Creators: name: Bertelsmann Stiftung
name:  ICLEI European Secretariat GmbH
name: International Federation for the Economy for the Common Good e. V.
Publisher: name: Bertelsmann Stiftung
Year: 2022
Subjects: Nachhaltigkeit
Gemeinwohl
Kommune

description: Immer mehr Kommunen in Deutschland orientieren ihre strategische Entwicklung an den Leitbildern der Nachhaltigkeit oder des Gemeinwohls. Beide Konzepte ergänzen sich und können in integrierter Form entwickelt und umgesetzt werden. Das ist das zentrale Ergebnis einer Studie der Bertelsmann Stiftung, des Europasekretariats von ICLEI und des internationalen Vereins zur Förderung der Gemeinwohl-Ökonomie.
Interaction between linear polarized plane gravitational waves and a plane electromagnetic wave in the electromagnetic-gravity analogue
Creators: name: Falcón-Gomez, Enderson
name: De Falco, Vittorio
name: Abdalmalak, Kerlos Atia
name: Amor-Martín, Adrián
name: De La Rubia, Valentín
name: Santamaría-Botello, Gabriel
name: Muñoz, Luis Enrique García
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the interaction among gravitational and electromagnetic plane waves by means of an analogue electromagnetic model of gravity, where the gravitational properties are encoded in the electromagnetic properties of a material in flat space-time. In this setup, the variations in the metric tensor produced by the gravitational waves are codified as space-time-varying electromagnetic properties. We used an in-housed code based in the finite-difference time domain method to conduct numerical experiments, where we found that, when a monochromatic gravitational plane wave interacts with a narrow-band electromagnetic plane wave, an infinite number of sidebands, equally separated between themselves, are induced by the gravitational wave. Finally, we discuss possible future applications of this effect as an alternative method to directly detect gravitational waves.
description: 10 pages, 4 figures, 2 tables. Accepted for publication on Physical Review D
Wake excited in plasma by an ultra-relativistic point-like bunch
Creators: name: Stupakov, G.
name: Breizman, B.
name: Khudik, V.
name: Shvets, G.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: A plasma flow behind a relativistic electron bunch propagating through a cold plasma is found assuming that the transverse and longitudinal dimensions of the bunch are small and the bunch can be treated as a point charge. In addition, the bunch charge is assumed small. A simplified system of equations for the plasma electrons is derived and it is shown that, through a simple rescaling of variables, the bunch charge can be eliminated from the equations. These equations have a unique solution, with an ion cavity formed behind the driver. The equations are solved numerically and the scaling of the cavity dimensions with the driver charge is obtained. A numerical solution for the case of a positively charged driver is also found.
Breaking rotations without violating the KSS viscosity bound
Creators: name: Baggioli, Matteo
name: Cremonini, Sera
name: Early, Laura
name: Li, Li
name: Sun, Hao-Tian
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We revisit the computation of the shear viscosity to entropy ratio in a holographic p-wave superfluid model, focusing on the role of rotational symmetry breaking. We study the interplay between explicit and spontaneous symmetry breaking and derive a simple horizon formula for $η/s$, which is valid also in the presence of explicit breaking of rotations and is in perfect agreement with the numerical data. We observe that a source which explicitly breaks rotational invariance suppresses the value of $η/s$ in the broken phase, competing against the effects of spontaneous symmetry breaking. However, $η/s$ always reaches a constant value in the limit of zero temperature, which is never smaller than the Kovtun-Son-Starinets (KSS) bound, $1/4π$. This behavior appears to be in contrast with previous holographic anisotropic models which found a power-law vanishing of $η/s$ at small temperature. This difference is shown to arise from the properties of the near-horizon geometry in the extremal limit. Thus, our construction shows that the breaking of rotations itself does not necessarily imply a violation of the KSS bound.
description: 20 pages, 7 figures
Security of quantum key distribution with multiphoton components
Creators: name: Yin, Hua-Lei
name: Fu, Yao
name: Mao, Yingqiu
name: Chen, Zeng-Bing
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Most qubit-based quantum key distribution (QKD) protocols extract the secure key merely from single-photon component of the attenuated lasers. However, with the Scarani-Acin-Ribordy-Gisin 2004 (SARG04) QKD protocol, the unconditionally secure key can be extracted from the two-photon component by modifying the classical post-processing procedure in the BB84 protocol. Employing the merits of SARG04 QKD protocol and six-state preparation, one can extract secure key from the components of single photon up to four photons. In this paper, we provide the exact relations between the secure key rate and the bit error rate in a six-state SARG04 protocol with single-photon, two-photon, three-photon, and four-photon sources. By restricting the mutual information between the phase error and bit error, we obtain a higher secure bit error rate threshold of the multiphoton components than previous works. Besides, we compare the performances of the six-state SARG04 with other prepare-and-measure QKD protocols using decoy states.
description: 24 pages 2 figures
Radiation length imaging with high resolution telescopes
Creators: name: Stolzenberg, U.
name: Frey, A.
name: Schwenker, B.
name: Wieduwilt, P.
name: Marinas, C.
name: Lütticke, F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The construction of low mass vertex detectors with a high level of system integration is of great interest for next generation collider experiments. Radiation length images with a sufficient spatial resolution can be used to measure and disentangle complex radiation length $X$/$X_0$ profiles and contribute to the understanding of vertex detector systems. Test beam experiments with multi GeV particle beams and high-resolution tracking telescopes provide an opportunity to obtain precise 2D images of the radiation length of thin planar objects. At the heart of the $X$/$X_0$ imaging is a spatially resolved measurement of the scattering angles of particles traversing the object under study. The main challenges are the alignment of the reference telescope and the calibration of its angular resolution. In order to demonstrate the capabilities of $X$/$X_0$ imaging, a test beam experiment has been conducted. The devices under test were two mechanical prototype modules of the Belle II vertex detector. A data sample of 100 million tracks at $4\, \mathrm{GeV}$ has been collected, which is sufficient to resolve complex material profiles on the $30\,μ$m scale.
description: 4 pages, 5 figures, proceedings of the Vienna Conference of Instrumentation 2016 (VCI 2016)
Back-propagating the light of field stars to probe telescope mirrors aberrations
Creators: name: Soulez, Ferréol
name: Courbin, Frédéric
name: Unser, Michael
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We propose a wavefront-based method to estimate the PSF over the whole field of view. This method estimate the aberrations of all the mirrors of the telescope using only field stars. In this proof of concept paper, we described the method and present some qualitative results.
Kinematic analysis of the super-extended HI disk of the nearby spiral galaxy M83
Creators: name: Eibensteiner, Cosima
name: Bigiel, Frank
name: Leroy, Adam K.
name: Koch, Eric W.
name: Rosolowsky, Erik
name: Schinnerer, Eva
name: Sardone, Amy
name: Meidt, Sharon
name: de Blok, W. J. G
name: Thilker, David
name: Pisano, D. J.
name: Ott, Jürgen
name: Barnes, Ashley
name: Querejeta, Miguel
name: Emsellem, Eric
name: Puschnig, Johannes
name: Utomo, Dyas
name: Bešlic, Ivana
name: Brok, Jakob den
name: Faridani, Shahram
name: Glover, Simon C. O.
name: Grasha, Kathryn
name: Hassani, Hamid
name: Henshaw, Jonathan D.
name: Jiménez-Donaire, Maria J.
name: Kerp, Jürgen
name: Dale, Daniel A.
name: Kruijssen, J. M. Diederik
name: Laudage, Sebastian
name: Sanchez-Blazquez, Patricia
name: Smith, Rowan
name: Stuber, Sophia
name: Pessa, Ismael
name: Watkins, Elizabeth J.
name: Williams, Thomas G.
name: Winkel, Benjamin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present new HI observations of the nearby massive spiral galaxy M83, taken with the VLA at $21^{\prime\prime}$ angular resolution ($\approx500$ pc) of an extended ($\sim$1.5 deg$^2$) 10-point mosaic combined with GBT single dish data. We study the super-extended HI disk of M83 (${\sim}$50 kpc in radius), in particular disc kinematics, rotation and the turbulent nature of the atomic interstellar medium. We define distinct regions in the outer disk ($r_{\rm gal}>$central optical disk), including ring, southern area, and southern and northern arm. We examine HI gas surface density, velocity dispersion and non-circular motions in the outskirts, which we compare to the inner optical disk. We find an increase of velocity dispersion ($σ_v$) towards the pronounced HI ring, indicative of more turbulent HI gas. Additionally, we report over a large galactocentric radius range (until $r_{\rm gal}{\sim}$50 kpc) that $σ_v$ is slightly larger than thermal (i.e. $>8$km s$^{-1}$ ). We find that a higher star formation rate (as traced by FUV emission) is not always necessarily associated with a higher HI velocity dispersion, suggesting that radial transport could be a dominant driver for the enhanced velocity dispersion. We further find a possible branch that connects the extended HI disk to the dwarf irregular galaxy UGCA365, that deviates from the general direction of the northern arm. Lastly, we compare mass flow rate profiles (based on 2D and 3D tilted ring models) and find evidence for outflowing gas at r$_{\rm gal}$ $\sim$2 kpc, inflowing gas at r$_{\rm gal}$ $\sim$5.5 kpc and outflowing gas at r$_{\rm gal}$ $\sim$14 kpc. We caution that mass flow rates are highly sensitive to the assumed kinematic disk parameters, in particular, to the inclination.
description: accepted for publication in A&A; 16 pages, 12 figures (+8 pages appendix)
Realization and application of parity-time-symmetric oscillators in quantum regime
Creators: name: Li, Wenlin
name: Li, Chong
name: Song, Heshan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Although people have already artificially formed parity--time ($\mathcal{PT}$) symmetry with gain and loss in a balanced manner, it is still a defect that the gain is restricted to semi--classical but not full quantum. Here we propose and analyze a theoretical scheme to realize full quantum oscillator $\mathcal{PT}$--symmetry. The quantum gain is provided by a dissipation optical cavity with blue detuned laser field. After adiabatically eliminating the cavity modes, we give an effective master equation, which is a more complete quantum description compared with non--Hermitian Hamiltonian, to reveal the quantum behaviors of such a gain oscillator. This kind of $\mathcal{PT}$--symmetry can eliminate the dissipation effect in quantum regime. As examples, we finally apply $\mathcal{PT}$--symmetric oscillators to enhance optomechanically induced transparency and to preserve oscillator non--classical state.
The SUPERCOLD-CGM survey: \\ I. Probing the extended CO(4-3) Emission of the Circumglactic medium in a sample of 10 Enormous Ly$α$ Nebulae at $z\sim2$
Creators: name: Li, Jianrui
name: Emonts, Bjorn H. C.
name: Cai, Zheng
name: Li, Jianan
name: Battaia, Fabrizio Arrigoni
name: Prochaska, Jason X
name: Yoon, Ilsang
name: Lehnert, Matthew D.
name: Sarazin, Craig
name: Wu, Yunjing
name: Lacy, Mark
name: Mason, Brian
name: Massingill, Kyle
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: To understand how massive galaxies at high-$z$ co-evolve with enormous reservoirs of halo gas, it is essential to study the coldest phase of the circum-galactic medium (CGM), which directly relates to stellar growth. The SUPERCOLD-CGM survey is the first statistical survey of cold molecular gas on CGM scales. We present ALMA+ACA observations of CO(4-3) and continuum emission from 10 Enormous Ly$α$ Nebula (ELANe) around ultraluminous type-I QSOs at $z\sim2$. We detect CO(4-3) in 100$\%$ of our targets, with 60$\%$ showing extended CO on scales of 15$-$100 kpc. Q1228+3128 reveals the most extended CO(4-3) reservoir of $\sim$100 kpc and is the only radio-loud target in our sample. The CO reservoir is located along the radio axis, which could indicate a link between the inner radio-jet and cold halo gas. For the other five radio-quiet ELANe, four of them show extended CO(4-3) predominantly in the direction of their companions. These extended CO(4-3) reservoirs identify enrichment of the CGM, and may potentially contribute to widespread star formation. However, there is no evidence from CO(4-3) for diffuse molecular gas spread across the full extent of the Ly$α$ nebulae. One target in our sample (Q0107) shows significant evidence for a massive CO disk associated with the QSO. Moreover, 70$\%$ of our QSO fields contain at least one CO companion, two of which reveal extended CO emission outside the ELANe. Our results provide insight into roles of both the cold CGM and companions in driving the early evolution of massive galaxies.
description: Accepted for publication in ApJ. 27 pages, 16 figures
Controllable spin splitting in 2D Ferroelectric few-layer ${$γ}$-GeSe
Creators: name: Shi, Shuyi
name: Hao, Kuan-Rong
name: Ma, Xing-Yu
name: Yan, Qing-Bo
name: Su, Gang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: $γ$-GeSe is a new type of layered bulk material that was recently successfully synthesized. By means of density functional theory first-principles calculations, we systematically studied the physical properties of two-dimensional (2D) few-layer $γ$-GeSe. It is found that few-layer $γ$-GeSe are semiconductors with band gaps decreasing with increasing layer number; and 2D $γ$-GeSe with layer number $n \geq 2$ are ferroelectric with rather low transition barriers, consistent with the sliding ferroelectric mechanism. Particularly, spin-orbit coupling induced spin splitting is observed at the top of the valence band, which can be switched by the ferroelectric reversal; furthermore, their negative piezoelectricity also enables the regulation of spin splitting by strain. Finally, excellent optical absorption was also revealed. These intriguing properties make 2D few-layer $γ$-GeSe promising in spintronic and optoelectric applications.
description: 18 pages,6 figures
Uniform stability of recovering the Sturm-Liouville operators with frozen argument
Creators: name: Kuznetsova, Maria
Publisher: name: arXiv
Year: 2023
Subjects: subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: 34K29, 34A55

description: In the paper, we study the problem of recovering the Sturm--Liouville operator with frozen argument from its spectrum and additional data. For this inverse problem, we establish a substantial property of the uniform stability, which consists in that the potential depends Lipschitz continuously on the input data.
Molecular Gas Along a Bright H-alpha Filament in 2A 0335+096 Revealed by ALMA
Creators: name: Vantyghem, A. N.
name: McNamara, B. R.
name: Russell, H. R.
name: Hogan, M. T.
name: Edge, A. C.
name: Nulsen, P. E. J.
name: Fabian, A. C.
name: Combes, F.
name: Salome, P.
name: Baum, S. A.
name: Donahue, M.
name: Main, R. A.
name: Murray, N. W.
name: O'Connell, R. W.
name: O'Dea, C. P.
name: Oonk, J. B. R.
name: Parrish, I. J
name: Sanders, J. S.
name: Tremblay, G.
name: Voit, G. M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present ALMA CO(1-0) and CO(3-2) observations of the brightest cluster galaxy (BCG) in the 2A 0335+096 galaxy cluster (z = 0.0346). The total molecular gas mass of (1.13+/-0.15) x 10^9 M_sun is divided into two components: a nuclear region and a 7 kpc long dusty filament. The central molecular gas component accounts for (3.2+/-0.4) x 10^8 M_sun of the total supply of cold gas. Instead of forming a rotationally-supported ring or disk, it is composed of two distinct, blueshifted clumps south of the nucleus and a series of low-significance redshifted clumps extending toward a nearby companion galaxy. The velocity of the redshifted clouds increases with radius to a value consistent with the companion galaxy, suggesting that an interaction between these galaxies <20 Myr ago disrupted a pre-existing molecular gas reservoir within the BCG. Most of the molecular gas, (7.8+/-0.9) x 10^8 M_sun, is located in the filament. The CO emission is co-spatial with a 10^4 K emission-line nebula and soft X-rays from 0.5 keV gas, indicating that the molecular gas has cooled out of the intracluster medium over a period of 25-100 Myr. The filament trails an X-ray cavity, suggesting that the gas has cooled from low entropy gas that has been lifted out of the cluster core and become thermally unstable. We are unable to distinguish between inflow and outflow along the filament with the present data. Cloud velocities along the filament are consistent with gravitational free-fall near the plane of the sky, although their increasing blueshifts with radius are consistent with outflow.
description: 21 pages, 14 figures, accepted to ApJ
On very short and intense laser-plasma interactions
Creators: name: Fiore, Gaetano
Publisher: name: arXiv
Year: 2016
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 35Qxx, 76Wxx, 82D10

description: We briefly report on some results regarding the impact of very short and intense laser pulses on a cold, low-density plasma initially at rest, and the consequent acceleration of plasma electrons to relativistic energies. Locally and for short times the pulse can be described by a transverse plane electromagnetic travelling-wave and the motion of the electrons by a purely Magneto-Fluido-Dynamical (MFD) model with a very simple dependence on the transverse electromagnetic potential, while the ions can be regarded as at rest; the Lorentz-Maxwell and continuity equations are reduced to the Hamilton equations of a Hamiltonian system with 1 degree of freedom, in the case of a plasma with constant initial density, or a collection of such systems otherwise. We can thus describe both the well-known "wakefield" behind the pulse and the recently predicted "slingshot effect", i.e. the backward expulsion of high energy electrons just after the laser pulse has hit the surface of the plasma.
description: Latex file, 15 pages, 6 figures