cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Dust and Gas environment of the young embedded cluster IRAS 18511+0146
Creators: name: Vig, S.
name: Testi, L.
name: Walmsley, C. M.
name: Cesaroni, R.
name: Molinari, S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: IRAS 18511+0146 is a young embedded (proto)cluster located at 3.5 kpc surrounding what appears to be an intermediate mass protostar. In this paper, we investigate the nature of cluster members (two of which are believed to be the most massive and luminous) using imaging and spectroscopy in the near and mid-infrared. The brightest point-like object associated with IRAS 18511+0146 is referred to as S7 in the present work (designated UGPS J185337.88+015030.5 in the UKIRT Galactic Plane survey). Seven of the nine objects show rising spectral energy distributions (SED) in the near-infrared, with four objects showing Br-gamma emission. Three members: S7, S10 (also UGPS J185338.37+015015.3) and S11 (also UGPS J185338.72+015013.5) are bright in mid-infrared with diffuse emission being detected in the vicinity of S11 in PAH bands. Silicate absorption is detected towards these three objects, with an absorption maximum between 9.6 and 9.7 um, large optical depths (1.8-3.2), and profile widths of 1.6-2.1 um. The silicate profiles of S7 and S10 are similar, in contrast to S11 (which has the largest width and optical depth). The cold dust emission investigated using Herschel HiGal peaks at S7, with temperature at 26 K and column density N(H2) ~ 7 x 10^(22) cm^(-2). The bolometric luminosity of IRAS 18511 region is L ~ 1.8 x 10^4 L_sun. S7 is the main contributor to the bolometric luminosity, with L (S7) > 10^4 L_sun. S7 is a high mass protostellar object with ionised stellar winds, evident from the correlation between radio and bolometric luminosity as well as the asymmetric Br-gamma profile. The differences in silicate profiles of S7 and S11 could be due to different radiation environment as we believe the former to be more massive and in an earlier phase than the latter.
description: Accepted for publication in Astronomy & Astrophysics
Does the gamma-ray signal from the central Milky Way indicate Sommerfeld enhancement of dark matter annihilation?
Creators: name: Chan, Man Ho
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Recently, Daylan et al. (2014) show that the GeV gamma-ray excess signal from the central Milky Way can be explained by the annihilation of $\sim 40$ GeV dark matter through $b\bar{b}$ channel. Based on the morphology of the gamma-ray flux, the best-fit inner slope of the dark matter density profile is $γ=1.26$. However, recent analyses of Milky Way dark matter profile favor $γ=0.6-0.8$. In this article, we show that the GeV gamma-ray excess can also be explained by the Sommerfeld-enhanced dark matter annihilation through $b\bar{b}$ channel with $γ=0.85-1.05$. We constrain the parameters of the Sommerfeld-enhanced annihilation by using the data from Fermi-LAT. We also show that the predicted gamma-ray fluxes emitted from dwarf galaxies generally satisfy the recent upper limits of gamma-ray fluxes detected by Fermi-LAT.
description: Accepted for publication in Research in Astronomy and Astrophysics
Measurement of the differential $\mathrm{t\bar{t}}$ production cross section as a function of the jet mass and extraction of the top quark mass in hadronic decays of boosted top quarks
Creators: name: CMS Collaboration
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A measurement of the jet mass distribution in hadronic decays of Lorentz-boosted top quarks is presented. The measurement is performed in the lepton+jets channel of top quark pair production ($\mathrm{t\bar{t}}$) events, where the lepton is an electron or muon. The products of the hadronic top quark decay are reconstructed using a single large-radius jet with transverse momentum greater than 400 GeV. The data were collected with the CMS detector at the LHC in proton-proton collisions and correspond to an integrated luminosity of 138 fb$^{-1}$. The differential $\mathrm{t\bar{t}}$ production cross section as a function of the jet mass is unfolded to the particle level and is used to extract the top quark mass. The jet mass scale is calibrated using the hadronic W boson decay within the large-radius jet. The uncertainties in the modelling of the final state radiation are reduced by studying angular correlations in the jet substructure. These developments lead to a significant increase in precision, and a top quark mass of 173.06 $\pm$ 0.84 GeV.
description: Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-21-012 (CMS Public Pages)
Cocoon cooling emission in neutron star mergers
Creators: name: Hamidani, Hamid
name: Ioka, Kunihito
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In the gravitational wave event GW170817, there was a $\sim 10$ hours gap before electromagnetic (EM) observations, without detection of the cocoon. The cocoon is heated by a \textit{short} gamma-ray burst (\textit{s}GRB) jet propagating through the ejecta of a Neutron Star (NS) merger, and a part of the cocoon escapes the ejecta with an opening angle of $20^{\circ}$--$30^{\circ}$. Here we model the cocoon and calculate its EM emission. Our 2D hydrodynamic simulations suggest that the density and energy distributions, after entering homologous expansion, are well-fitted with power-law functions, in each of the relativistic and non-relativistic parts of the escaped cocoon. Modeling these features, we calculate the cooling emission analytically. We find that the cocoon outshines the r-process kilonova/macronova at early times (10--10$^{3}$ s), peaking at UV bands. The relativistic velocity of the cocoon's photosphere is measurable with instruments such as Swift, ULTRASAT and LSST. We also imply that energetic cocoons, including failed jets, might be detected as X-ray flashes. Our model clarifies the physics and parameter dependence, covering a wide variety of central engines and ejecta of NS mergers and \textit{s}GRBs in the multi-messenger era.
description: 29 pages, 10 figures, and 3 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS)
title: A Lasting Crisis affects R&D decisions of smaller firms
title: the Greek experience
titleType: Subtitle
Creators: name: Giotopoulos, Ioannis
name: Kritikos, Alexander S.
name: Tsakanikas, Aggelos
Publisher: name: Universität Potsdam
Year: 2022
Subjects: subject: 330 Wirtschaft

description: We use the prolonged Greek crisis as a case study to understand how a lasting economic shock affects the innovation strategies of firms in economies with moderate innovation activities. Adopting the 3-stage CDM model, we explore the link between R&D, innovation, and productivity for different size groups of Greek manufacturing firms during the prolonged crisis. At the first stage, we find that the continuation of the crisis is harmful for the R&D engagement of smaller firms while it increased the willingness for R&D activities among the larger ones. At the second stage, among smaller firms the knowledge production remains unaffected by R&D investments, while among larger firms the R&D decision is positively correlated with the probability of producing innovation, albeit the relationship is weakened as the crisis continues. At the third stage, innovation output benefits only larger firms in terms of labor productivity, while the innovation-productivity nexus is insignificant for smaller firms during the lasting crisis.
description: CEPA Discussion Papers; 49
Reachability Analysis and Safety Verification of Neural Feedback Systems via Hybrid Zonotopes
Creators: name: Zhang, Yuhao
name: Xu, Xiangru
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: Hybrid zonotopes generalize constrained zonotopes by introducing additional binary variables and possess some unique properties that make them convenient to represent nonconvex sets. This paper presents novel hybrid zonotope-based methods for the reachability analysis and safety verification of neural feedback systems. Algorithms are proposed to compute the input-output relationship of each layer of a feedforward neural network, as well as the exact reachable sets of neural feedback systems. In addition, a sufficient and necessary condition is formulated as a mixed-integer linear program to certify whether the trajectories of a neural feedback system can avoid unsafe regions. The proposed approach is shown to yield a formulation that provides the tightest convex relaxation for the reachable sets of the neural feedback system. Complexity reduction techniques for the reachable sets are developed to balance the computation efficiency and approximation accuracy. Two numerical examples demonstrate the superior performance of the proposed approach compared to other existing methods.
description: 8 pages, 4 figures
Registered Nurses’ use of a National Early Warning Score: An interpretative hermeneutic phenomenological study
Creators: name: Nadaf, Claire
Publisher: name: London South Bank University
Year: 2023

description: Background: The National Early Warning Score (NEWS) was introduced in the U.K. to address the patient safety risk of failing to recognise and act on patient deterioration promptly. However, patients still deteriorate unnoticed. Registered Nurses are responsible for patient monitoring and are the main users of NEWS. Aim: To explore Registered Nurses’ experiences and perceptions of using NEWS in the U.K. as part of the recognition and management of acute adult patient deterioration. Methodology: Sixteen Registered Nurses from a U.K. NHS Trust were interviewed using an interpretative hermeneutic phenomenological approach, guided by Gadamerian philosophy. In-depth interviews formed part of a Gadamerian spiral, interpreted to gain new understanding through a fusion of horizons to reveal the story of using NEWS in clinical practice and the meaning for nurses. Findings: The story revealed three pinch points of risk in clinical practice: delegation of vital sign monitoring to healthcare assistants with uncertainty and delayed escalation; over-reliance on NEWS and a culture-based deference to expertise by Junior Nurses; and Senior Nurses' potential over-confidence in selfmanaging deteriorating patients. Workplace culture surrounding NEWS revealed constant compromises and lack of learning opportunities with a potential consequence of future skills gaps in the nursing workforce. Conclusions: When using NEWS, failure to recognise the risks associated with the three pinch points threatens patient safety. Wrong decisions at these points may lead to missed chances in preventing deterioration. Incorrect judgments may lead to unrecognised patient deterioration or inappropriate management leading to preventable adverse events. Recommendations for practice: The nursing profession and health service need to: • address education gaps in the registered/unregistered nursing workforce relating to the recognition and management of deteriorating patients, to ensure safe use of NEWS; • foster a culture that supports, values and develops nurses' clinical judgment to enhance patient safety
A numerical study of interactions and stellar bars
Creators: name: Martinez-Valpuesta, Inma
name: Aguerri, J. Alfonso L.
name: González-García, A. César
name: Vecchia, Claudio Dalla
name: Stringer, Martin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: For several decades it has been known that stellar bars in disc galaxies can be triggered by interactions, or by internal processes such as dynamical instabilities. In this work, we explore the differences between these two mechanisms using numerical simulations. We perform two groups of simulations based on isolated galaxies, one group in which a bar develops naturally, and another group in which the bar could not develop in isolation. The rest of the simulations recreate 1:1 coplanar fly-by interactions computed with the impulse approximation. The orbits we use for the interactions represent the fly-bys in groups or clusters of different masses accordingly to the velocity of the encounter. In the analysis we focus on bars' amplitude, size, pattern speed and their rotation parameter, ${\cal R}=R_{CR}/R_{bar}$. The latter is used to define fast (${\cal R}<1.4$) and slow rotation (${\cal R}>1.4$). Compared with equivalent isolated galaxies we find that bars affected or triggered by interactions: (i) remain in the slow regime for longer; (ii) are more boxy in face-on views; (iii) they host kinematically hotter discs. Within this set of simulations we do not see strong differences between retrograde or prograde fly-bys. We also show that slow interactions can trigger bar formation.
description: 12 pages, 7 figures. Accepted for publication in MNRAS
Physics Beyond the Standard Model with Future X-ray Observatories: Projected Constraints on Very-Light Axion-Like Particles with $Athena$ and $AXIS$
Creators: name: Sisk-Reynés, Júlia
name: Reynolds, Christopher S.
name: Parker, Michael L.
name: Matthews, James H.
name: Marsh, M. C. David
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Axion-Like Particles (ALPs) are well-motivated extensions of the Standard Model of Particle Physics and a generic prediction of some string theories. X-ray observations of bright Active Galactic Nuclei (AGN) hosted by rich clusters of galaxies are excellent probes of very-light ALPs, with masses $\mathrm{log}(m_\mathrm{a}/\mathrm{eV}) < -12.0$. We evaluate the potential of future X-ray observatories, particularly $Athena$ and the proposed $AXIS$, to constrain ALPs via observations of cluster-hosted AGN, taking NGC 1275 in the Perseus cluster as our exemplar. Assuming perfect knowledge of instrument calibration, we show that a modest exposure (200-ks) of NGC 1275 by $Athena$ permits us to exclude all photon-ALP couplings $g_\mathrm{aγ} > 6.3 \times 10^{-14} \ {\mathrm{GeV}}^{-1}$ at the 95% level, as previously shown by $Conlon \ et \ al. \ (2018)$, representing a factor of 10 improvement over current limits. We then proceed to assess the impact of realistic calibration uncertainties on the $Athena$ projection by applying a standard $Cash$ likelihood procedure, showing the projected constraints on $g_\mathrm{aγ}$ weaken by a factor of 10 (back to the current most sensitive constraints). However, we show how the use of a deep neural network can disentangle the energy-dependent features induced by instrumental miscalibration and those induced by photon-ALP mixing, allowing us to recover most of the sensitivity to the ALP physics. In our explicit demonstration, the machine learning applied allows us to exclude $g_\mathrm{aγ} > 2.0 \times 10^{-13} \ {\mathrm{GeV}}^{-1}$, complementing the projected constraints of next-generation ALP dark matter birefringent cavity searches for very-light ALPs. Finally, we show that a 200-ks $AXIS$/on-axis observation of NGC 1275 will tighten the current best constraints on very-light ALPs by a factor of 3.
description: 22 pages, 10 figures, 3 tables. Accepted for publication at the Astrophysical Journal. Comments welcome
The Electronic States of a Double Carbon Vacancy Defect in Pyrene: A Model Study for Graphene
Creators: name: Machado, Francisco B. C.
name: Aquino, Adélia J. A.
name: Lischka, Hans
Publisher: name: arXiv
Year: 2016
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The electronic states occurring in a double vacancy defect for graphene nanoribbons have been calculated in detail based on a pyrene model. Extended ab initio calculations using the MR configuration interaction (MRCI) method have been performed to describe in a balanced way the manifold of electronic states derived from the dangling bonds created by initial removal of two neighboring carbon atoms from the graphene network. In total, this study took into account the characterization of 16 electronic states (eight singlets and eight triplets) considering unrelaxed and relaxed defect structures. The ground state was found to be of 1Ag character with around 50% closed shell character. The geometry optimization process leads to the formation of two five-membered rings in a pentagon octagon pentagon structure. The closed shell character increases thereby to ~70%, the analysis of unpaired density shows only small contributions confirming the chemical stability of that entity. For the unrelaxed structure the first five excited states (3B3g, 3B2u, 3B1u, 3Au and 1Au) are separated from the ground state by less than 2.5 eV. For comparison, unrestricted density functional theory (DFT) calculations using several types of functionals have been performed within different symmetry subspaces defined by the open shell orbitals. Comparison with the MRCI results gave good agreement in terms of finding the 1Ag state as ground state and in assigning the lowest excited states. Linear interpolation curves between the unrelaxed and relaxed defect structures also showed good agreement between the two classes of methods opening up the possibilities of using extended nanoflakes for multistate investigations at DFT level.
Gibbs-Bogoliubov inequality on Nishimori line
Creators: name: Okuyama, Manaka
name: Ohzeki, Masayuki
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Probability (math.PR)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The Gibbs-Bogoliubov inequality states that the free energy of a system is always lower than that calculated by a trial function. In this study, we show that a counterpart of the Gibbs-Bogoliubov inequality holds on the Nishimori line for Ising spin-glass models with Gaussian randomness. Our inequality states that the quenched free energy of a system is always lower than that calculated using a quenched trial function. The key component of the proof is the convexity of the pressure function $\mathbb{E}\left[\log Z_{} \right]$ with respect to the parameters along the Nishimori line, which differs from the conventional convexity with respect to the inverse temperature. When our inequality was applied to mean-field models, such as the Sherrington-Kirkpatrick model and $p$-spin model, the bound coincided with the replica-symmetric solution indicating that the equality holds.
description: 9 pages, 0 figure
Multipole analysis on stationary massive vector and symmetric tensor fields
Creators: name: Wu, Bofeng
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The multipole expansions for massive vector and symmetric tensor fields in the region outside spatially compact stationary sources are obtained by using the symmetric and trace-free formalism in terms of the irreducible Cartesian tensors, and the closed-form expressions for the source multipole moments are provided. The expansions show a Yukawa-like dependence on the massive parameters of the fields, and the integrals of the stationary source multipole moments are all modulated by a common radial factor related to the source distribution. For stationary massive vector field, there are two types of ``magnetic'' multipole moments, among which one is the generalization of that of the magnetostatic field, and another, being an additional set of multipole moments of the stationary massive vector field, can not be transformed away. As to the stationary massive symmetric tensor field, its multipole expansion is presented when the trace of its spatial part is specified, where besides the counterparts of the mass and spin multipole moments of massless symmetric tensor field, three additional sets of multipole moments also appear. The multipole expansions of the tensor field under two typical cases are discussed, where it is shown that if the spatial part of the tensor field is trace-free, the monopole and dipole moments in the corresponding expansion will vanish.
description: 14 pages
Magnetization Dynamics in Synthetic Antiferromagnets with Perpendicular Magnetic Anisotropy
Creators: name: Huang, Dingbin
name: Zhang, Delin
name: Kim, Yun
name: Wang, Jian-Ping
name: Wang, Xiaojia
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Understanding the rich physics of magnetization dynamics in perpendicular synthetic antiferromagnets (p-SAFs) is crucial for developing next-generation spintronic devices. In this work, we systematically investigate the magnetization dynamics in p-SAFs combining time-resolved magneto-optical Kerr effect (TR-MOKE) measurements with theoretical modeling. These model analyses, based on a Landau-Lifshitz-Gilbert approach incorporating exchange coupling, provide details about the magnetization dynamic characteristics including the amplitudes, directions, and phases of the precession of p-SAFs under varying magnetic fields. These model-predicted characteristics are in excellent quantitative agreement with TR-MOKE measurements on an asymmetric p-SAF. We further reveal the damping mechanisms of two procession modes co-existing in the p-SAF and successfully identify individual contributions from different sources, including Gilbert damping of each ferromagnetic layer, spin pumping, and inhomogeneous broadening. Such a comprehensive understanding of magnetization dynamics in p-SAFs, obtained by integrating high-fidelity TR-MOKE measurements and theoretical modeling, can guide the design of p-SAF-based architectures for spintronic applications.
description: Published in Phys. Rev. B. Manuscript: 28 pages, 5 figures; Supplemantal Material: 11 pages, 4 figures
Report on Progress in Physics: Observation of the Breit-Wheeler Process and Vacuum Birefringence in Heavy-Ion Collisions
Creators: name: Brandenburg, James Daniel
name: Seger, Janet
name: Xu, Zhangbu
name: Zha, Wangmei
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: This Report reviews the effort over several decades to observe the linear Breit-Wheeler process ($γγ\rightarrow e^+e^-$) and vacuum birefringence in high-energy particle and heavy-ion collider experiment. This Report, motivated by STAR's recent observations, attempts to summarize the key issues related to the interpretation of polarized $γγ\rightarrow l^+l^-$ measurements in high-energy experiments. To that end, we start by reviewing the historical context and essential theoretical developments, before focusing on the decades of progress made in high-energy collider experiments. Special attention is given to the evolution in experimental approaches in response to various challenges and the demanding detector capabilities required to unambiguously identify the linear Breit-Wheeler process and to detect the signatures of vacuum birefringence. We close the report with a discussion, followed by a look at near-future opportunities for utilizing these discoveries and for testing QED in previously unexplored regimes.
Mapping the effect of defect-induced strain disorder on the Dirac states of topological insulators
Creators: name: Storz, Oliver
name: Cortijo, Alberto
name: Wilfert, Stefan
name: Kokh, Konstantin A.
name: Tereshchenko, Oleg E.
name: Vozmediano, María A. H.
name: Bode, Matthias
name: Guinea, Francisco
name: Sessi, Paolo
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We provide a detailed microscopic characterization of the influence of defects-induced disorder onto the Dirac spectrum of three dimensional topological insulators. By spatially resolved Landau-levels spectroscopy measurements, we reveal the existence of nanoscale fluctuations of both the Dirac point energy as well as of the Dirac-fermions velocity which is found to spatially change in opposite direction for electrons and holes, respectively. These results evidence a scenario which goes beyond the existing picture based on chemical potential fluctuations. The findings are consistently explained by considering the microscopic effects of local stain introduced by defects, which our model calculations show to effectively couple to topological states, reshaping their Dirac-like dispersion over a large energy range. In particular, our results indicate that the presence of microscopic spatially varying stain, inevitably present in crystals because of the random distribution of defects, effectively couple to topological states and should be carefully considered for correctly describing the effects of disorder.
Enumerative geometry of surfaces and topological strings
Creators: name: Brini, Andrea
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Algebraic Geometry (math.AG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: This survey covers recent developments on the geometry and physics of Looijenga pairs, namely pairs $(X,D)$ with $X$ a complex algebraic surface and $D$ a singular anticanonical divisor in it. I will describe a surprising web of correspondences linking together several a priori distant classes of enumerative invariants associated to $(X,D)$, including the log Gromov--Witten invariants of the pair, the Gromov--Witten invariants of an associated higher dimensional Calabi--Yau variety, the open Gromov--Witten invariants of certain special Lagrangians in toric Calabi--Yau threefolds, the Donaldson--Thomas theory of a class of symmetric quivers, and certain open and closed BPS-type invariants. I will also discuss how these correspondences can be effectively used to provide a complete closed-form solution to the calculation of all these invariants.
description: Solicited review prepared for submission to IJMPA, surveying the content of arXiv:1908.04371, arXiv:2011.08830, arXiv:2012.10353 and arXiv:2201.01645 but with a presentation slightly more inclined towards a physics readership. 51 pages, 13 figures
Non-vanishing Superpotentials in Heterotic String Theory and Discrete Torsion
Creators: name: Buchbinder, Evgeny I.
name: Ovrut, Burt A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the non-perturbative superpotential in E_8 x E_8 heterotic string theory on a non-simply connected Calabi-Yau manifold X, as well as on its simply connected covering space \tilde{X}. The superpotential is induced by the string wrapping holomorphic, isolated, genus 0 curves. According to the residue theorem of Beasley and Witten, the non-perturbative superpotential must vanish in a large class of heterotic vacua because the contributions from curves in the same homology class cancel each other. We point out, however, that in certain cases the curves treated in the residue theorem as lying in the same homology class, can actually have different area with respect to the physical Kahler form and can be in different homology classes. In these cases, the residue theorem is not directly applicable and the structure of the superpotential is more subtle. We show, in a specific example, that the superpotential is non-zero both on \tilde{X} and on X. On the non-simply connected manifold X, we explicitly compute the leading contribution to the superpotential from all holomorphic, isolated, genus 0 curves with minimal area. The reason for the non-vanishing of the superpotental on X is that the second homology class contains a finite part called discrete torsion. As a result, the curves with the same area are distributed among different torsion classes and, hence, do not cancel each other.
description: 44 pages
Influence of a cosmic string on the rate of pairs produced by the Coulomb potential
Creators: name: Belbaki, B.
name: Bounames, A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study particle creation phenomenon by the Coulomb potential of an external electric field in the presence of a gravitational field of a static cosmic string. For that, the generalized Klein-Gordon and Dirac equations are solved, and by using the Bogoliubov transformation we calculate the probability and the number density of created particles. It is shown that the presence of the cosmic string enhances the particle production. For the grand unified theory (GUT) cosmic string, the production of spinless particles is possible if the Coulomb potential nucleus charge $Z\geq206$, and for spin-1/2 particles if $Z\geq275$.
description: 26 pages, 5 figures, published version
Polarization memory in the nonpolar magnetic ground state of multiferroic CuFeO2
Creators: name: Beilsten-Edmands, J.
name: Magorrian, S. J.
name: Foronda, F. R.
name: Prabhakaran, D.
name: Radaelli, P. G.
name: Johnson, R. D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We investigate polarization memory effects in single-crystal CuFeO2, which has a magnetically-induced ferroelectric phase at low temperatures and applied B fields between 7.5 and 13 T. Following electrical poling of the ferroelectric phase, we find that the nonpolar collinear antiferromagnetic ground state at B = 0 T retains a strong memory of the polarization magnitude and direction, such that upon re-entering the ferroelectric phase a net polarization of comparable magnitude to the initial polarization is recovered in the absence of external bias. This memory effect is very robust: in pulsed-magnetic-field measurements, several pulses into the ferroelectric phase with reverse bias are required to switch the polarization direction, with significant switching only seen after the system is driven out of the ferroelectric phase and ground state either magnetically (by application of B > 13 T) or thermally. The memory effect is also largely insensitive to the magnetoelastic domain composition, since no change in the memory effect is observed for a sample driven into a single-domain state by application of stress in the [1-10] direction. On the basis of Monte Carlo simulations of the ground state spin configurations, we propose that the memory effect is due to the existence of helical domain walls within the nonpolar collinear antiferromagnetic ground state, which would retain the helicity of the polar phase for certain magnetothermal histories.
description: 9 pages, 7 figures
Carroll fermions in two dimensions
Creators: name: Banerjee, Aritra
name: Dutta, Sudipta
name: Mondal, Saikat
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Carroll symmetry is a very powerful characteristic of generic null surfaces, as it replaces the usual Poincaré algebra with a vanishing speed of light version thereof. These symmetries have found universal applications in the physics of null manifolds as they arise in diverse situations ranging from black hole horizons to condensed matter systems with vanishing Fermi velocities. In this work, we concentrate on fermions living on two dimensional ($2d$) null manifolds and explore the Carroll invariant structure of the associated field theories in a systematic manner. The free massless versions of these fermions are shown to exhibit $2d$ Conformal Carroll or equivalently the $3d$ Bondi-Metzner-Sachs (BMS) algebra as their symmetry. Due to the degenerate nature of the manifold, we show the presence of two distinct classes of Clifford Algebras. We also find that in two dimensions there are two distinct fermion actions. We study discrete and continuous symmetries of both theories, and quantize them using highest weight representation of the vacuum. We also discuss how the symmetries of $2d$ free fermion CFTs can be continually deformed by infinite boosts or degenerate linear transformations on coordinates, leading to the corresponding BMS invariant theory at singular points.
description: 37 pages, no figures
Revisiting Kinematic Fast Dynamo in 3-dimensional magnetohydrodynamic plasmas: Dynamo transition from non-Helical to Helical flows
Creators: name: Biswas, Shishir
name: Ganesh, Rajaraman
Publisher: name: arXiv
Year: 2022
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Computational Physics (physics.comp-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Dynamos wherein magnetic field is produced from velocity fluctuations are fundamental to our understanding of several astrophysical and/or laboratory phenomena. Though fluid helicity is known to play a key role in the onset of dynamo action, its effect is yet to be fully understood. In this work, a fluid flow proposed recently [Yoshida et al. Phys. Rev. Lett. 119, 244501 (2017)] is invoked such that one may inject zero or finite fluid helicity using a control parameter, at the beginning of the simulation. Using a simple kinematic fast dynamo model, we demonstrate unambiguously the strong dependency of short scale dynamo on fluid helicity. In contrast to conventional understanding, it is shown that fluid helicity does strongly influence the physics of short scale dynamo. To corroborate our findings, late time magnetic field spectra for various values of injected fluid helicity is presented along with rigorous ``geometric'' signatures of the 3D magnetic field surfaces, which shows a transition from ``untwisted'' to ``twisted'' sheet to ``cigar'' like configurations. It is also shown that one of the most studied ABC dynamo model is not the ``fastest'' dynamo model for problems with lower magnetic Reynolds number. This work brings out, for the first time, the role of fluid helicity in moving from ``non-dynamo'' to ``dynamo'' regime systematically.
Cornering Large-$N_c$ QCD with Positivity Bounds
Creators: name: Fernandez, Clara
name: Pomarol, Alex
name: Riva, Francesco
name: Sciotti, Francesco
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The simple analytic structure of meson scattering amplitudes in the large-$N_c$ limit, combined with positivity of the spectral density, provides precise predictions on low-energy observables. Building upon previous studies, we explore the allowed regions of chiral Lagrangian parameters and meson couplings to pions. We reveal a structure of kinks at all orders in the chiral expansion and develop analytical tools to show that kinks always correspond to amplitudes with a single light pole. We build (scalar- and vector-less) deformations of the Lovelace-Shapiro and Coon UV-complete amplitudes, and show that they lie close to the boundaries. Moreover, constraints from crossing-symmetry imply that meson couplings to pions become smaller as their spin increases, providing an explanation for the success of Vector Meson Dominance and holographic QCD. We study how these conclusions depend on assumptions about the high-energy behavior of amplitudes. Finally, we emphasize the complementarity between our results and Lattice computations in the exploration of large-$N_c$ QCD.
description: 38 pages, 7 figures
D4.1 State-of-the-art Analysis: mapping of the policy landscape for learning opportunities for researchers on open and responsible research and innovation
Creators: name: Salnikova, Asya
name: Brandstetter-Kunc, Adam
Publisher: name: Zenodo
Year: 2023
Subjects: Open and Responsible Research and Innovation
Open Science
Mapping policies

description: The current document, titled “State-of-the-art Analysis: mapping of the policy landscape for learning opportunities for researchers on open and responsible research and innovation”, was developed within the framework of the PATTERN project which is funded by the Horizon Europe Research and Innovation Programme under Grant Agreement No 101094416. 

The purpose of this Deliverable is to describe and analyse the existing policies, policy frameworks, initiatives and guidelines, to assess gaps and possible needs in addressing training for Open Science (OS) and Responsible Research and Innovation (RRI) practices, for researchers at all career stages. The analysis covers three levels of granularity: European Union (EU), national and institutional policies.

To this end, the document comprises six main parts:

1. Theoretical background part presenting an overview of the approaches the policy mapping builds on;

2. Mapping process section describing the methods and process of generating data for the analysis as well as its limitations;

3. EU level analysis outlining the state-of-the-art of existing EU policies as regards the training on OS and RRI for researchers;

4. National level analysis showing the current state of relevant national policy and legal frameworks in the countries hosting PATTERN pilot institutions;

5. Institutional level analysis describing existing initiatives towards the promotion and application of OS and RRI principles and practices at PATTERN pilot institutions;

6. Results of the mapping section presenting the linkages between different policy levels on the training in OS and RRI practices for researchers as well as gaps and opportunities identified.

Establishing a baseline against which future policy options are compared as a point of departure is a crucial component of the policy making cycle. Moreover, this policy analysis helps to identify a potential for further practical support of training on OS and RRI principles and practices aimed at researchers, at different levels as well as to finetune the content for such training.
Resummations in PDF fits
Creators: name: Bonvini, Marco
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: In this contribution I discuss recent and ongoing progress on the inclusion of resummation effects in the fit of parton distributions.
description: 5 pages. Contribution to the proceedings of DIS 2016
All-mode Renormalization for Tensor Network with Stochastic Noise
Creators: name: Arai, Erika
name: Ohki, Hiroshi
name: Takeda, Shinji
name: Tomii, Masaaki
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: In usual (non-stochastic) tensor network calculations, the truncated singular value decomposition (SVD) is often used for approximating a tensor, and it causes systematic errors. By introducing stochastic noise in the approximation, however, one can avoid such systematic errors at the expense of statistical errors which can be straightforwardly controlled. Therefore in principle, exact results can be obtained even at finite bond dimension up to the statistical errors. A previous study of the unbiased method implemented in tensor renormalization group (TRG) algorithm, however, showed that the statistical errors for physical quantity are not negligible, and furthermore the computational cost is linearly proportional to a system volume. In this paper, we introduce a new way of stochastic noise such that the statistical error is suppressed, and moreover, in order to reduce the computational cost we propose common noise method whose cost is proportional to the logarithm of volume. We find that the method provides better accuracy for the free energy compared with the truncated SVD when applying to TRG for Ising model on square lattice. Although the common noise method introduces systematic error originated from a correlation of noises, we show that the error can be described by a simple functional form in terms of the number of noises, thus the error can be straightforwardly controlled in an actual analysis. We also apply the method to the graph independent local truncation algorithm and show that the accuracy is further improved.
description: 34 pages, 19 figures, 2 tables, version published in Phys.Rev.D
On the Global Well-Posedness of the Einstein-Yang-Mills System
Creators: name: Griggs, Petar
name: Mondal, Puskar
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: In this paper, we present a partial result on the global well-posedness of the Cauchy problem for the Einstein-Yang-Mills system in the constant mean extrinsic curvature spatial harmonic and generalized Coulomb gauges as introduced in [Mondal, arXiv:2112.14273]. We give a small-data global existence theorem for a family of $n+1$ dimensional spacetimes with $n\geq4$, utilizing energy arguments presented in [Andersson and Moncrief, arXiv:0908.0784]. We observe that these energy arguments will fail for $n=3$ due to the conformal invariance of the $3+1$ Yang-Mills equations and present a gauge-covaraiant formulation of the Einstein-Yang-Mills system in $3+1$ dimensions to show that an energy argument cannot be used to prove the global well-posedness result, regardless of the choice of gauge.
description: 33 pages
Detecting non-Markovianity of quantum evolution via spectra of dynamical maps
Creators: name: Chruściński, Dariusz
name: Macchiavello, Chiara
name: Maniscalco, Sabrina
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We provide an analysis on non-Markovian quantum evolution based on the spectral properties of dynamical maps. We introduce the dynamical analog of entanglement witness to detect non-Markovianity and we illustrate its behaviour with several instructive examples. It is shown that for a certain class of dynamical maps the shape of the body of accessible states provides a simple non-Markovianity witness.
description: 5 pages
Hallmarks of non-trivial topology in Josephson junctions based on oxide nanochannels
Creators: name: Maiellaro, Alfonso
name: Settino, Jacopo
name: Guarcello, Claudio
name: Romeo, Francesco
name: Citro, Roberta
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We investigate the topological properties of a Josephson junction obtained by constraining a two-dimensional electron gas at oxide interface to form a quasi-1D conductor. We reveal an anomalous critical current behaviour with a magnetic field applied perpendicular to the Rashba spin-orbit one. We relate the observed critical current enhancement at small magnetic fields with a non-trivial topology, accompanied by Majorana bound states (MBSs) pinned at the edges of the superconducting leads. Signatures of MBSs also include a sawtooth profile in the current-phase relation. Our findings allow to recognize fingerprints of topological superconductivity in non-centrosymmetric materials and confined systems with Rashba spin-orbit interaction, and to explain recent experimental observations for which a microscopic description is still lacking.
description: 10 pages, 8 figures, paper
Exact solution of interacting particle systems related to random matrices
Creators: name: Assiotis, Theodoros
Publisher: name: arXiv
Year: 2022
Subjects: subject: Probability (math.PR)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We consider one-dimensional diffusions, with polynomial drift and diffusion coefficients, so that in particular the motion can be space-inhomogeneous, interacting via one-sided reflections. The prototypical example is the well-known model of Brownian motions with one-sided collisions, also known as Brownian TASEP, which is equivalent to Brownian last passage percolation. We obtain a formula for the finite dimensional distributions of these particle systems, starting from arbitrary initial condition, in terms of a Fredholm determinant of an explicit kernel. As far as we can tell, in the space-inhomogeneous setting and for general initial condition this is the first time such a result has been proven. We moreover consider the model of non-colliding diffusions, again with polynomial drift and diffusion coefficients, which includes the ones associated to all the classical ensembles of random matrices. We prove that starting from arbitrary initial condition the induced point process has determinantal correlation functions in space and time with an explicit correlation kernel. A key ingredient in our general method of exact solution for both models is the application of the backward in time diffusion flow on certain families of polynomials constructed from the initial condition.
description: Revised following referee reports. To appear CMP
Elemental abundances in M31: Individual and Coadded Spectroscopic [Fe/H] and [α/Fe] throughout the M31 Halo with SPLASH
Creators: name: Wojno, J. Leigh
name: Gilbert, Karoline M.
name: Kirby, Evan N.
name: Escala, Ivanna
name: Guhathakurta, Puragra
name: Beaton, Rachael L.
name: Kalirai, Jason
name: Chiba, Masashi
name: Majewski, Steven R.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present spectroscopic chemical abundances of red giant branch (RGB) stars in Andromeda (M31), using medium resolution ($R\sim6000$) spectra obtained via the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) survey. In addition to individual chemical abundances, we coadd low signal-to-noise ratio (S/N) spectra of stars to obtain a high enough to measure average [Fe/H] and [$α$/Fe] abundances. We obtain individual and coadded measurements for [Fe/H] and [$α$/Fe] for M31 halo stars, covering a range of 9--180 kpc in projected radius from the center of M31. With these measurements, we greatly increase the number of outer halo ($R_{\mathrm{proj}} > 50$ kpc) M31 stars with spectroscopic [Fe/H] and [$α$/Fe], adding abundance measurements for 45 individual stars and 33 coadds from a pool of an additional 174 stars. We measure the spectroscopic metallicity ([Fe/H]) gradient, finding a negative radial gradient of $-0.0050\pm0.0003$ for all stars in the halo, consistent with gradient measurements obtained using photometric metallicities. Using the first measurements of [$α$/Fe] for M31 halo stars covering a large range of projected radii, we find a positive gradient ($+0.0026\pm0.0004$) in [$α$/Fe] as a function of projected radius. We also explore the distribution in [Fe/H]--[$α$/Fe] space as a function of projected radius for both individual and coadded measurements in the smooth halo, and compare these measurements to those stars potentially associated with substructure. These spectroscopic abundance distributions highlight the substantial evidence that M31 has had an appreciably different formation and merger history compared to our own Galaxy.
description: Submitted to ApJ