cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Fermi isospectrality of discrete periodic Schrödinger operators with separable potentials on $\mathbb{Z}^2$
Creators: name: Liu, Wencai
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mathematical Physics (math-ph)
subject: Algebraic Geometry (math.AG)
subject: Complex Variables (math.CV)
subject: Spectral Theory (math.SP)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: Let $Γ=q_1\mathbb{Z}\oplus q_2 \mathbb{Z} $ with $q_1\in \mathbb{Z}_+$ and $q_2\in\mathbb{Z}_+$. Let $Δ+X$ be the discrete periodic Schrödinger operator on $\mathbb{Z}^2$, where $Δ$ is the discrete Laplacian and $X:\mathbb{Z}^2\to \mathbb{C}$ is $Γ$-periodic. In this paper, we develop tools from complex analysis to study the isospectrality of discrete periodic Schrödinger operators. We prove that if two $Γ$-periodic potentials $X$ and $Y$ are Fermi isospectral and both $X=X_1\oplus X_2$ and $Y= Y_1\oplus Y_2$ are separable functions, then, up to a constant, one dimensional potentials $X_j$ and $Y_j$ are Floquet isospectral, $j=1,2$. This allows us to prove that for any non-constant separable real-valued $Γ$-periodic potential, the Fermi variety $F_λ(V)/\mathbb{Z}^2$ is irreducible for any $λ\in \mathbb{C}$, which partially confirms a conjecture of Gieseker, Knörrer and Trubowitz in the early 1990s.
A dynamical mass estimator for high z galaxies based on spectroastrometry
Creators: name: Gnerucci, A.
name: Marconi, A.
name: Cresci, G.
name: Maiolino, R.
name: Mannucci, F.
name: Schreiber, N. M. Forster
name: Davies, R.
name: Shapiro, K.
name: Hicks, E. K. S.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Galaxy dynamical masses are important physical quantities to constrain galaxy evolutionary models, especially at high redshifts. However, at z~2 the limited signal to noise ratio and spatial resolution of the data usually do not allow spatially resolved kinematical modeling and very often only virial masses can be estimated from line widths. But even such estimates require a good knowledge of galaxy size, which may be smaller than the spatial resolution. Spectroastrometry is a technique which combines spatial and spectral resolution to probe spatial scales significantly smaller than the spatial resolution of the observations. Here we apply it to the case of high-z galaxies and present a method based on spectroastrometry to estimate dynamical masses of high z galaxies, which overcomes the problem of size determination with poor spatial resolution. We construct and calibrate a "spectroastrometric" virial mass estimator, modifying the "classical" virial mass formula. We apply our method to the [O III] or Hα emission line detected in z~2-3 galaxies from AMAZE, LSD and SINS samples and we compare the spectroastrometric estimator with dynamical mass values resulting from full spatially resolved kinematical modeling. The spectroastrometric estimator is found to be a good approximation of dynamical masses, presenting a linear relation with a residual dispersion of only 0.15 dex. This is a big improvement compared to the "classical" virial mass estimator which has a non linear relation and much larger dispersion (0.47 dex) compared to dynamical masses. By applying our calibrated estimator to 16 galaxies from the AMAZE and LSD samples, we obtain masses in the ~10^7-10^10 M\odot range extending the mass range attainable with dynamical modeling.
Spider Ion Source and Extraction Power Supplies -- An update of the design after four years of operation
Creators: name: Shepherd, A.
name: Bigi, M.
name: Casagrande, R.
name: Dan, M.
name: Maistrello, A.
name: Sartori, E.
name: Serianni, G.
name: Decamps, H.
name: Zanotto, L.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: SPIDER, the ion source prototype for ITER neutral beam injectors, has been in operation since 2018. The experiment includes a system of Ion Source and Extraction Power Supplies (ISEPS), whose design dates back to 2011. Since then the experience gained has led to substantial changes, the most dramatic modification being the complete replacement of the radiofrequency power supply, described elsewhere. This contribution details operating experience and calculations that have led to defining new requirements for a specific subset of power supplies, the bias power supplies. The bias power supplies perform the function of filtering out electrons extracted together with the negative ions and in the original 2011 ISEPS design are single quadrant resonant converters. For the two bias power supplies, the picture resulting from the review described in the paper is a substantial redesign, with the ability to operate in four quadrants and a twofold increase of the rated output voltage the most significant new specifications.
Luigi Bernabò Brea, Menandro e il teatro greco nelle terracotte liparesi
Creators: name: Besques, Simone
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Luigi Bernabò Brea, Menandro e il teatro greco nelle terracotte liparesi. SAGEP S.p.A. éd., Gênes 1981. 328 pages, 475 illustrations, 43 planches couleur.
description: Bonner Jahrbücher, Bd. 185.1985: Bonner Jahrbücher
Statistical parameters of femtosecond laser pulse post-filament propagation on 65m air path with localized optical turbulence
Creators: name: Apeksimov, Dmitry V.
name: Bulygin, Andrey V.
name: Geints, Yury E.
name: Kabanov, Andrey M.
name: Petrov, Aleksey V.
name: Khoroshaeva, Elena E.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: High-power femtosecond laser radiation propagates nonlinearly in air exhibiting pulse self-focusing and strong multiphoton medium ionization, which leads to the spatial fragmentation of laser pulse into highly-localized light channels usually called the filaments. The filaments are characterized by high optical intensity, reduced (even zero) angular spreading and can contain laser plasma or be plasmaless (postfilaments). The presence of optical turbulence on the propagation path dramatically changes pulse filamentation dynamics and in some cases causes pulse fragmentation enhancement and collapse arrest. For the first time to our knowledge, we experimentally and theoretically investigate the transverse profile of Ti:sapphire femtosecond laser radiation nonlinearly propagating a 65 m air path to the region of postfilament evolution after passing through an artificial localized air turbulence. We show that when a turbulent layer is placed before the filamentation region, the average number of high-intensive local fluence maxima ("hot points") in pulse profile as well as their sizes grow as the turbulence strength increases, and then saturates at some levels. On the contrary, the deposition of a turbulent screen within the filamentation region has almost no effect on both the number and the average diameter of the postfilaments.
Social Sustainability Challenges and the Role of Middle Managers
Case of the Ready-Made Garment Industry in Bangladesh
Creators: name: Draganić, Aleksandra
name: Arefin, Nazmul
Publisher: name: Universität Kassel
Year: 2021
Subjects: subject: female-friendly work environment
subject: social sustainability
subject: long working hours
subject: occupational health and safety
subject: transnational industry
subject: mid-level manager
subject: sub-contracting company
subject: 300
subject: Bangladesch
subject: Konfektion
subject: Bekleidungsindustrie
subject: Nachhaltigkeit
subject: Arbeitsbedingungen
subject: Mittleres Management

description: Research and the print of this working paper was funded by the German Corporation for International Cooperation (GIZ)
Target of opportunity observations of flaring blazars with VERITAS
Creators: name: Errando, M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: VERITAS is an array of four imaging atmospheric Cherenkov telescopes that observes gamma-ray sources in the very high energy range (VHE, E>100 GeV). A large fraction of the known gamma-ray sources are of extragalactic origin and belong to the blazar class: active galactic nuclei with relativistic jets pointing along the line of sight. Gamma-ray emission from blazars is typically variable. Part of the VERITAS observation program is devoted to follow-up triggers on flaring blazars, initiated by observations at other wavelengths. We will present those target of opportunity observations based on optical and GeV (Fermi-LAT) alerts performed with VERITAS during the past 2 seasons, and discuss the results in a multiwavelength context.
description: 4 pages, to appear in proceedings of the 32nd ICRC, Beijing, China
New variable sources revealed by DECam toward the LMC: the first 15 deg2
Creators: name: Franco, A.
name: Nucita, A. A.
name: De Paolis, F.
name: Strafella, F.
name: Sacquegna, S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The Dark Energy Camera (DECam) is a sensitive, wide field instrument mounted at the prime focus of the 4 m V. Blanco Telescope in Chile. Beside its main objectives, i.e. understanding the growth and evolution of structures in the Universe, the camera offers the opportunity to observe a 3 deg2 field of view in one single pointing and, with an adequate cadence, to identify the variable sources contained. In this paper, we present the result of a DECam observational campaign toward the LMC and give a catalogue of the observed variable sources. We considered all the available DECam observations of the LMC, acquired during 32 nights over a period of two years (from February 2018 to January 2020), and set up a specific pipeline for detecting and characterizing variable sources in the observed fields. Here, we report on the first 15 deg2 in and around the LMC as observed by DECam, testing the capabilities of our pipeline. Since many of the observed fields cover a rather crowded region of the sky, we adopted the ISIS subtraction package which, even in these conditions, can detect variables at a very low signal to noise ratio. All the potentially identified variable sources were then analyzed and each light curve tested for periodicity by using the Lomb-Scargle and Schwarzenberg-Czerny algorithms. Furthermore, we classified the identified sources by using the UPSILoN neural network. This analysis allowed us to find 70 981 variable stars, 1266 of which were previously unknown. We estimated the period of the variables and compared it with the available values in the catalogues. Moreover, for the 1266 newly detected objects, an attempted classification based on light curve analysis is presented.
description: 11 pages, 7 figures
SOFIA observations of CO(12-11) emission along the L1157 bipolar outflow
Creators: name: Eislöffel, Jochen
name: Nisini, Brunella
name: Güsten, Rolf
name: Wiesemeyer, Helmut
name: Gusdorf, Antoine
Publisher: name: arXiv
Year: 2012
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Carbon monoxide is an excellent tracer of the physical conditions of gas in molecular outflows from young stars. To understand the outflow mechanism we need to investigate the origin of the molecular emission and the structure and interaction of the outflowing molecular gas. Deriving the physical parameters of the gas will help us to trace and understand the various gas components in the flow. We observed CO(12-11) line emission at various positions along the L1157 bipolar outflow with GREAT aboard SOFIA. Comparing these new data with CO(2-1), we find basically constant line ratios along the outflow and even at the position of the source. These line ratios lead us to estimates of 10^5 to 10^6 cm^-3 for the gas density and 60 to 100 K for the gas temperature of the outflowing gas. The constrained density and temperature values indicate that we are mostly tracing a low-velocity gas component everywhere along the outflow, which is intermediate between the already known cold gas component, which gets entrained into the flow, and the hot gas, which gets shocked in the outflow.
Local Neumann semitransparent layers: resummation, pair production and duality
Creators: name: Ahmadiniaz, N.
name: Franchino-Viñas, S. A.
name: Manzo, L.
name: Mazzitelli, F. D.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider local semitransparent Neumann boundary conditions for a quantum scalar field as imposed by a quadratic coupling to a source localized on a flat codimension-one surface. Upon a proper regularization to give meaning to the interaction, we interpret the effective action as a theory in a first-quantized phase space. We compute the relevant heat-kernel to all order in a homogeneous background and to quadratic order in perturbations, giving a closed expression for the corresponding effective action in $D=4$. In the dynamical case, we analyze the pair production caused by a harmonic perturbation and by a Sauter pulse. Notably, we prove the existence of a strong/weak duality that links this Neumann field theory to the analogue Dirichlet one.
description: 32 pages, 2 figures
Simulations of Noise in Phase-Separated Transition-Edge Sensors for SuperCDMS
Creators: name: Anderson, A. J.
name: Leman, S. W.
name: Pyle, M.
name: Figueroa-Feliciano, E.
name: McCarthy, K.
name: Doughty, T.
name: Cherry, M.
name: Young, B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We briefly review a simple model of superconducting-normal phase-separation in transition-edge sensors in the SuperCDMS experiment. After discussing some design considerations relevant to the TES in the detectors, we study noise sources in both the phase-separated and phase-uniform cases. Such simulations are valuable for optimizing the critical temperature and TES length of future SuperCDMS detectors.
description: Low Temperature Detector 14 conference proceedings to be published in the Journal of Low Temperature Physics, 6 pages, 4 figures
Very high energy follow-up observations of GRBs detected by Fermi and Swift
Creators: name: Aune, Taylor
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In many theoretical models of gamma-ray bursts (GRBs) and their afterglows, the emission of photons above 100 GeV is predicted. The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope has detected delayed, high-energy emission (up to 90 GeV in the burst rest-frame) from several GRBs and no evidence of a high-energy spectral cutoff during the early afterglow phase of the burst has been found. Presented here are the results of follow-up observations with VERITAS, a ground-based telescope array sensitive to gamma-rays above 100 GeV, of GRBs detected by the Fermi and Swift satellites. These observations have not yielded a conclusive detection and the upper limits on very high energy (VHE, E>100 GeV) gamma-ray flux obtained from these observations are among the most constraining to date.
description: 4 pages, 2 figures, Proceeding of the 32nd International Cosmic Ray Conference (Beijing 2011)
Chemical evolution in ices on drifting, planet-forming pebbles
Creators: name: Eistrup, Christian
name: Henning, Thomas
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Planets and their atmospheres are built from gas and solid material in protoplanetary disks. Recent results suggest that solid material like pebbles may contribute significantly to building up planetary atmospheres. In order to link observed exoplanet atmospheres and their compositions to their formation histories, it is important to understand how icy pebbles may change their composition when they drift radially inwards in disks. Our goal is to model the compositional evolution of ices on pebbles as they drift in disks, and track how their chemical evolution en-route changes the ice composition relative to the ice composition of the pebbles in the region where they grew from micron-sized grains. A state-of-the-art chemical kinetics code is utilised for modelling chemical evolution. This code accounts for the time-evolving sizes of the solids that drift. Chemical evolution is modelled locally for 0.1Myr at two starting radii, with the micron-sized solids growing into pebbles simultaneously. The pebbles and local gas, isolated as a parcel, is then exposed to changing physical conditions, intended to mimic the pebbles drifting inwards in the disk midplane, moving to 1 AU on three different timescales. A modelling simplification is that the pebbles are \emph{not} moved through, and exposed to new gas, but stay in the same chemical gas surroundings in all models. For ice species with initial abundances relative to hydrogen of $>10^{-5}$, such as H$_{2}$O, CO$_{2}$, CH$_{3}$OH and NH$_{3}$, the abundances change by less than 20% for both radii of origin, and for the two smaller drift timescales (10kyr and 100kyr). For less abundant ice species, and the longest drift timescale (1Myr), the changes are larger. Pebble drift chemistry generally increases the ice abundances of CO$_{2}$, HCN and SO, at the expense of decreasing abundances of other volatile molecules.
description: Accepted by Astronomy & Astrophysics. 11 pages
Page Entropy of Proton System in Deep-Inelastic-Scattering at Small-$x$
Creators: name: Kou, Wei
name: Wang, Xiaopeng
name: Chen, Xurong
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The partons model reveals the dynamical structure of nucleons (protons and neutrons). Studies related to thermodynamic quantities of nucleons are interesting and topical questions. In this work, for the first time we apply Page's theory of the studies of black hole to investigate the entropy of proton system. Inspired by the quantum entanglement entropy in black hole information theories, we establish the proton entanglement with the similar way. Based our calculations, the proton entanglement entropy has the approximate form $S = \ln m -1/2$, where $m$ represents the partons density of proton (mainly gluon and sea quark contributions) at small Bjorken $x$. Our calculations using Page's theory are well in agreement with the recent DIS measurements from H1 collaboration.
description: 6 pages, 2 figures, Accepted by PRD
Phononic gaps in the charged incommensurate planes of Sr14Cu24O41
Creators: name: Thorsmolle, V. K.
name: Homes, C. C.
name: Gozar, A.
name: Blumberg, G.
name: van Mechelen, J. L. M.
name: Kuzmenko, A. B.
name: Vanishri, S.
name: Marin, C.
name: Ronnow, H. M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The terahertz (THz) excitations in the quantum spin-ladder system Sr14Cu24O41 have been determined along the c-axis using THz time-domain, Raman and infrared spectroscopy. Low-frequency infrared and Raman active modes are observed above and below the charge-ordering temperature T_{co} ~ 200 K over a narrow interval of 1 - 2 meV . A new infrared mode around 1 meV develops below ~ 100 K. The temperature dependence of these modes shows that they are coupled to the charge- and spin-density-wave correlations in this system. These low-energy features are conjectured to originate in the gapped sliding-motion of the chain and ladder sub-systems, which are both incommensurate and charged.
description: Accepted for publication in Physical Review Letters
title: Rigorous Error Bounds for Finite Dimensional Linear Programming Problems
title: Rigorose Fehlerschranken für endlich-dimensionale lineare Programme
titleType: AlternativeTitle
Creators: name: Keil, Christian
Publisher: name: TUHH Universitätsbibliothek
Year: 2009
Subjects: subject: Rigorose Schranke, Softwarepaket
subject: linear programming
subject: rigorous error bounds
subject: interval arithmetic
subject: software
subject: Fehlerschranke
subject: Intervallalgebra
subject: Lineare Optimierung
classificationCode: 90C05
subject: Linear programming

description: Die Dissertation behandelt die Theorie, Implementierung und Anwendung rigoroser Fehlerschranken für endlich-dimensionale lineare Programme. Trotz der gut verstandenen Theorie und zahlreicher Anwendungen liefern kommerzielle Softwarepakete häufig falsche Resultate für diese Probleme. Im Gegensatz dazu liefern Verifikationsmethoden nachweislich korrekte Ergebnisse. Die Arbeit präsentiert Theoreme, die solche Schranken liefern, begleitet von einer Konvergenzanalyse und Verallgemeinerungen. Das Softwarepaket Lurupa wird beschrieben, welches die rigorosen Schranken als eigenständiges Paket, als Bibliothek und von MATLAB aus zur Verfügung stellt. Ausführliche numerische Experimente und ein Vergleich mit anderen Softwarepaketen werden präsentiert. Diese demonstrieren die Notwendigkeit die spezielle Struktur eines Problems auszunutzen, um schnelle und zuverlässige Ergebnisse zu erhalten.
description: This dissertation treats the theory, implementation, and application of rigorous error bounds in the context of finite dimensional linear programming problems. Despite the theory of linear programming that is well understood and its numerous applications, commercial solvers frequently produce erroneous results for these problems. In contrast, verification methods yield solutions proved to be correct. The thesis presents theorems that yield rigorous error bounds, a convergence analysis, and generalizations. The software package Lurupa is described, which offers the rigorous error bounds as a standalone software, a library, and from MATLAB. Extensive numerical experiments and a comparison with other software packages are presented. They demonstrate that exploiting the special structure of a problem is necessary when aiming for fast and reliable results.
Observational Hubble parameter data constraints on the interactive model of $f(T)$ gravity with particle creation
Creators: name: Ganjizadeh, S.
name: Amani, Alireza
name: Ramzanpour, M. A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, we consider an open system from the thermodynamic perspective for an adiabatic FRW universe model in which particle creation occurs within the system. In that case, the modified continuity equation is obtained and then we correspond it to the continuity equation of $f(T)$ gravity. So, we take $f(T)$ gravity with the viscous fluid in flat-FRW metric, in which $T$ is the torsion scalar. We consider the contents of the universe to be dark matter and dark energy and consider an interaction term between them. The interesting point of this study is that we make equivalent the modified continuity equation resulting from the particle creation with the matter continuity equation resulting from $f(T)$ gravity. The result of this evaluation creates a relationship between the number of particles and the scale factor. In what follows, we write the corresponding cosmological parameters in terms of the number of particles and also reconstruct the number of particles in terms of the redshift parameter, then We parameterize the Hubble parameter derived from power-law cosmology with 51 data from the Hubble observational parameter. Next, we plot the corresponding cosmological parameters for the dark energy in terms of the redshift to investigate the accelerated expansion of the universe. In addition, by using the sound speed parameter, we discuss the stability analysis and instability analysis of the present model in different eras of the universe. Finally, we plot the density parameter values for dark energy and dark matter in terms of the redshift parameter.
description: 19 pages, 7 figures, Accepted in Chinese Physics C
Low-temperature specific heat for ferromagnetic and antiferromagnetic orders in CaRu1-xMnxO3
Creators: name: Yokoyama, M.
name: Nakano, S.
name: Someya, S.
name: Nakada, T.
name: Wada, N.
name: Kawanaka, H.
name: Bando, H.
name: Tenya, K.
name: Kondo, A.
name: Kindo, K.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Low-temperature specific heat of CaRu1-xMnxO3 was measured to clarify the role of d electrons in ferromagnetic and antiferromagnetic orders observed above x=0.2. Specific heat divided by temperature C_p/T is found to roughly follow a T^2 function, and relatively large magnitudes of electronic specific heat coefficient gamma were obtained in wide x range. In particular, gamma is unchanged from the value at x=0 (84 mJ/K^2 mol) in the paramagnetic state for x<=0.1, but linearly reduced with increasing x above x= 0.2. These features of gamma strongly suggest that itinerant d electrons are tightly coupled with the evolution of magnetic orders in small and intermediate Mn concentrations.
description: 4 pages, 2 figures, to be published in J. Phys.: Conf. Ser. (SCES 2011, Cambridge, UK)
Super-Resonant Dark Matter
Creators: name: Csáki, Csaba
name: Gomes, Andrew
name: Hochberg, Yonit
name: Kuflik, Eric
name: Langhoff, Kevin
name: Murayama, Hitoshi
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We introduce Super-Resonant Dark Matter, a model of self-interacting dark matter based on the low energy effective theory of supersymmetric QCD. The structure of the theory ensures a resonant enhancement of the self-interactions of the low energy mesons, since their mass ratio is set by the number of colors and flavors. The velocity dependence of the resonantly enhanced self-interactions allows such theories to accommodate puzzles in small scale structure that arise from dark matter halos of different sizes. The dark matter mass is then predicted to be around 3-4 MeV, with its abundance set by freeze-in via a kinetically mixed dark photon.
Silicon sensors with resistive read-out: Machine Learning techniques for ultimate spatial resolution
Creators: name: Tornago, Marta
name: Giobergia, Flavio
name: Menzio, Luca
name: Siviero, Federico
name: Arcidiacono, Roberta
name: Cartiglia, Nicolò
name: Costa, Marco
name: Ferrero, Marco
name: Gioachin, Giulia
name: Mandurrino, Marco
name: Sola, Valentina
Publisher: name: arXiv
Year: 2022
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Resistive AC-coupled Silicon Detectors (RSDs) are based on the Low Gain Avalanche Diode (LGAD) technology, characterized by a continuous gain layer, and by the innovative introduction of resistive read-out. Thanks to a novel electrode design aimed at maximizing signal sharing, RSD2, the second RSD production by Fondazione Bruno Kessler (FBK), achieves a position resolution on the whole pixel surface of about 8 $μm$ for 200-$μm$ pitch. RSD2 arrays have been tested using a Transient Current Technique setup equipped with a 16-channel digitizer, and results on spatial resolution have been obtained with machine learning algorithms.
description: 2 pages, 2 figure
Transient chaos analysis of string scattering
Creators: name: Hashimoto, Koji
name: Matsuo, Yoshinori
name: Yoda, Takuya
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It has long been thought that a highly excited string can be regarded as a black hole: the correspondence principle between strings and a black hole, while recent studies found that black holes are characterized by chaos. This suggests that highly excited strings are the source of the black hole chaoticity. We study the chaoticity of a string amplitude where a tachyon is scattered by a highly excited string. Our strategy to extract the chaos in the amplitude is a generalization of the transient chaos analysis for classical scattering. We look for the fractal structure in the plots of incoming/outgoing scattering angles, where the outgoing angle is defined as the maximum pole of the amplitude. Within our strategy, we could not identify any fractal structure in the scattering data. We also discuss other possible setups and strategies to extract the chaos, hoping that our present work serves as a step toward the formulation of chaos in string scattering amplitudes.
description: 26 pages, 6 figures
Factorization number and subgroup commutativity degree via spectral invariants
Creators: name: Muhie, Seid Kassaw
name: Otera, Daniele Ettore
name: Russo, Francesco G.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Combinatorics (math.CO)
subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 20D60, 05C25, 05C07, 05C15, 20K27

description: The factorization number $F_2(G)$ of a finite group $G$ is the number of all possible factorizations of $G=HK$ as product of its subgroups $H$ and $K$, while the subgroup commutativity degree $\mathrm{sd}(G)$ of $G$ is the probability of finding two commuting subgroups in $G$ at random. It is known that $\mathrm{sd}(G)$ can be expressed in terms of $F_2(G)$. Denoting by $\mathrm{L}(G)$ the subgroups lattice of $G$, the non--permutability graph of subgroups $Γ_{\mathrm{L}(G)}$ of $G$ is the graph with vertices in $\mathrm{L}(G) \setminus \mathfrak{C}_{\mathrm{L}(G)}(\mathrm{L}(G))$, where $\mathfrak{C}_{\mathrm{L}(G)}(\mathrm{L}(G))$ is the smallest sublattice of $\mathrm{L}(G)$ containing all permutable subgroups of $G$, and edges obtained by joining two vertices $X,Y$ such that $XY\neq YX$. The spectral properties of $Γ_{\mathrm{L}(G)}$ have been recently investigated in connection with $F_2(G)$ and $\mathrm{sd}(G)$. Here we show a new combinatorial formula, which allows us to express $F_2(G)$, and so $\mathrm{sd}(G)$, in terms of adjacency and Laplacian matrices of $Γ_{\mathrm{L}(G)}$.
description: 12 pages, 3 figures, preliminary version
Finite temperature dynamics in gapped 1D models in the sine-Gordon family
Creators: name: Kormos, Márton
name: Vörös, Dániel
name: Zaránd, Gergely
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The sine-Gordon model appears as the low-energy effective field theory of various one-dimensional gapped quantum systems. Here we investigate the dynamics of generic, non-integrable systems belonging to the sine-Gordon family at finite temperature within the semiclassical approach. Focusing on time scales where the effect of nontrivial quasiparticle scatterings becomes relevant, we obtain universal results for the long-time behavior of dynamical correlation functions. We find that correlation functions of vertex operators behave neither ballistically nor diffusively but follow a stretched exponential decay in time. We also study the full counting statistics of the topological current and find that distribution of the transferred charge is non-Gaussian with its cumulants scaling non-uniformly in time.
Nuclear physics with a medium-energy Electron-Ion Collider
Creators: name: Accardi, A.
name: Guzey, V.
name: Prokudin, A.
name: Weiss, C.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: A polarized ep/eA collider (Electron-Ion Collider, or EIC) with variable center-of-mass energy sqrt(s) ~ 20-70 GeV and a luminosity ~ 10^{34} cm^{-2} s^{-1} would be uniquely suited to address several outstanding questions of Quantum Chromodynamics (QCD) and the microscopic structure of hadrons and nuclei: (i) the three-dimensional structure of the nucleon in QCD (sea quark and gluon spatial distributions, orbital motion, polarization, correlations); (ii) the fundamental color fields in nuclei (nuclear parton densities, shadowing, coherence effects, color transparency); (iii) the conversion of color charge to hadrons (fragmentation, parton propagation through matter, in-medium jets). We briefly review the conceptual aspects of these questions and the measurements that would address them, emphasizing the qualitatively new information that could be obtained with the collider. Such a medium-energy EIC could be realized at Jefferson Lab after the 12 GeV Upgrade (MEIC), or at Brookhaven National Lab as the low-energy stage of eRHIC.
description: 9 pages, 5 figures. Mini-review compiled in preparation for the MEIC Conceptual Design Report, Jefferson Lab (2011)
Single- and two-particle finite size effects in interacting lattice systems
Creators: name: Iskakov, Sergei
name: Terletska, Hanna
name: Gull, Emanuel
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Simulations of extended quantum systems are typically performed by extrapolating results of a sequence of finite-system-size simulations to the thermodynamic limit. In the quantum Monte Carlo community, twist-averaging was pioneered as an efficient strategy to eliminate one-body finite size effects. In the dynamical mean field community, cluster generalizations of the dynamical mean field theory were formulated to study systems with non-local correlations. In this work, we put the twist-averaging and the dynamical cluster approximation variant of the dynamical mean field theory onto equal footing, discuss commonalities and differences, and compare results from both techniques to the standard periodic boundary technique. At the example of Hubbard-type models with local, short-range and Yukawa-like longer range interactions we show that all methods converge to the same limit, but that the convergence speed differs in practice. We show that embedding theories are an effective tool for managing both one-body and two-body finite size effects, in particular if interactions are averaged over twist angles.
description: 12 pages, 10 figures
General Theory for the Ferroelectric Polarization Induced by Spin-Spiral Order
Creators: name: Xiang, H. J.
name: Kan, E. J.
name: Zhang, Y.
name: Whangbo, M. -H.
name: Gong, X. G.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The ferroelectric polarization of triangular-lattice antiferromagnets induced by helical spin-spiral order is not explained by any existing model of magnetic-order-driven ferroelectricity. We resolve this problem by developing a general theory for the ferroelectric polarization induced by spin-spiral order and then by evaluating the coefficients needed to specify the general theory on the basis of density functional calculations. Our theory correctly describes the ferroelectricity of triangular-lattice antiferromagnets driven by helical spin-spiral order, and incorporates known models of magnetic-order-driven ferroelectricity as special cases.
description: Accepted for publication in Phys. Rev. Lett
D1.4 Applicability of the Ethics guidelines for trustworthy AI to the COLLABS approach
Creators: name: Puccetti, Armand
name: Srdan Srkbic
name: Natasa Vujnovic Sedlar
name: Wimmer, Martin
name: Prabhakaran Kasinathan
name: Disez, Erwan Le
name: Davide Martintoni,
name: Senni, Valerio
name: Moed, Erwin
name: Alexopoulos, Dimitris
name: Alzahraa Alhaddad
Publisher: name: Zenodo
Year: 2021
Subjects: AI, Ethics

description: This document was requested by the EC further to the deliverables promised by the project in its technical annex. Therefore, it is an assessment of the ethical use of AI technologies within the COLLABS project. The document contains a questionnaire filled in by project partners involved in AI activities, either as AI tools producers or as AI tools users.
description: Beware that this document does not aim to be complete in any sense nor give any definite answers to all questions of the questionnaire, as the project is in progress and much work remains to be done. Thus, the project gives the best of its knowledge about the topic of ethical use of AI techniques within COLLABS.
Contribution of polycyclic aromatic hydrocarbon ionization to neutral gas heating in galaxies: model versus observations
Creators: name: Berné, O.
name: Foschino, S.
name: Jalabert, F.
name: Joblin, C.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: [Abridged] The ionization of polycyclic aromatic hydrocarbons (PAHs), by ultraviolet (UV) photons from massive stars is expected to account for a large fraction of the heating of neutral gas in galaxies. Evaluation of this proposal, however, has been limited by our ability to directly compare observational diagnostics to the results of a molecular model describing PAH ionization. The objective of this article is to take advantage of the most recent values of molecular parameters derived from laboratory experiments and quantum chemical calculations on PAHs and provide a detailed comparison between modeled values and observational diagnostics for the PAH charge state and the heating efficiency for PAHs. Despite the use of a simple analytical model, we obtain a good agreement between model results and observational diagnostics over a wide range of radiation fields and physical conditions, in environments such as star-forming regions, galaxies, and protoplanetary disks. In addition, we found that the modeled photoelectric heating rates by PAHs are close to the observed cooling rates given by the gas emission. These results show that PAH ionization is the main source of neutral gas heating in these environments. The results of our photoelectric heating model by PAHs can thus be used to assess the contribution of UV radiative heating in galaxies (vs shocks, for instance). We provide the empirical formulas fitted to the model results, and the full python code itself, to calculate the heating rates and heating efficiencies for PAHs.
description: Accepted for publication in Astronomy and Astrophysics
title: Optimisation of fatigue behaviour of Ti-6Al-4V alloy components fabricated by metal injection moulding
title: Optimierung des Ermüdungsverhaltens mittels MIM hergestellter Bauteile aus TiAL6V4
titleType: AlternativeTitle
Creators: name: Ferri, Orley Milagres
Publisher: name: TUHH Universitätsbibliothek
Year: 2010
Subjects: subject: HCF-Verhalten
subject: Metallpulver-Spritzgießen
subject: Oberflächenqualität
subject: Porosität
subject: inhärenter Defekt
subject: high cycle fatigue behaviour
subject: metal injection moulding MIM
subject: surface quality
subject: porosity
subject: Spritzgießen
subject: Ermüdung bei hohen Lastspielzahlen
subject: Metallbauteil

description: In der vorliegenden Arbeit wurde das HCF-Verhalten von Bauteilen aus Ti-6Al-4V, die mittels Metallpulver-Spritzgießens (Metal Injection Moulding MIM) hergestellt wurden, detailliert untersucht. Die Experimente wurden mit dem Ziel durchgeführt, den Einfluss von kritischen Eigenschaften wie Oberflächenqualität, Porosität und anderen mikrostrukturellen Merkmalen auf das Ermüdungsverhalten zu bestimmen. Auf Basis der Ergebnisse dieser Untersuchung wurde eine Legierung entworfen, die eine Mikrostruktur aufweist, die die grundsätzliche Verschlechterung der HCF Eigenschaften, die aus den der MIM Herstellung inhärenten Defekten resultiert, minimiert.
description: In the present work, the high cycle fatigue behaviour of Ti-6Al-4V components fabricated by metal injection moulding (MIM) was investigated in detail. Experiments were conducted in an attempt to determine the influence of critical features such as surface quality, porosity and microstructural features on the fatigue behaviour. Based on the results obtained in this investigation, an alloy has been designed with the microstructure features required to minimise the degradation of the high cycle fatigue behaviour resulting from the presence of inherent MIM processing defects.
Normalizing Flow-based Neural Process for Few-Shot Knowledge Graph Completion
Creators: name: Luo, Linhao
name: Li, Yuan-Fang
name: Haffari, Gholamreza
name: Pan, Shirui
Publisher: name: arXiv
Year: 2023
Subjects: subject: Information Retrieval (cs.IR)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Knowledge graphs (KGs), as a structured form of knowledge representation, have been widely applied in the real world. Recently, few-shot knowledge graph completion (FKGC), which aims to predict missing facts for unseen relations with few-shot associated facts, has attracted increasing attention from practitioners and researchers. However, existing FKGC methods are based on metric learning or meta-learning, which often suffer from the out-of-distribution and overfitting problems. Meanwhile, they are incompetent at estimating uncertainties in predictions, which is critically important as model predictions could be very unreliable in few-shot settings. Furthermore, most of them cannot handle complex relations and ignore path information in KGs, which largely limits their performance. In this paper, we propose a normalizing flow-based neural process for few-shot knowledge graph completion (NP-FKGC). Specifically, we unify normalizing flows and neural processes to model a complex distribution of KG completion functions. This offers a novel way to predict facts for few-shot relations while estimating the uncertainty. Then, we propose a stochastic ManifoldE decoder to incorporate the neural process and handle complex relations in few-shot settings. To further improve performance, we introduce an attentive relation path-based graph neural network to capture path information in KGs. Extensive experiments on three public datasets demonstrate that our method significantly outperforms the existing FKGC methods and achieves state-of-the-art performance. Code is available at https://github.com/RManLuo/NP-FKGC.git.
description: Accepted by SIGIR2023
Performance Evaluation of H.264 AVC Using CABAC Entropy Coding For Compound Image Compression
Creators: name: Kumar, Dr.P.S.Jagadeesh
Publisher: name: figshare
Year: 2019
Subjects: subject: Artificial Intelligence and Image Processing
subject: FOS: Computer and information sciences
subject: Theoretical Computer Science
subject: Applied Computer Science

description: The proposed paper aims in evaluating the performance of H.264/MPEG-4 part 10, “Advanced Video Coding” standard using CABAC entropy coding for compression of different types of images. The performance evaluation is based on the metrics such as compression ratio and PSNR at different bits per pixel (Bpp). The different types of images used to test the performance of the proposed system are compound image, text image, natural image and computer generated image. The proposed system has been simulated in matlab
simulink environment. It is observed that the H.264AVC using CABAC entropy coding is very efficient in compressing compound images with higher compression ratio and PSNR compared to other types of images at high bitrates.
Analytic two-loop amplitudes for $tW$ production: leading color and light fermion-loop contributions
Creators: name: Chen, Long-Bin
name: Dong, Liang
name: Li, Hai Tao
name: Li, Zhao
name: Wang, Jian
name: Wang, Yefan
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present the analytical results of the two-loop amplitudes for hadronic $tW$ production, focusing on the leading color and light fermion-loop contributions. The calculation of the two-loop integrals is performed using the method of canonical differential equations. The results have been expressed in terms of multiple polylogarithms and checked by comparing the infra-red divergences with the predictions from anomalous dimensions. Combined with the one-loop squared amplitudes we have computed previously, we obtain the hard function relevant to a NNLO Monte Carlo calculation. We find that the hard function varies slowly in the region with small top quark velocity but increases dramatically in the region with very large top quark velocity. After phase space integration, the leading color hard function gives an about $5.4\%$ correction to the leading order cross section, while the light fermion loop contributes about $-1.4\%$.
description: 20 pages, 8 figures
Smoothness of holonomy covers for singular foliations and essential isotropy
Creators: name: Androulidakis, Iakovos
name: Zambon, Marco
Publisher: name: arXiv
Year: 2011
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 57R30, 58H05, 57R55

description: Given a singular foliation, we attach an "essential isotropy" group to each of its leaves, and show that its discreteness is the integrability obstruction of a natural Lie algebroid over the leaf. We show that a condition ensuring discreteness is the local surjectivity of a transversal exponential map associated with the maximal ideal of vector fields prescribed to be tangent to the foliation. The essential isotropy group is also shown to control the smoothness of the holonomy cover of the leaf (the associated fiber of the holonomy groupoid), as well as the {smoothness} of the associated isotropy group. Namely, the (topological) closeness of the essential isotropy group is a necessary and sufficient condition for the holonomy cover to be a smooth (finite-dimensional) manifold and the isotropy group to be a Lie group. These results are useful towards understanding the normal form of a singular foliation around a compact leaf. At the end of this article we briefly outline work of ours on this normal form, to be presented in a subsequent paper.
The $S=1$ dimer system K$_2$Ni(MoO$_4$)$_2$: a candidate for magnon Bose-Einstein condensation
Creators: name: Lenz, B.
name: Koteswararao, B.
name: Biermann, S.
name: Khuntia, P.
name: Baenitz, M.
name: Panda, S. K.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Dimerized quantum magnets provide a unique possibility to investigate Bose-Einstein condensation of magnetic excitations in crystalline systems at low temperature. Here, we model the low-temperature magnetic properties of the recently synthesized spin $S=1$ dimer system K${}_2$Ni(MoO${}_4$)$_2$ and propose it as a new candidate material for triplon and quintuplon condensation. Based on a first principles analysis of its electronic structure, we derive an effective spin-dimer model that we first solve within a mean-field approximation to refine its parameters in comparison to experiment. Finally, the model is solved by employing a numerically exact quantum Monte Carlo technique which leads to magnetic properties in good agreement with experimental magnetization and thermodynamic results. We discuss the emergent spin model of K${}_2$Ni(MoO${}_4$)$_2$ in view of condensation of magnetic excitations in a broad parameter regime. Finally, we comment on a geometrical peculiarity of the proposed model and discuss how it could host a supersolid phase upon structural distortions.
description: 7 pages, 4 figures + supplemental material of 6 pages, 6 figures. Comments are welcome