cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Empirical study on the efficiency of Spiking Neural Networks with axonal delays, and algorithm-hardware benchmarking
Creators: name: Patiño-Saucedo, Alberto
name: Yousefzadeh, Amirreza
name: Tang, Guangzhi
name: Corradi, Federico
name: Linares-Barranco, Bernabé
name: Sifalakis, Manolis
Publisher: name: arXiv
Year: 2023
Subjects: subject: Emerging Technologies (cs.ET)
subject: FOS: Computer and information sciences

description: The role of axonal synaptic delays in the efficacy and performance of artificial neural networks has been largely unexplored. In step-based analog-valued neural network models (ANNs), the concept is almost absent. In their spiking neuroscience-inspired counterparts, there is hardly a systematic account of their effects on model performance in terms of accuracy and number of synaptic operations.This paper proposes a methodology for accounting for axonal delays in the training loop of deep Spiking Neural Networks (SNNs), intending to efficiently solve machine learning tasks on data with rich temporal dependencies. We then conduct an empirical study of the effects of axonal delays on model performance during inference for the Adding task, a benchmark for sequential regression, and for the Spiking Heidelberg Digits dataset (SHD), commonly used for evaluating event-driven models. Quantitative results on the SHD show that SNNs incorporating axonal delays instead of explicit recurrent synapses achieve state-of-the-art, over 90% test accuracy while needing less than half trainable synapses. Additionally, we estimate the required memory in terms of total parameters and energy consumption of accomodating such delay-trained models on a modern neuromorphic accelerator. These estimations are based on the number of synaptic operations and the reference GF-22nm FDX CMOS technology. As a result, we demonstrate that a reduced parameterization, which incorporates axonal delays, leads to approximately 90% energy and memory reduction in digital hardware implementations for a similar performance in the aforementioned task.
Ionic selectivity and filtration from fragmented dehydration in multilayer graphene nanopores
Creators: name: Sahu, Subin
name: Zwolak, Michael
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Selective ion transport is a hallmark of biological ion channel behavior but is a major challenge to engineer into artificial membranes. Here, we demonstrate, with all-atom molecular dynamics simulations, that bare graphene nanopores yield measurable ion selectivity that varies over one to two orders of magnitude simply by changing the pore radius and number of graphene layers. Monolayer graphene does not display dehydration-induced selectivity until the pore radius is small enough to exclude the first hydration layer from inside the pore. Bi- and tri-layer graphene, though, display such selectivity already for a pore size that barely encroaches on the first hydration layer, which is due to the more significant water loss from the second hydration layer. Measurement of selectivity and activation barriers from both first and second hydration layer barriers will help elucidate the behavior of biological ion channels. Moreover, the energy barriers responsible for selectivity -- while small on the scale of hydration energies -- are already relatively large, i.e., many $k_B$. For separation of ions from water, therefore, one can exchange longer, larger radius pores for shorter, smaller radius pores, giving a practical method for maintaining exclusion efficiency while enhancing other properties (e.g., water throughput).
description: Minor fixes, updated references
Neural Discovery of Permutation Subgroups
Creators: name: Karjol, Pavan
name: Kashyap, Rohan
name: P, Prathosh A
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: We consider the problem of discovering subgroup $H$ of permutation group $S_{n}$. Unlike the traditional $H$-invariant networks wherein $H$ is assumed to be known, we present a method to discover the underlying subgroup, given that it satisfies certain conditions. Our results show that one could discover any subgroup of type $S_{k} (k \leq n)$ by learning an $S_{n}$-invariant function and a linear transformation. We also prove similar results for cyclic and dihedral subgroups. Finally, we provide a general theorem that can be extended to discover other subgroups of $S_{n}$. We also demonstrate the applicability of our results through numerical experiments on image-digit sum and symmetric polynomial regression tasks.
Relativistic simulations of long-lived reverse shocks in stratified ejecta: the origin of flares in GRB afterglows
Creators: name: Lamberts, Astrid
name: Daigne, Frédéric
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The X-ray light curves of the early afterglow phase from gamma-ray bursts present a puzzling variability, including flares. The origin of these flares is still debated, and often associated with a late activity of the central engine. We discuss an alternative scenario where the central engine remains short-lived and flares are produced by the propagation of a long-lived reverse shock in a stratified ejecta. Here we focus on the hydrodynamics of the shock interactions. We perform one-dimensional ultrarelativistic hydrodynamic simulations with different initial internal structure in the gamma-ray burst ejecta. We use them to extract bolometric light curves and compare with a previous study based on a simplified ballistic model. We find a good agreement between both approaches, with similar slopes and variability in the light curves, but identify several weaknesses in the ballistic model: the density is underestimated in the shocked regions, and more importantly, late shock reflections are not captured. With accurate dynamics provided by our hydrodynamic simulations, we confirm that internal shocks in the ejecta lead to the formation of dense shells. The interaction of the long-lived reverse shock with a dense shell then produces a fast and intense increase of the dissipated power. Assuming that the emission is due to the synchrotron radiation from shock-accelerated electrons, and that the external forward shock is radiatively inefficient, we find that this results in a bright flare in the X-ray lightcurve, with arrival times, shapes, and duration in agreement with the observed properties of X-ray flares in GRB afterglows.
description: Accepted for publication in MNRAS
Study of damped oscillating structures from charged and neutral K-meson electromagnetic form factors data
Creators: name: Dubnička, Stanislav
name: Dubničková, Anna Zuzana
name: Holka, Lukáš
name: Liptaj, Andrej
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The damped oscillating structures (OS) were recently revealed in the proton "effective" form factor (FF) data. For the time being they can be neither confirmed nor disproved by investigations of timelike data on the individual proton electric and proton magnetic FFs because their precision and reliability (especially of the proton electric FF data) has not achieved required level for this aim. On the other hand, conjectures that the OS are direct manifestations of the quark-gluon structure of the proton indicate that they must not be specific only for the proton and neutron, but that they should be present also for other hadrons. This opens a plausibility to find damped oscillatory structures also from the EM FFs data of such hadrons, for which adequate EM FFs data exist, by using the same procedure as for the proton. Consequently in this paper damped oscillatory structures are investigated in the EM FFs data of the charged and neutral $K$-mesons to be extracted from the corresponding production cross sections, $σ^{bare}_{tot}(e^+e^-\to K^+ K^-)$ measured from the threshold up to 64 GeV$^2$ and $σ^{bare}_{tot}(e^+e^-\to K_s K_L)$ measured from the threshold up to 9.5 GeV$^2$ of the total c.m. energy squared. The following results have been obtained. If the charged and neutral K-meson EM FFs timelike data are described by the three parametric formula by means of which OS have been revealed from the "effective" proton FF data then OS appear. If physically well founded Unitary and Analytic model of the K-meson EM structure is used for a description of the charged K-meson EM FFs data, no OS are visible. However, in the case of the neutral K-meson EM FF data one cannot make a definite decision. The overall results indicate that OS obtained from the "effective" proton FF data are likely an artefact of the three parametric formula which does not describe these data well.
Time-local unraveling of non-Markovian stochastic Schrödinger equations
Creators: name: Tilloy, Antoine
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Non-Markovian stochastic Schrödinger equations (NMSSE) are important tools in quantum mechanics, from the theory of open systems to foundations. Yet, in general, they are but formal objects: their solution can be computed numerically only in some specific cases or perturbatively. This article is focused on the NMSSE themselves rather than on the open-system evolution they unravel and aims at making them less abstract. Namely, we propose to write the stochastic realizations of linear NMSSE as averages over the solutions of an auxiliary equation with an additional random field. Our method yields a non-perturbative numerical simulation algorithm for generic linear NMSSE that can be made arbitrarily accurate for reasonably short times. For isotropic complex noises, the method extends from linear to non-linear NMSSE and allows to sample the solutions of norm-preserving NMSSE directly.
description: 7 pages
Twitter adoption, students perceptions, Big Five personality traits and learning outcome: Lessons learned from 3 case studies
Creators: name: Katrimpouza, Alexia
name: Tselios, Nikolaos
name: Kasimati, Maria-Christina
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: This study presents the results of the introduction of Twitter in the educational process. It examines the relationship of the tool s use with the participants learning outcome through a series of well-organized activities. Three studies were conducted in the context of 2 academic courses. The participation in the Twitter activity was voluntarily for the students. In all 3 studies the students who participated in the process had a higher laboratory grade than the students who did not participated. Students Conscientiousness and Openness to experience were related to their activity in one study. However, no relationship between the students personality traits and their grade was unveiled. Moreover, the students interventions in the activities are examined as well as the variation in their attitudes towards social media use in learning. The implications of the conducted studies are discussed extensively and a comparison with other related studies is presented.
Excited Scalar and Pseudoscalar Mesons in the Extended Linear Sigma Model
Creators: name: Parganlija, Denis
name: Giacosa, Francesco
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present an in-depth study of masses and decays of excited scalar and pseudoscalar $\bar{q}q$ states in the Extended Linear Sigma Model (eLSM). The model also contains ground-state scalar, pseudoscalar, vector and axial-vector mesons. The main objective is to study the consequences of the hypothesis that the $f_0(1790)$ resonance, observed a decade ago by the BES Collaboration and recently by LHCb, represents an excited scalar quarkonium. In addition we also analyse the possibility that the new $a_0(1950)$ resonance, observed recently by BABAR, may also be an excited scalar state. Both hypotheses receive justification in our approach although there appears to be some tension between the simultaneous interpretation of $f_0(1790)$/$a_0(1950)$ and pseudoscalar mesons $η(1295)$, $π(1300)$, $η(1440)$ and $K(1460)$ as excited $\bar{q}q$ states.
description: 28 pages, 6 tables, 1 figure. v2 (published version) contains further clarification of the model and results; typos have been corrected and references added
Anexos Artículo Niño et al. 2022, Instrumento Digitalis-ESO
Creators: name: Usart, Mireia
Publisher: name: Zenodo
Year: 2022
Subjects: Competencia Digital
Digital competence
Attitude
Actitud
Género
Gender

description: Tablas con la información correspondiente al análisis de factores del instrumento Digitalis-ESO y al análisis comparativo mediante estadística paramétrica (t-test con cálculo del tamaño de efecto mediante D de Cohen) del estudio con los datos de secundaria de la muestra de España.
Manipulating topological-insulator properties using quantum confinement
Creators: name: Kotulla, M.
name: Zülicke, U.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Recent discoveries have spurred the theoretical prediction and experimental realization of novel materials that have topological properties arising from band inversion. Such topological insulators are insulating in the bulk but have conductive surface or edge states. Topological materials show various unusual physical properties and are surmised to enable the creation of exotic Majorana-fermion quasiparticles. How the signatures of topological behavior evolve when the system size is reduced is interesting from both a fundamental and an application-oriented point of view, as such understanding may form the basis for tailoring systems to be in specific topological phases. This work considers the specific case of quantum-well confinement defining two-dimensional layers. Based on the effective-Hamiltonian description of bulk topological insulators, and using a harmonic-oscillator potential as an example for a softer-than-hard-wall confinement, we have studied the interplay of band inversion and size quantization. Our model system provides a useful platform for systematic study of the transition between the normal and topological phases, including the development of band inversion and the formation of massless-Dirac-fermion surface states. The effects of bare size quantization, two-dimensional-subband mixing, and electron-hole asymmetry are disentangled and their respective physical consequences elucidated.
description: 15 pages, 5 figures, IoP article style. Interactive simulations referenced in the article are available at https://www.dropbox.com/sh/ouq3e8p25m9kzvm/AAAgHZjdL8P0VWH_JzcH3rVRa?dl=0 . v2: added references & final paragraph in Conclusions. To appear in NJP
Direct linearising transform for three-dimensional discrete integrable systems: the lattice AKP, BKP and CKP equations
Creators: name: Fu, Wei
name: Nijhoff, Frank
Publisher: name: arXiv
Year: 2016
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: A unified framework is presented for the solution structure of three-dimensional discrete integrable systems, including the lattice AKP, BKP and CKP equations. This is done through the so-called direct linearising transform which establishes a general class of integral transforms between solutions. As a particular application, novel soliton-type solutions for the lattice CKP equation are obtained.
description: 21 pages, 3 figures
title: From the museum into the field and back – The digital link between museum objects and their origin
Creators: name: Zacke, Anne
name: Grigowski, Edouard
name: Fides, Friedeberg
name: Gösta, Hoffmann
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
Museums act on the interface between public and science and hence are in the best position to communicate scientific topics. We implement this by using our objects as translators: with classic exhibitions as traditional way of museum education. Complementing such classic educational tools, digital offerings are of increasing importance and widely implemented in museums today. Such facilities (e. g. museum apps, virtual tours, multitouch screens or displays etc.) are very attractive for younger guests or technophile visitors in general and hence help to improve the image of the institution, to attract further visitors and to awake interest in geoscientific topics. Digital offerings may provide additional or newest information in an understandable and easily accessible way. Within the scope of a granted project, we develop a tailor-made museum app for the Mineralogical Museum at the University of Bonn. Conventional applications usually give additional information about objects, provide short movies, audio sequences, etc. We go beyond this and use the app to link exclusive objects with their place of origin, guiding our visitors digitally from the museum into the field. Our guests will get the opportunity to explore different exciting geological sites across the country and to get in touch with the wide variety of geoscientific topics. We achieve this by implementing photogrammetric and laser-scanned 3D models of outstanding locations. The project is a cooperation with the mobile database of OutcropWizard and the project 30 Geotope³ – Germanys most beautiful geosites in 3D, both developed at the Institute of Geosciences at the University of Bonn.
Transient spin dynamics in a single-molecule magnet
Creators: name: Hammar, Henning
name: Fransson, Jonas
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We explore the limitations and validity of semi-classically formulated spin equations of motion. Using a single-molecule magnet as a test model, we employ three qualitatively different approximation schemes. From a microscopic model, we derive a generalized spin equation of motion in which the parameters have a non-local time-dependence. This dynamical equation is simplified to the Landau-Lifshitz-Gilbert equation with i) time-dependent, and ii) time-independent parameters. We show that transient dynamics is essentially non-existing in the latter approximation, while the former breaks down in the regime of strong coupling between the spin and the itinerant electrons.
description: 8 pages, 5 figures
Data-Driven Model Reduction and Nonlinear Model Predictive Control of an Air Separation Unit by Applied Koopman Theory
Creators: name: Schulze, Jan C.
name: Doncevic, Danimir T.
name: Erwes, Nils
name: Mitsos, Alexander
Publisher: name: arXiv
Year: 2023
Subjects: subject: Systems and Control (eess.SY)
subject: Machine Learning (cs.LG)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Achieving real-time capability is an essential prerequisite for the industrial implementation of nonlinear model predictive control (NMPC). Data-driven model reduction offers a way to obtain low-order control models from complex digital twins. In particular, data-driven approaches require little expert knowledge of the particular process and its model, and provide reduced models of a well-defined generic structure. Herein, we apply our recently proposed data-driven reduction strategy based on Koopman theory [Schulze et al. (2022), Comput. Chem. Eng.] to generate a low-order control model of an air separation unit (ASU). The reduced Koopman model combines autoencoders and linear latent dynamics and is constructed using machine learning. Further, we present an NMPC implementation that uses derivative computation tailored to the fixed block structure of reduced Koopman models. Our reduction approach with tailored NMPC implementation enables real-time NMPC of an ASU at an average CPU time decrease by 98 %.
Constraining the Mass Scale of a Lorentz-Violating Hamiltonian with the Measurement of Astrophysical Neutrino-Flavor Composition
Creators: name: Lai, Kwang-Chang
name: Lai, Wei-Hao
name: Lin, Guey-Lin
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We study Lorentz violation effects on flavor transitions of high energy astrophysical neutrinos. It is shown that the appearance of Lorentz violating Hamiltonian can drastically change the flavor transition probabilities of astrophysical neutrinos. Predictions of Lorentz violation effects on flavor compositions of astrophysical neutrinos arriving on Earth are compared with IceCube flavor composition measurement which analyzes astrophysical neutrino events in the energy range between $25~{\rm TeV}$ and $2.8~{\rm PeV}$. Such a comparison indicates that the future IceCube-Gen2 will be able to place stringent constraints on Lorentz violating Hamiltonian in the neutrino sector. We work out the expected sensitivities by IceCube-Gen2 on dimension-$3$ CPT-odd and dimension-$4$ CPT-even operators in Lorentz violating Hamiltonian. The expected sensitivities can improve on the current constraints obtained from other types of experiments by more than two orders of magnitudes for certain range of the parameter space.
description: Matches the published version
Lepton flavor universality violation without new sources of quark flavor violation
Creators: name: Kamenik, Jernej F.
name: Soreq, Yotam
name: Zupan, Jure
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We show that new physics models without new flavor violating interactions can explain the recent anomalies in the $b\to s\ell^+\ell^-$ transitions. The $b\to s\ell^+\ell^-$ arises from a $Z'$ penguin which automatically predicts the $V-A$ structure for the quark currents in the effective operators. This framework can be realized either in a renormalizable $U(1)'$ setup or be due to new strongly interacting dynamics. The di-muon resonance searches at the LHC are becoming sensitive to this scenario since the $Z'$ is relatively light, and could well be discovered in future searches by ATLAS and CMS.
description: 5 pages, 3 figures, correction of a mistake in eq. (16), Fig. 2 updated, conclusions unchanged
Copepods encounter rates from a model of escape jump behaviour in turbulence
Creators: name: Ardeshiri, H.
name: Schmitt, F. G.
name: Souissi, S.
name: Toschi, F.
name: Calzavarini, E.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Biological Physics (physics.bio-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: A key ecological parameter for planktonic copepods studies is their interspecies encounter rate which is driven by their behaviour and is strongly influenced by turbulence of the surrounding environment. A distinctive feature of copepods motility is their ability to perform quick displacements, often dubbed jumps, by means of powerful swimming strokes. Such a reaction has been associated to an escape behaviour from flow disturbances due to predators or other external dangers. In the present study, the encounter rate of copepods in a developed turbulent flow with intensity comparable to the one found in copepods' habitat is numerically investigated. This is done by means of a Lagrangian copepod (LC) model that mimics the jump escape reaction behaviour from localised high-shear rate fluctuations in the turbulent flows. Our analysis shows that the encounter rate for copepods of typical perception radius of ~ η, where η is the dissipative scale of turbulence, can be increased by a factor up to ~ 100 compared to the one experienced by passively transported fluid tracers. Furthermore, we address the effect of introducing in the LC model a minimal waiting time between consecutive jumps. It is shown that any encounter-rate enhancement is lost if such time goes beyond the dissipative time-scale of turbulence, τ_η. Because typically in the ocean η ~ 0.001m and τ_η ~ 1s, this provides stringent constraints on the turbulent-driven enhancement of encounter-rate due to a purely mechanical induced escape reaction.
description: 11 pages, 10 figures
Adaptive local surface refinement based on LR NURBS and its application to contact
Creators: name: Zimmermann, Christopher
name: Sauer, Roger A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Numerical Analysis (math.NA)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: A novel adaptive local surface refinement technique based on Locally Refined Non-Uniform Rational B-Splines (LR NURBS) is presented. LR NURBS can model complex geometries exactly and are the rational extension of LR B-splines. The local representation of the parameter space overcomes the drawback of non-existent local refinement in standard NURBS-based isogeometric analysis. For a convenient embedding into general finite element code, the Bézier extraction operator for LR NURBS is formulated. An automatic remeshing technique is presented that allows adaptive local refinement and coarsening of LR NURBS. In this work, LR NURBS are applied to contact computations of 3D solids and membranes. For solids, LR NURBS-enriched finite elements are used to discretize the contact surfaces with LR NURBS finite elements, while the rest of the body is discretized by linear Lagrange finite elements. For membranes, the entire surface is discretized by LR NURBS. Various numerical examples are shown, and they demonstrate the benefit of using LR NURBS: Compared to uniform refinement, LR NURBS can achieve high accuracy at lower computational cost.
description: Computational Mechanics (2017)
Unconventional magnetic anisotropy in one-dimentional Rashba system realized by adsorbing Gd atom on zigzag graphene nanoribbons
Creators: name: Qin, Zhenzhen
name: Qin, Guangzhao
name: Shao, Bin
name: Zuo, Xu
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The Rashba effect, a spin splitting in electronic band structure, attracts much attention for the potential applications in spintronics with no requirement of external magnetic field. Realizing one-dimensional (1D) Rashba system is a big challenge due to the difficulties of growing high-quality heavy-metal nanowires or introducing strong spin-orbit coupling (SOC) and broken inversion symmetry in flexible materials. Here, based on first-principles calculations, we propose a pathway to realize the Rashba spin-split by adsorbing Gd atom on zigzag graphene nanoribbons (Gd-ZGNR) and further investigate the magnetic anisotropy energy (MAE). Perpendicular MAE and unconventional MAE contributions in k-space are found in the self-assembled Gd-ZGNR system, which present a remarkable Rashba effect (the estimated strength is 1.89 eV Å) attributed to strong SOC (~65.6 meV) and the asymmetric adsorption site at the nanoribbons edge. Moreover, first-order MAE is connected to the intrinsic Rashba effect beyond the traditional second-order MAE, which is confirmed based on the analysis of electronic structures perturbed with SOC in comparison with metastable Gd-ZGNR at central symmetric adsorption site. The dependence of first-order MAE as well as Rashba effect of Gd-ZGNRs on the ribbon width are also examined. This work offers new perspective to achieve 1D Rashba system and provides fundamental understanding on the magnetic anisotropy, which would be of great significance for searching Majorana fermions and promoting the potential applications in spintronics.
description: 27 pages, 6 figures, supplementary information
Folding and cytoplasm viscoelasticity contribute jointly to chromosome dynamics
Creators: name: Polovnikov, K. E.
name: Gherardi, M.
name: Cosentino-Lagomarsino, M.
name: Tamm, M. V.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Subcellular Processes (q-bio.SC)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: The chromosome is a key player of cell physiology, and its dynamics provides valuable information about its physical organization. In both prokaryotes and eukaryotes, the short-time motion of chromosomal loci has been described as a Rouse model in a simple or viscoelastic medium. However, little emphasis has been put on the role played by the folded organization of chromosomes on the local dynamics. Clearly, stress-propagation, and thus dynamics, must be affected by such organization, but a theory allowing to extract such information from data, e.g.\ of two-point correlations, is lacking. Here, we describe a theoretical framework able to answer this general polymer dynamics question, and we provide a general scaling analysis of the stress-propagation time between two loci at a given arclength distance along the chromosomal coordinate. The results suggest a precise way to detect folding information from the dynamical coupling of chromosome segments. Additionally, we realize this framework in a specific theoretical model of a polymer with variable-range interactions in a viscoelastic medium characterized by a tunable scaling exponent, where we derive analytical estimates of the correlation functions.
description: 14 pages including supplementary materials
Trapped ions in Rydberg-dressed atomic gases
Creators: name: Secker, T.
name: Ewald, N.
name: Joger, J.
name: Fürst, H.
name: Feldker, T.
name: Gerritsma, R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We theoretically study trapped ions that are immersed in an ultracold gas of Rydberg-dressed atoms. By off-resonant coupling on a dipole-forbidden transition, the adiabatic atom-ion potential can be made repulsive. We study the energy exchange between the atoms and a single trapped ion and find that Langevin collisions are inhibited in the ultracold regime for these repulsive interactions. Therefore, the proposed system avoids recently observed ion heating in hybrid atom-ion systems caused by coupling to the ion's radio frequency trapping field and retains ultracold temperatures even in the presence of excess micromotion.
description: 9 pages, 5 figures including appendices
Approximate tensor-product preconditioners for very high order discontinuous Galerkin methods
Creators: name: Pazner, Will
name: Persson, Per-Olof
Publisher: name: arXiv
Year: 2017
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: In this paper, we develop a new tensor-product based preconditioner for discontinuous Galerkin methods with polynomial degrees higher than those typically employed. This preconditioner uses an automatic, purely algebraic method to approximate the exact block Jacobi preconditioner by Kronecker products of several small, one-dimensional matrices. Traditional matrix-based preconditioners require $\mathcal{O}(p^{2d})$ storage and $\mathcal{O}(p^{3d})$ computational work, where $p$ is the degree of basis polynomials used, and $d$ is the spatial dimension. Our SVD-based tensor-product preconditioner requires $\mathcal{O}(p^{d+1})$ storage, $\mathcal{O}(p^{d+1})$ work in two spatial dimensions, and $\mathcal{O}(p^{d+2})$ work in three spatial dimensions. Combined with a matrix-free Newton-Krylov solver, these preconditioners allow for the solution of DG systems in linear time in $p$ per degree of freedom in 2D, and reduce the computational complexity from $\mathcal{O}(p^9)$ to $\mathcal{O}(p^5)$ in 3D. Numerical results are shown in 2D and 3D for the advection and Euler equations, using polynomials of degree up to $p=15$. For many test cases, the preconditioner results in similar iteration counts when compared with the exact block Jacobi preconditioner, and performance is significantly improved for high polynomial degrees $p$.
description: 40 pages, 15 figures
The maximum isotropic energy of gamma-ray bursts
Creators: name: Atteia, J-L.
name: Heussaff, V.
name: Dezalay, J. -P.
name: Klotz, A.
name: Turpin, D.
name: Tsvetkova, A. E.
name: Frederiks, D. D.
name: Zolnierowski, Y.
name: Daigne, F.
name: Mochkovitch, R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The most energetic gamma-ray bursts (GRBs) are remarkable sources releasing huge amounts of energy on short timescales. Their prompt emission, which usually lasts few seconds, is so bright that it is visible across the whole observable universe. Studying these extreme events may provide clues on the nature of GRB progenitors and on the physical processes at work in relativistic jets. In this paper, we study the bright end of the isotropic energy distribution of long GRBs. We use two samples of long GRBs with redshift detected by Fermi/GBM or Konus-Wind, two instruments which measure the spectral shape and the energetics of the prompt emission accurately. We focus on GRBs within a range of redshifts z = 1 -- 5, a volume that contains a large number of energetic GRBs, and we propose a simple method to reconstruct the bright end of the GRB energy distribution from the observed one. We find that the GRB energy distribution cannot be described by a simple power law but requires a strong cutoff above $1-3 \times 10^{54}$ erg. We attribute this feature to an intrinsic limit on the energy per unit of solid angle radiated by gamma-ray bursts.
description: Revised version after correcting an error in the computation of the horizon of Konus GRBs (Table 3). Changes in the text are marked in bold. The main result is not affected
An Observational Diagnostic for Distinguishing Between Clouds and Haze in Hot Exoplanet Atmospheres
Creators: name: Kempton, Eliza M. -R.
name: Bean, Jacob L.
name: Parmentier, Vivien
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The nature of aerosols in hot exoplanet atmospheres is one of the primary vexing questions facing the exoplanet field. The complex chemistry, multiple formation pathways, and lack of easily identifiable spectral features associated with aerosols make it especially challenging to constrain their key properties. We propose a transmission spectroscopy technique to identify the primary aerosol formation mechanism for the most highly irradiated hot Jupiters (HIHJs). The technique is based on the expectation that the two key types of aerosols -- photochemically generated hazes and equilibrium condensate clouds -- are expected to form and persist in different regions of a highly irradiated planet's atmosphere. Haze can only be produced on the permanent daysides of tidally-locked hot Jupiters, and will be carried downwind by atmospheric dynamics to the evening terminator (seen as the trailing limb during transit). Clouds can only form in cooler regions on the night side and morning terminator of HIHJs (seen as the leading limb during transit). Because opposite limbs are expected to be impacted by different types of aerosols, ingress and egress spectra, which primarily probe opposing sides of the planet, will reveal the dominant aerosol formation mechanism. We show that the benchmark HIHJ, WASP-121b, has a transmission spectrum consistent with partial aerosol coverage and that ingress-egress spectroscopy would constrain the location and formation mechanism of those aerosols. In general, using this diagnostic we find that observations with JWST and potentially with HST should be able to distinguish between clouds and haze for currently known HIHJs.
description: 10 pages, 4 figures, accepted to ApJ Letters
Using Roman Space Telescope to find Dark Star candidates
Creators: name: Ilie, Cosmin
Publisher: name: Zenodo
Year: 2023
Subjects: Galaxy Surveys at High Redshift

description: Dark stars are luminous stellar objects, made primarily of hydrogen and helium, yet powered by dark matter. Formed in the early Universe at redshift z =10-20, some can grow supermassive by accretion. We investigate the detectability of supermassive dark stars (SMDSs) by the Roman Space Telescope (RST), motivated by our recent identification of several SMDSs candidates in the James Webb Space Telescope (JWST) data. Similarly to JWST, RST will be able to detect SMDSs at redshifts as high as z = 14 as photometric dropouts. Thanks to its much larger effective field of view, RST will have a larger detection probability of SMDSs candidates at these redshifts (compared to JWST). JWST, on the other hand, being sensitive to higher wavelengths, can probe a larger swath of the reframe SEDs of any given high redshift objects, and, as such, confirm the Dark Star nature of RST candidates via spectroscopy with NIRSpec or photometry with MIRI/NIRCam. In the talk I will elaborate on the various possible ways to differentiate between SMDSs and early galaxies using photometry, image morphology, and spectroscopy. The detection and confirmation of any supermassive dark star will provide evidence for annihilating dark matter. Moreover, such massive stars can also be natural progenitors of the supermassive black holes powering the extremely bright quasars observed at early times.
Folner tilings for actions of amenable groups
Creators: name: Conley, Clinton T.
name: Jackson, Steve
name: Kerr, David
name: Marks, Andrew
name: Seward, Brandon
name: Tucker-Drob, Robin
Publisher: name: arXiv
Year: 2017
Subjects: subject: Dynamical Systems (math.DS)
subject: Group Theory (math.GR)
subject: Operator Algebras (math.OA)
subject: FOS: Mathematics

description: We show that every probability-measure-preserving action of a countable amenable group G can be tiled, modulo a null set, using finitely many finite subsets of G ("shapes") with prescribed approximate invariance so that the collection of tiling centers for each shape is Borel. This is a dynamical version of the Downarowicz--Huczek--Zhang tiling theorem for countable amenable groups and strengthens the Ornstein--Weiss Rokhlin lemma. As an application we prove that, for every countably infinite amenable group G, the crossed product of a generic free minimal action of G on the Cantor set is Z-stable.
description: Minor revisions. Final version
Criteria for strict monotonicity of the mixed volume of convex polytopes
Creators: name: Bihan, Frédéric
name: Soprunov, Ivan
Publisher: name: arXiv
Year: 2017
Subjects: subject: Metric Geometry (math.MG)
subject: Commutative Algebra (math.AC)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: Let $P_1,\dots, P_n$ and $Q_1,\dots, Q_n$ be convex polytopes in $\mathbb{R}^n$ such that $P_i\subset Q_i$. It is well-known that the mixed volume has the monotonicity property: $V(P_1,\dots,P_n)\leq V(Q_1,\dots,Q_n)$. We give two criteria for when this inequality is strict in terms of essential collections of faces as well as mixed polyhedral subdivisions. This geometric result allows us to characterize sparse polynomial systems with Newton polytopes $P_1,\dots,P_n$ whose number of isolated solutions equals the normalized volume of the convex hull of $P_1\cup\dots\cup P_n$. In addition, we obtain an analog of Cramer's rule for sparse polynomial systems.
description: 18 pages, 3 figures. The proof of the second criterion has been improved (Section 4). Some improved bounds for lattice polytopes are added (Proposition 3.11)
Natural emergence of neutrino masses and dark matter from $R$-symmetry
Creators: name: Chakraborty, Sabyasachi
name: Chakrabortty, Joydeep
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We propose a supersymmetric extension of the Standard Model (SM) with a continuous global $U(1)_R$ symmetry. The $R$-charges of the SM fields are identified with that of their lepton numbers. As a result, both bilinear and trilinear `$R$-parity violating' (RPV) terms could be present at the superpotential. However, $R$-symmetry is not an exact symmetry as it is broken by supergravity effects. Hence, sneutrinos acquire a small vacuum expectation value in this framework. However, a suitable choice of basis ensures that the bilinear RPV terms can be completely rotated away from the superpotential and the scalar potential. On the other hand, the trilinear terms play a very crucial role in generating neutrino masses and mixing at the tree level. This is noticeably different from the typical $R$-parity violating Minimal Supersymmetric Standard Model. Also, gravitino mass turns out to be the order parameter of $R$-breaking and is directly related to the neutrino mass. We show that such a gravitino, within the mass range $200~\text{keV}\lesssim m_{3/2}\lesssim 0.1~\text{GeV}$ can be an excellent dark matter candidate. Finally, we looked into the collider implications of our framework.
description: 23 pages, one figure (added), title changed, discussion added on sneutrino vev basis, accepted for publication in JHEP
Consistency Between the Luminosity Function of Resolved Millisecond Pulsars and the Galactic Center Excess
Creators: name: Ploeg, Harrison
name: Gordon, Chris
name: Crocker, Roland
name: Macias, Oscar
Publisher: name: arXiv
Year: 2017
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: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Fermi Large Area Telescope data reveal an excess of GeV gamma rays from the direction of the Galactic Center and bulge. Several explanations have been proposed for this excess including an unresolved population of millisecond pulsars (MSPs) and self-annihilating dark matter. It has been claimed that a key discriminant for or against the MSP explanation can be extracted from the properties of the luminosity function describing this source population. Specifically, is the luminosity function of the putative MSPs in the Galactic Center consistent with that characterizing the resolved MSPs in the Galactic disk? To investigate this we have used a Bayesian Markov Chain Monte Carlo to evaluate the posterior distribution of the parameters of the MSP luminosity function describing both resolved MSPs and the Galactic Center excess. At variance with some other claims, our analysis reveals that, within current uncertainties, both data sets can be well fit with the same luminosity function.
description: 37 pages, 18 figures; V2: updated references and extended discussion slightly. V3: Additional material added, conclusions unchanged, matches version to appear in JCAP
Towards characterization of edge-cloud continuum
Creators: name: Khalyeyev, Danylo
name: Bureš, Tomáš
name: Hnětynka, Petr
Publisher: name: arXiv
Year: 2023
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: Internet of Things and cloud computing are two technological paradigms that reached widespread adoption in recent years. These paradigms are complementary: IoT applications often rely on the computational resources of the cloud to process the data generated by IoT devices. The highly distributed nature of IoT applications and the giant amounts of data involved led to significant parts of computation being moved from the centralized cloud to the edge of the network. This gave rise to new hybrid paradigms, such as edge-cloud computing and fog computing. Recent advances in IoT hardware, combined with the continued increase in complexity and variability of the edge-cloud environment, led to an emergence of a new vision of edge-cloud continuum: the next step of integration between the IoT and the cloud, where software components can seamlessly move between the levels of computational hierarchy. However, as this concept is very new, there is still no established view of what exactly it entails. Several views on the future edge-cloud continuum have been proposed, each with its own set of requirements and expected characteristics. In order to move the discussion of this concept forward, these views need to be put into a coherent picture. In this paper, we provide a review and generalization of the existing literature on edge-cloud continuum, point out its expected features, and discuss the challenges that need to be addressed in order to bring about this envisioned environment for the next generation of smart distributed applications.
title: Digital educational tools – smart solutions for heavy stuff
Creators: name: Grigowski, Edouard
name: Zacke, Anne
name: Friedeberg, Fides
name: Hoffmann, Gösta
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
Although geoscientific topics (e. g. climate change, natural hazards, geoheritage) engage public, media and politicians, the visibility of geosciences as subject labs behind. Classic ways of public relations are still relevant, but we need additional, complementing communication instruments to transport gescientific topics. Such instruments are digital offerings. They are very attractive for younger people and technophile persons in general. They are easily accessible and a very useful medium to address our topics to the public. Additionally, they are up-to-date educational tools and can help to explain complicated geoscientific contexts in an understandable, modern and brisk way. As geoscientific museum we naturally use classic ways of communication – our exhibitions – but we also work on digital solutions to reach a wider audience and get people attracted. The granted project is a cooperation with the mobile database of OutcropWizard and the project 30 Geotope³ – Germanys most beautiful geosites in 3D, both developed at the Institute of Geosciences at the University of Bonn. We develop a tailor-made museum app that goes beyond the function of conventional applications. They usually give additional information about objects, provide short movies, audio sequences, etc. We develop the app to link exclusive objects in our showcases with their place of origin, guiding our visitors digitally from the museum into the field. Our guests will get the opportunity to explore different exciting geological sites across the country and to get in touch with the wide variety of geoscientific topics. We achieve this by implementing photogrammetric and laser-scanned 3D models of outstanding locations.
Grabbing power line conductors based on the measurements of the magnetic field strength
Creators: name: Vasiljevic, Goran
name: Martinovic, Dean
name: Orsag, Matko
name: Bogdan, Stjepan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: This paper presents the method for the localization and grabbing of the long straight conductor based only on the magnetic field generated by the alternating current flowing through the conductor. The method uses two magnetometers mounted on the robot arm end-effector for localization. This location is then used to determine needed robot movement in order to grab the conductor. The method was tested in the laboratory conditions using the Schunk LWA 4P 6-axis robot arm.
description: 2021 Aerial Robotic Systems Physically Interacting with the Environment (AIRPHARO). arXiv admin note: text overlap with arXiv:2206.09169