cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Vacuum energy as dark matter
Creators: name: Albareti, F. D.
name: Cembranos, J. A. R.
name: Maroto, A. L.
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider the vacuum energy of massive quantum fields in an expanding universe. We define a conserved renormalized energy-momentum tensor by means of a comoving cutoff regularization. Using exact solutions for de Sitter space-time, we show that in a certain range of mass and renormalization scales there is a contribution to the vacuum energy density that scales as nonrelativistic matter and that such a contribution becomes dominant at late times. By means of the WKB approximation, we find that these results can be extended to arbitrary Robertson-Walker geometries. We study the range of parameters in which the vacuum energy density would be compatible with current limits on dark matter abundance. Finally, by calculating the vacuum energy in a perturbed Robertson-Walker background, we obtain the speed of sound of density perturbations and show that the vacuum energy density contrast can grow on sub-Hubble scales as in standard cold dark matter scenarios.
description: 13 pages, 6 figures. Version published in PRD
Preserving Information from the Beginning to the End of time in a Robertson-Walker Spacetime
Creators: name: Mancini, Stefano
name: Pierini, Roberto
name: Wilde, Mark M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Preserving information stored in a physical system subjected to noise can be modeled in a communication-theoretic paradigm, in which storage and retrieval correspond to an input encoding and output decoding, respectively. The encoding and decoding are then constructed in such a way as to protect against the action of a given noisy quantum channel. This paper considers the situation in which the noise is not due to technological imperfections, but rather to the physical laws governing the evolution of the universe. In particular, we consider the dynamics of quantum systems under a 1+1 Robertson-Walker spacetime and find that the noise imparted to them is equivalent to the well known amplitude damping channel. Since one might be interested in preserving both classical and quantum information in such a scenario, we study trade-off coding strategies and determine a region of achievable rates for the preservation of both kinds of information. For applications beyond the physical setting studied here, we also determine a trade-off between achievable rates of classical and quantum information preservation when entanglement assistance is available.
description: 19 pages, 3 figures. Presentation updated, matches the published version
Transition2BIO Project Deliverable D2.2 Report on Large awareness and public engagement event
Creators: name: Bielikova, Jana
Publisher: name: Zenodo
Year: 2021

description: This document is the project deliverable D2.2 Report on Large awareness and public engagement event of the Transition2BIO Horizon 2020 project which is funded under the Grant Agreement 101000539. The deliverable is about the 1st version of the Report on Large scale awareness and public engagement events.
An efficient approach to approximating the pair distribution function of the inhomogeneous hard-sphere fluid
Creators: name: Lurie-Gregg, Paho
name: Schulte, Jeff B.
name: Roundy, David
Publisher: name: arXiv
Year: 2014
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We introduce an approximation for the pair distribution function of the inhomogeneous hard sphere fluid. Our approximation makes use of our recently published averaged pair distribution function at contact which has been shown to accurately reproduce the averaged pair distribution function at contact for inhomogeneous density distributions. This approach achieves greater computational efficiency than previous approaches by enabling the use of exclusively fixed-kernel convolutions and thus allowing an implementation using fast Fourier transforms. We compare results for our pair distribution approximation with two previously published works and Monte-Carlo simulation, showing favorable results.
Spectrum and Franck--Condon factors of interacting suspended single-wall carbon nanotubes
Creators: name: Donarini, Andrea
name: Yar, Abdullah
name: Grifoni, Milena
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: 530 Physik

description: A low-energy theory of suspended carbon nanotube quantum dots in weak tunnelling coupling with metallic leads is presented. The focus is on the dependence of the spectrum and the Franck–Condon factors on the geometry of the junction including several vibronic modes. The relative size and the relative position of the dot and its associated vibrons strongly influence the electromechanical properties of the system. A detailed analysis of the complete parameters space reveals different regimes: in the short vibron regime the tunnelling of an electron into the nanotube generates a plasmon–vibron excitation, whereas in the long vibron regime polaron excitations dominate the scenario. The small, position-dependent Franck–Condon couplings of the small vibron regime convert into uniform, large couplings in the long vibron regime. Selection rules for the excitations of the different plasmon–vibron modes via electronic tunnelling events are also derived.
Transition2BIO Project Deliverable D3.5 Report on Future skills for Bioeconomy workshops – 1st version
Creators: name: M. Grande
name: S. Maccaferri
name: D. Viaggi
Publisher: name: Zenodo
Year: 2021

description: This document is the project deliverableD3.5 Report on Future skills for Bioeconomy workshops – 1st version of the Transition2BIO Horizon 2020 project which is funded under the Grant Agreement 101000539. The deliverable is about the first version of the Report on Future skills for Bioeconomy workshops.
Transition2BIO Project Deliverable D4.3 First Consolidated Action Plan of Awareness and Communication Activities
Creators: name: Albertini, Susanna
Publisher: name: Zenodo
Year: 2021

description: This document is the project deliverable D4.3 First Consolidated Action Plan of Awareness and Communication Activities of the Transition2BIO Horizon 2020 project which is funded under the Grant Agreement 101000539. The deliverable is about the first consolidated action plan of Awareness and Communication activities.
A note on the runtime of a faulty Hamiltonian oracle
Creators: name: Temme, Kristan
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In these notes we show that it is impossible to obtain a quantum speedup for a faulty Hamiltonian oracle. The effect of dephasing noise to this continuous time oracle model has first been investigated in [1]. The authors consider a faulty oracle described by a continuous time master equation that acts as dephasing noise in the basis determined by the marked item. The analysis focuses on the implementation with a particular driving Hamiltonian. A universal lower bound for this oracle model, which rules out a better performance with a different driving Hamiltonian has so far been lacking. In this note, we derive an adversary type lower bound which shows that the evolution time T has to be at least in the order of N, i.e. the size of the search space, when the error rate of the oracle is constant. For the standard quantum oracle model this result was first proven in [2]. This note can be seen as an extension of their result to the continuous time setting.
Modeling FX market activity around macroeconomic news: a Hawkes process approach
Creators: name: Rambaldi, Marcello
name: Pennesi, Paris
name: Lillo, Fabrizio
Publisher: name: arXiv
Year: 2014
Subjects: subject: Trading and Market Microstructure (q-fin.TR)
subject: FOS: Economics and business

description: We present a Hawkes model approach to foreign exchange market in which the high frequency price dynamics is affected by a self exciting mechanism and an exogenous component, generated by the pre-announced arrival of macroeconomic news. By focusing on time windows around the news announcement, we find that the model is able to capture the increase of trading activity after the news, both when the news has a sizeable effect on volatility and when this effect is negligible, either because the news in not important or because the announcement is in line with the forecast by analysts. We extend the model by considering non-causal effects, due to the fact that the existence of the news (but not its content) is known by the market before the announcement.
description: 16 pages, 12 figures. Accepted for publication in Physical Review E (2015)
Entwicklung und Optimierung von Software für eine mikrocontrollerbasierte Steuerung einer Messeinheit mit High-Speed USB-Schnittstelle
Creators: name: Rother, Niklas
Publisher: name: Hannover : Gottfried Wilhelm Leibniz Universität, Institut für Grundlagen der Elektrotechnik und Messtechnik
Year: 2015
Subjects: subject: USB-Messkarte
subject: Messeinheit
subject: Software
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau::621 | Angewandte Physik::621,3 | Elektrotechnik, Elektronik

description: [no abstract available]
Konzeptionierung und Implementierung einer hybriden MAC-Layer-Architektur für Paket-basierte Powerline Kommunikation auf einem FPGA
Creators: name: Rother, Niklas
Publisher: name: Hannover : Gottfried Wilhelm Leibniz Universität, Institut für Mikroelektronische Systeme
Year: 2017
Subjects: subject: MAC-Layer-Architektur
subject: FPGA
subject: Field Programmable Gate Array
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau::621 | Angewandte Physik::621,3 | Elektrotechnik, Elektronik

description: [no abstract available]
Manipulation of p-wave scattering of cold atoms in low dimensions using the magnetic field vector
Creators: name: Peng, Shi-Guo
name: Tan, Shina
name: Jiang, Kaijun
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: It is well-known that the magnetic Feshbach resonances of cold atoms are sensitive to the magnitude of the external magnetic field. Much less attention has been paid to the direction of such a field. In this work we calculate the scattering properties of spin polarized fermionic atoms in reduced dimensions, near a p-wave Feshbach resonance. Because of spatial anisotropy of the p-wave interaction, the scattering has nontrivial dependence on both the magnitude and the direction of the magnetic field. In addition, we identify an inelastic scattering process which is impossible in the isotropic-interaction model; the rate of this process depends considerably on the direction of the magnetic field. Significantly, an EPR entangled pair of identical fermions may be produced during this inelastic collision. This work opens a new method to manipulate resonant cold atomic interactions.
description: 5 pages,3 figures
Anisotropic expansion and SNIa: an open issue
Creators: name: Jimenez, Jose Beltran
name: Salzano, Vincenzo
name: Lazkoz, Ruth
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We review the appropriateness of using SNIa observations to detect potential signatures of anisotropic expansion in the Universe. We focus on Union2 and SNLS3 SNIa datasets and use the hemispherical comparison method to detect possible anisotropic features. Unlike some previous works where non-diagonal elements of the covariance matrix were neglected, we use the full covariance matrix of the SNIa data, thus obtaining more realistic and not underestimated errors. As a matter of fact, the significance of previously claimed detections of a preferred direction in the Union2 dataset completely disappears once we include the effects of using the full covariance matrix. Moreover, we also find that such a a preferred direction is aligned with the orthogonal direction of the SDSS observational plane and this suggests a clear indication that the SDSS subsample of the Union2 dataset introduces a significant biased, making the detected preferred direction unphysical. We thus find that current SNIa surveys are inappropriate to test anisotropic features due to their highly non-homogeneous angular distribution in the sky. In addition, after removal of the highest inhomogeneous sub-samples, the number of SNIa is too low. Finally, we take advantage of the particular distribution of SNLS SNIa sub-sample in the SNLS3 data set, in which the observations were taken along 4 different directions. We fit each direction independently and find consistent results at the 1$σ$ level. Although the likelihoods peak at relatively different values of $Ω_m$,the low number of data along each direction gives rise to large errors so that the likelihoods are sufficiently broad as to overlap within 1$σ$.
description: 12 pages, 7 figures. V2 to match published version
The self-energy of an impurity in an ideal Fermi gas to second order in the interaction strength
Creators: name: Trefzger, Christian
name: Castin, Yvan
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We study in three dimensions the problem of a spatially homogeneous zero-temperature ideal Fermi gas of spin-polarized particles of mass $m$ perturbed by the presence of a single distinguishable impurity of mass $M$. The interaction between the impurity and the fermions involves only the partial $s$-wave through the scattering length $a$, and has negligible range $b$ compared to the inverse Fermi wave number $1/\kf$ of the gas. Through the interactions with the Fermi gas the impurity gives birth to a quasi-particle, which will be here a Fermi polaron (or more precisely a {\sl monomeron}). We consider the general case of an impurity moving with wave vector $\KK\neq\OO$: Then the quasi-particle acquires a finite lifetime in its initial momentum channel because it can radiate particle-hole pairs in the Fermi sea. A description of the system using a variational approach, based on a finite number of particle-hole excitations of the Fermi sea, then becomes inappropriate around $\KK=\mathbf{0}$. We rely thus upon perturbation theory, where the small and negative parameter $\kf a\to0^-$ excludes any branches other than the monomeronic one in the ground state (as e.g.\ the dimeronic one), and allows us a systematic study of the system. We calculate the impurity self-energy $Σ^{(2)}(\KK,ω)$ up to second order included in $a$. Remarkably, we obtain an analytical explicit expression for $Σ^{(2)}(\KK,ω)$ allowing us to study its derivatives in the plane $(K,ω)$. These present interesting singularities, which in general appear in the third order derivatives $\partial^3 Σ^{(2)}(\KK,ω)$. In the special case of equal masses, $M=m$, singularities appear already in the physically more accessible second order derivatives $\partial^2 Σ^{(2)}(\KK,ω)$; using a self-consistent heuristic approach based on $Σ^{(2)}$ we then regularise the divergence of the second order derivative $\partial\_K^2 ΔE(\KK)$ of the complex energy of the quasi-particle found in reference [C. Trefzger, Y. Castin, Europhys. Lett. {\bf 104}, 50005 (2013)] at $K=\kf$, and we predict an interesting scaling law in the neighborhood of $K=\kf$. As a by product of our theory we have access to all moments of the momentum of the particle-hole pair emitted by the impurity while damping its motion in the Fermi sea, at the level of Fermi's golden rule.
description: final version in english and in french - version finale en anglais et en fran\c{c}ais
Laser-sub-cycle two-dimensional electron momentum mapping using orthogonal two-color fields
Creators: name: Zhang, Li
name: Xie, Xinhua
name: Roither, Stefan
name: Kartashov, Daniil
name: Wang, YanLan
name: Wang, ChuanLiang
name: Schöffler, Markus
name: Shafir, Dror
name: Corkum, Paul
name: Baltuška, Andrius
name: Ivanov, Igor
name: Kheifets, Anatoli
name: Liu, XiaoJun
name: Staudte, André
name: Kitzler, Markus
Publisher: name: arXiv
Year: 2014
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The two-dimensional sub-cycle-time to electron momentum mapping provided by orthogonal two-color laser fields is applied to photoelectron spectroscopy. Using neon as the example we gain experimental access to the dynamics of emitted electron wave packets in electron momenta spectra measured by coincidence momentum imaging. We demonstrate the opportunities provided by this time-to-momentum mapping by investigating the influence of the parent ion on the emitted electrons on laser-sub-cycle times. It is found that depending on their sub-cycle birth time the trajectories of photoelectrons are affected differently by the ion's Coulomb field.
Parametrization of a Hybrid Component Production Process Chain Based on Semantically Annotated Data
Creators: name: Wawer, Max Leo
name: Sheveleva, Tatyana
name: Koepler, Oliver
name: Nürnberger, Florian
name: Mozgova, Iryna
name: Lachmayer, Roland
name: Auer, Sören
Publisher: name: Novi Sad : University of Novi Sad
Year: 2022
Subjects: subject: Human Machine Interaction
subject: Semantic Annotation
subject: Knowledge Management System
subject: Process Monitoring
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: The development of a novel manufacturing process chain is a complex scientific challenge and requires interdisciplinary collaboration, as well as technological solutions that extend the boundaries of automation and customize the information flows between different organizational units. Due to these challenges an approach to parametrize each step in the production chain and its careful documentation must be considered. This publication describes an approach to provide seamless digital access to sample and processrelated data through semantic annotation. In this way, it can be traced how and with which process layouts of the individual process steps a sample was manufactured along the process chain. The implementation of the approach is shown in the example of a novel process chain for the production of multi-material bearing washers within the Collaborative Research Center (CRC) 1153. A workflow based on a semantic annotation using a domainspecific vocabulary is presented, which allows to obtain the necessary process parameter values according to the individual requirements of the multi-material component.
title: Évaluer les compétences langagières dans un processus migratoire – l’exemple du Québec : une démarche discriminatoire et élitiste ?
Creators: name: Chénier, Christophe
Publisher: name: La Revue LEeE
Year: 2023
Subjects: évaluation en langue étrangère
évaluation discriminatoire
Français langue étrangère
compétence langagière
récit de pratique

description: Ce récit de pratique relate mes expériences professionnelles en tant qu’examinateur pour un test de français langue étrangère utilisé dans le contexte de la sélection des immigrant·es au Québec. L’objectif du texte est de montrer que ces pratiques évaluatives sont discriminatoires et engendre des conséquences non conformes aux principes démocratiques pour les personnes immigrantes peu scolarisées et celles ayant le français comme langue première ou de scolarité. Pour ce faire, le processus de sélection des immigrant·es est présenté, ainsi que mes expériences professionnelles, le processus évaluatif et la nature de la discrimination identifiée. Ensuite, la littérature scientifique est mobilisée pour tenter de comprendre la source de ce problème. La littérature sur les référentiels de compétence en langue étrangère est exploitée, de même que l’œuvre théorique de Hulstijn, qui permet de reconceptualiser la compétence langagière en deux compétences distinctes. La première compétence, dite élémentaire, regroupe les savoirs et habiletés partagées par toutes les personnes ayant une langue donnée comme langue première. La seconde, dite avancée, désigne les savoirs et habiletés davantage académiques. C’est cette dualité qui expliquerait la nature discriminatoire du processus évaluatif dans le cadre de la sélection des immigrant·es. Finalement, un retour réflexif justifie la pertinence de ce récit de pratique pour le champ de l’éducation et de la formation.
Regionale und soziale Chancenungleichheiten beim Zugang zum Gymnasium
Creators: name: Leemann, Regula Julia
name: Pfeifer Brändli, Andrea
name: Imdorf, Christian
Publisher: name: Bern : Schweizerische Akademie der Geistes- und Sozialwissenschaften
Year: 2023
Subjects: subject: Bildungsungleichheiten
subject: Region
subject: Soziale Herkunft
subject: Schweiz
subject: Gymnasium
subject: Dewey Decimal Classification::300 | Sozialwissenschaften, Soziologie, Anthropologie

description: Wir untersuchen in diesem Beitrag, inwiefern sich die kantonalen Unterschiede in der Bereitstellung gymnasialer Ausbildungsplätze auf die regionale und soziale Chancengleichheit beim Zugang zum Gymnasium auswirken. Dabei gehen wir von zwei Annahmen aus: Erstens hängt die Wahrscheinlichkeit für Schüler·innen, in ein Gymnasium einzutreten, vom Angebot an Ausbildungsplätzen im Kanton und damit vom Wohnort ab; d. h., wir gehen von regionalen Chancenungleichheiten aus. Zweitens vermuten wir, dass die Ungleichheit beim Zugang zwischen Schüler·innen aus privilegierten und aus sozial benachteiligten Familien bei steigendem Angebot an Ausbildungsplätzen abnimmt, da sich der Wettbewerb um die begehrten Ausbildungsplätze verkleinert. Damit reduziert sich auch die soziale Chancenungleichheit, und Schüler·innen aus weniger privilegierten Familien haben trotz geringeren kulturellen, ökonomischen und sozialen Ressourcen bessere Chancen, in ein Gymnasium einzutreten.
Unconventional topological phase transitions in helical Shiba chains
Creators: name: Pientka, Falko
name: Glazman, Leonid I.
name: von Oppen, Felix
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Chains of magnetic impurities placed on a superconducting substrate and forming helical spin order provide a promising venue for realizing a topological superconducting phase. An effective tight-binding description of such helical Shiba chains involves long-range (power-law) hopping and pairing amplitudes which induce an unconventional topological critical point. At the critical point, we find exponentially localized Majorana bound states with a short localization length unrelated to a topological gap. Away from the critical point, this exponential decay develops a power-law tail. Our analytical results have encouraging implications for experiment.
description: 4+ pages, 2 figures, plus supplementary material, v3: added references and minor refinements; published version
Dihadron azimuthal correlations at large pseudo-rapidity difference in multiplicity-selected d+Au collisions by STAR
Creators: name: Wang, Fuqiang
Publisher: name: arXiv
Year: 2014
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The long-range pseudo-rapidity correlations observed in pp and p+Pb collisions at the LHC have stimulated extensive interest. The tantalizing observation of similar effect by PHENIX calls for careful examination of the RHIC d+Au data. In this talk, we present dihadron correlations in multiplicity-selected d+Au collisions by STAR, in both $Δϕ$ and $Δη$ and from both TPC and FTPC.
description: 4 pages, 4 figures. Contributed talk to Hard Probes 2013, Cape Town, South Africa, Nov. 4-8, 2013
A Case Study on Multi-Softcore Aided Hardware Architectures for Powerline MAC-Layer
Creators: name: Rother, Niklas
name: Stuckenberg, Tobias
name: Nolting, Stephan
name: Uhlemann, Christof
name: Blume, Holger
Publisher: name: Hannover : Institutionelles Repositorium der Leibniz Universität Hannover
Year: 2023
Subjects: subject: FPGA
subject: GCC
subject: Multi-Core
subject: Powerline
subject: Softcore
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau::621 | Angewandte Physik::621,3 | Elektrotechnik, Elektronik

description: Powerline communication is a promising technology for connecting Internet of Things (IoT) applications, where devices have strict limitations regarding available installation space and power dissipation. Especially the wiring of these devices benefits from not having additional cables for network connection. Thus, saving costs and additional installation effort. In this paper a very resource-efficient implementation of a HomePlug 1.0.1 [5] compatible powerline MAC layer, which is used to control the data flow and link status of a powerline connection, is presented. The MAC layer is implemented in two variants, using state machines and softcore processors. A comparison of the two approaches shows that the softcore design used up to 78 % less FPGA ressources and is superior in terms of flexibility and maintainability.
Enhanced spin Hall effect by electron correlations in CuBi alloys
Creators: name: Gu, Bo
name: Xu, Zhuo
name: Mori, Michiyasu
name: Ziman, Timothy
name: Maekawa, Sadamichi
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A recent experiment in CuBi alloys obtained a large spin Hall angle (SHA) of -0.24 (Niimi et al. Phys. Rev. Lett. 109, 156602 (2012)). We find that the SHA can be dramatically enhanced by Bi impurities close to the Cu surface. The mechanisms of this enhancement are two-fold. One is that the localized impurity state on surface has a decreased hybridization and combined with Coulomb correlation effect. The other comes from the low-dimensional state of conduction electrons on surface, which results in a further enhancement of skew scattering by impurities. Furthermore, we note that a discrepancy in sign of SHA between the experiment and previous theories is simply caused by different definitions of SHA. This re-establishes skew scattering as the essential mechanism underlying the spin Hall effect in CuBi alloys.
description: 5 pages, 1 figure
A study of effect of NPA on the profitability of Indian banks
Creators: name: ., MGMulla
Publisher: name: figshare
Year: 2023
Subjects: Accounting theory and standards
Financial accounting
Sustainability accounting and reporting

description: The present paper deals with the type of non-performing assets the Indian banking sector is facing. It also identifies the causes of NPA in the Indian banking sector and what are its effect on the Indian banking sector.
Twisted Exponents and Twisted Frobenius-Schur Indicators for Hopf Algebras
Creators: name: Sage, Daniel S.
name: Vega, Maria D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Algebra (math.QA)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 16T05 (Primary), 20C15 (Secondary)

description: Classically, the exponent of a group is the least common multiple of the orders of its elements. This notion was generalized by Etingof and Gelaki to the context of Hopf algebras. Kashina, Sommerhauser and Zhu later observed that there is a strong connection between exponents and Frobenius-Schur indicators. In this paper, we introduce the notion of twisted exponents and show that there is a similar relationship between the twisted exponent and the twisted Frobenius-Schur indicators defined in previous work of the authors. In particular, we exhibit a new formula for the twisted Frobenius-Schur indicators and use it to prove periodicity and rationality statements for the twisted indicators.
Supplementary Material from Analytical and numerical study of anti-plane elastic wave scattering in a structured quadrant subjected to a boundary point load
Creators: name: Nieves, Michael John
name: Kisil, Anastasia
name: Mishuris, Gennady
Publisher: name: The Royal Society
Year: 2024
Subjects: classificationCode: 490109
subject: Theoretical and applied mechanics

description: Supplementary Material. Sections A contains the derivation of the steady state equations considered in the paper. Section B contains the proof of a result used in the solution of the Wiener-Hopf equation obtained from the problem involving the constrained quadrant.
Soft Decoding of a Qubit Readout Apparatus
Creators: name: D'Anjou, B.
name: Coish, W. A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Qubit readout is commonly performed by thresholding a collection of analog detector signals to obtain a sequence of single-shot bit values. The intrinsic irreversibility of the mapping from analog to digital signals discards soft information associated with an \emph{a posteriori} confidence that can be assigned to each bit value when a detector is well characterized. Accounting for soft information, we show significant improvements in enhanced state detection with the quantum repetition code as well as quantum state or parameter estimation. These advantages persist in spite of non-Gaussian features of realistic readout models, experimentally relevant small numbers of qubits, and finite encoding errors. These results show useful and achievable advantages for a wide range of current experiments on quantum state tomography, parameter estimation, and qubit readout.
description: 17 pages, 8 figures; updated text, figures, supplemental material and references
A bayesian approach for imputation of censored survival data
Creators: name: Moghaddam, Shirin
name: Newell, John
name: Hinde, John
Publisher: name: University of Limerick
Year: 2023
Subjects: Mathematical sciences

description: A common feature of much survival data is censoring due to incompletely observed lifetimes. Survival analysis methods and models have been designed to take account of this and provide appropriate relevant summaries, such as the Kaplan–Meier plot and the commonly quoted median survival time of the group under consideration. However, a single summary is not really a relevant quantity for communication to an individual patient, as it conveys no notion of variability and uncertainty, and the Kaplan–Meier plot can be difficult for the patient to understand and also is often mis-interpreted, even by some physicians. This paper considers an alternative approach of treating the censored data as a form of missing, incomplete data and proposes an imputation scheme to construct a completed dataset. This allows the use of standard descriptive statistics and graphical displays to convey both typical outcomes and the associated variability. We propose a Bayesian approach to impute any censored observations, making use of other information in the dataset, and provide a completed dataset. This can then be used for standard displays, summaries, and even, in theory, analysis and model fitting. We particularly focus on the data visualisation advantages of the completed data, allowing displays such as density plots, boxplots, etc, to complement the usual Kaplan–Meier display of the original dataset. We study the performance of this approach through a simulation study and consider its application to two clinical examples.
Magnetic proximity effect at the interface of two-dimensional materials and magnetic oxide insulators
Creators: name: Hua, Junxiong
name: Luo, Jiangbo
name: Zheng, Yuntian
name: Chen, Jiayu
name: Omar, Ganesh Ji
name: Wee, Andrew Thye Shen
name: Ariando, A.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Two-dimensional (2D) materials provide a platform for developing novel spintronic devices and circuits for low-power electronics. In particular, inducing magnetism and injecting spins in graphene have promised the emerging field of graphene spintronics. This review focuses on the magnetic proximity effect at the interface of 2D materials and magnetic oxide insulators. We highlight the unique spin-related phenomena arising from magnetic exchange interaction and spin-orbital coupling in 2D materials coupled with magnetic oxides. We also describe the fabrication of multifunctional hybrid devices based on spin transport. We conclude with a perspective of the field and highlight challenges for the design and fabrication of 2D spintronic devices and their potential applications in information storage and logic devices.
description: 32 pages, 16 figures, 106 references
A flood monitoring tool for urban areas using satellite, weather and social data
Creators: name: Andreadis, Stelios
name: Moumtzidou, Anastasia
name: Gialampoukidis, IIias
name: Vrochidis, Stefanos
name: Kompatsiaris, Ioannis
Publisher: name: Zenodo
Year: 2018

description: Large streams of open data become available on a daily basis and are expected to support a number of public bodies and water authorities in their safety policies and strategies. At the European level, more than 2.5 million of Sentinel-1A products are published online from the European Space Agency, corresponding to 3 million GB of data and 350,000 products. Copernicus data have already paved the way to monitor changes on Earth, using Sentinel data, aiming at efficient and emergency management services and protection of critical infrastructure. Open weather forecast data are also available from meteorological institutes, adopting the full, free and open access policy of the Copernicus programme. In our tool, these two main sources of weather and satellite data are supported by citizen observations, as they are reporting short messages, images and spatiotemporal information on social media platforms, such as Twitter. Our technologies involve water body detection from satellite data, event detection from the available sources of data and their positioning on a map when spatiotemporal information is available or automatically estimated. Concepts are extracted from satellite or social media images and topics are created by grouping similar Twitter posts. Furthermore, our tool automatically identifies whether an image refers to a flood or not, using computer vision state-of-the-art techniques, based on deep convolutional neural networks. Our tool also offers animation of the user communities to identify authorities in the social network of user interactions. The extracted knowledge is represented in a semantic way that allows for generating notifications and making decisions in an effective and efficient way. These technologies are very useful for water authorities and civil protection agencies in their need to monitor a flood event and to have a holistic view of an area at the preparedness, response and recovery stages.
A call for a paradigm shift from neutrino-driven to jet-driven core-collapse supernova mechanisms
Creators: name: Papish, Oded
name: Nordhaus, Jason
name: Soker, Noam
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Three-dimensional (3D) simulations in recent years have shown severe difficulties producing 10^51 erg explosions of massive stars with neutrino based mechanisms while on the other hand demonstrated the large potential of mechanical effects, such as winds and jets in driving explosions. In this paper we study the typical time-scale and energy for accelerating gas by neutrinos in core-collapse supernovae (CCSNe) and find that under the most extremely favorable (and probably unrealistic) conditions, the energy of the ejected mass can reach at most 5X10^50 erg. More typical conditions yield explosion energies an order-of-magnitude below the observed 10^51 erg explosions. On the other hand, non-spherical effects with directional outflows hold promise to reach the desired explosion energy and beyond. Such directional outflows, which in some simulations are produced by numerical effects of 2D grids, can be attained by angular momentum and jet launching. Our results therefore call for a paradigm shift from neutrino-based explosions to jet-driven explosions for CCSNe.
description: final version; accepted for publication in mnras
Statistical properties of spectra in harmonically trapped spin-orbit coupled systems
Creators: name: Marchukov, O. V.
name: Volosniev, A. G.
name: Fedorov, D. V.
name: Jensen, A. S.
name: Zinner, N. T.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We compute single-particle energy spectra for a one-body hamiltonian consisting of a two-dimensional deformed harmonic oscillator potential, the Rashba spin-orbit coupling and the Zeeman term. To investigate the statistical properties of the obtained spectra as functions of deformation, spin-orbit and Zeeman strengths we examine the distributions of the nearest neighbor spacings. We find that the shapes of these distributions depend strongly on the three potential parameters. We show that the obtained shapes in some cases can be well approximated with the standard Poisson, Brody and Wigner distributions. The Brody and Wigner distributions characterize irregular motion and help identify quantum chaotic systems. We present a special choices of deformation and spin-orbit strengths without the Zeeman term which provide a fair reproduction of the fourth-power repelling Wigner distribution. By adding the Zeeman field we can reproduce a Brody distribution, which is known to describe a transition between the Poisson and linear Wigner distributions.
description: 12 pages, 10 figures, published version
Spatial Coherence Properties of One-Dimensional Exciton-Polariton-Condensates
Creators: name: Fischer, J.
name: Savenko, I. G.
name: Fraser, M. D.
name: Holzinger, S.
name: Brodbeck, S.
name: Kamp, M.
name: Shelykh, I. A.
name: Schneider, C.
name: Höfling, S.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: In this work, we combine a systematic experimental investigation of the power- and temperaturedependent evolution of the spatial coherence function, g(1) (r), in a one-dimensional excitonpolariton channel with a modern microscopic numerical theory based on a stochastic master equation approach. The spatial coherence function g(1) (r) is extracted via high-precision Michelson interferometry, which allows us to demonstrate that in the regime of non-resonant excitation, the dependence g(1) (r) reaches a saturation value with a plateau, determined by the intensity of pump and effective temperature of the crystal lattice. The theory, which was extended to allow for treating incoherent excitation in a stochastic frame, matches the experimental data with good qualitative and quantitative agreement. This allows us to verify the prediction that the decay of the off-diagonal long range order can be almost fully suppressed in one-dimensional condensate systems.
description: 9 Pages, 5 figures
Πρακτικές μείωσης κόστους στις μικρομεσαίες επιχειρήσεις
Creators: name: Γαλιατσάτου, Δάφνη
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2019
Subjects: subject: Τεχνικές μείωσης κόστους

description: Στην μετά κρίσης εποχή, η ύφεση στην οικονομία και κυρίως στον τομέα παραγωγής, έχει οδηγήσει τις περισσότερες από τις μικρομεσαίες επιχειρήσεις στην Ελλάδα να μην μπορούν να ανταποκριθούν στις ανάγκες παραγωγής τους. Άμεσο αποτέλεσμα αυτού είναι η διακοπή της λειτουργίας τους και κατά συνέπεια η μείωση της επιχειρηματικότητας στη χώρα. Για τη συνέχιση της λειτουργίας μιας επιχείρησης, ειδικά μέσα σ’ ένα περιβάλλον όπως το Ελληνικό, που δεν ευνοεί την ανάπτυξη, σημαντικό ρόλο παίζει η σωστή διαχείριση του κόστους λειτουργίας τους, η εφαρμογή διαρθρωτικών μέτρων και ειδικότερα η εύρεση τρόπων μείωσης περιττών εξόδων, με σκοπό τη συνεχή βελτίωση της αποδοτικότητας της επιχείρησης σε όλα τα τμήματα την αύξηση των περιθωρίων κερδοφορίας τους. Στην διπλωματική αυτή, χρησιμοποιώντας ως παράδειγμα μια Ελληνική εταιρεία παραγωγής, θα προσπαθήσουμε να βρούμε λύσεις μείωσης του κόστους κατασκευής και διανομής λούτρινων παιχνιδιών. Η εταιρεία «much», με πολύχρονη πορεία στον χώρο του παιχνιδιού, αποτελεί την μοναδική εταιρεία λούτρινων παιχνιδιών και παιχνιδιών για παιδιά στην Ελλάδα, η οποία παράγει εξ αρχής τα προϊόντα της αποκλειστικά στην Ελλάδα. Γνωστή για την άψογη ποιότητα και την καλαισθησία των προϊόντων της, αποτελεί πρωτοπόρο στην αγορά με μεγάλο μερίδιο σε σχέση με ανταγωνίστριες εισαγωγικές εταιρίες του ίδιου αντικειμένου. Στα επιμέρους κεφάλαια, αναλύονται τα στάδια παραγωγής και λειτουργίας της εν λόγω επιχείρησης, ώστε να εντοπίσουμε τυχόν αστοχίες και δυσλειτουργίες στο καθένα από αυτά, ενώ αναλύονται και οι διαρθρωτικές ενέργειες στις οποίες προέβη η επιχείρηση για τον εξορθολογισμό του κόστους της και την αύξηση των περιθωρίων κερδοφορίας της.
Thermoacoustic instability - a dynamical system and time domain analysis
Creators: name: Sayadi, Taraneh
name: Chenadec, Vincent Le
name: Schmid, Peter
name: Richecoeur, Franck
name: Massot, Marc
Publisher: name: arXiv
Year: 2013
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: This study focuses on the Rijke tube problem, which includes features relevant to the modeling of thermoacoustic coupling in reactive flows: a compact acoustic source, an empirical model for the heat source, and nonlinearities. This thermo-acoustic system features a complex dynamical behavior. In order to synthesize accurate time-series, we tackle this problem from a numerical point-of-view, and start by proposing a dedicated solver designed for dealing with the underlying stiffness, in particular, the retarded time and the discontinuity at the location of the heat source. Stability analysis is performed on the limit of low-amplitude disturbances by means of the projection method proposed by Jarlebring (2008), which alleviates the linearization with respect to the retarded time. The results are then compared to the analytical solution of the undamped system, and to Galerkin projection methods commonly used in this setting. This analysis provides insight into the consequences of the various assumptions and simplifications that justify the use of Galerkin expansions based on the eigenmodes of the unheated resonator. We illustrate that due to the presence of a discontinuity in the spatial domain, the eigenmodes in the heated case, predicted by using Galerkin expansion, show spurious oscillations resulting from the Gibbs phenomenon. By comparing the modes of the linear to that of the nonlinear regime, we are able to illustrate the mean-flow modulation and frequency switching. Finally, time-series in the fully nonlinear regime, where a limit cycle is established, are analyzed and dominant modes are extracted. The analysis of the saturated limit cycles shows the presence of higher frequency modes, which are linearly stable but become significant through nonlinear growth of the signal. This bimodal effect is not captured when the coupling between different frequencies is not accounted for.
description: Submitted to Journal of Fluid Mechanics
Effect of radiation-like solid on CMB anisotropies
Creators: name: Balek, Vladimír
name: Škovran, Matej
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We compute the power in the lowest multipoles of CMB anisotropies in the presence of radiation-like solid, a hypothetical new kind of radiation with nonzero shear modulus. If only the ordinary Sachs-Wolfe effect is taken into account, the shear modulus to energy density ratio must be in absolute value of order $10^{-5}$ or less for the theory to be consistent with observations within cosmic variance. With the integrated Sachs-Wolfe effect switched on, the constraint is relaxed almost by two orders of magnitude.
description: 24 pages, 3 figures
MPEC 2023-E54 : DAILY ORBIT UPDATE (2023 March 10)
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Education-based grant programmes for bottom-up distance learning and project catalysis: Antimicrobial Resistance in Sub-Saharan Africa
Creators: name: Graham, Chris
name: Akligoh, Harry
name: Ori, Joy King
name: Adzaho, Gameli
name: Salekwa, Linda
name: Campbell, Patrick
name: Saba, Courage KS
name: Landrain, Thomas E.
name: Santolini, Marc
Publisher: name: Microbiology Society
Year: 2023
Subjects: Curriculum and pedagogy theory and development
Microbial ecology
Microbiology not elsewhere classified

description: Supporting data for article 'Education-based grant programmes for bottom-up distance learning and project catalysis: Antimicrobial Resistance in Sub-Saharan Africa' in Access Microbiology.
 Review form used to differentiate projects on AMR: AMR Grant Review Form_ Supplementary Materials - Google Forms.pdf
 Microbis location data: AMRlocationdata.gpx
 Form for application to the AMR workshops held July 2021: AMR Workshop Application - Google Forms.pdf
Effect of asphericity in caustic mass estimates of galaxy clusters
Creators: name: Svensmark, Jacob
name: Wojtak, Radoslaw
name: Hansen, Steen H.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The caustic technique for measuring mass profiles of galaxy clusters relies on the assumption of spherical symmetry. When applied to aspherical galaxy clusters, the method yields mass estimates affected by the cluster orientation. Here we employ mock redshift catalogues generated from cosmological simulations to study the effect of clusters intrinsic shape and surrounding filamentary structures on the caustic mass estimates. To this end, we develop a new method for removing perturbations from large-scale structures, modelled as the two-halo term, in a caustic analysis of stacked cluster data. We find that the cluster masses inferred from kinematical data of ~10^14 Msun clusters observed along the major axis are larger than masses from those observed along the minor axis by a factor of 1.7 within the virial radius, increasing to 1.8 within three virial radii. This discrepancy increases by 20% for the most massive clusters. In addition a smaller but still significant mass discrepancy arises when filamentary structures are present near a galaxy cluster. We find that the mean cluster mass from random sightlines is unbiased at all radii and their scatter ranges from 0.14 to 0.17 within one and three virial radii, with a 40% increase for the most massive clusters. We provide tables which estimate the caustic mass bias given observational constraints on the cluster orientation.
description: 19 pages, 9 figures, 6 tables, accepted for publication in MNRAS