cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Many-body localisation implies that eigenvectors are matrix-product states
Creators: name: Friesdorf, M.
name: Werner, A. H.
name: Brown, W.
name: Scholz, V. B.
name: Eisert, J.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The phenomenon of many-body localisation received a lot of attention recently, both for its implications in condensed-matter physics of allowing systems to be an insulator even at non-zero temperature as well as in the context of the foundations of quantum statistical mechanics, providing examples of systems showing the absence of thermalisation following out-of-equilibrium dynamics. In this work, we establish a novel link between dynamical properties - the absence of a group velocity and transport - with entanglement properties of individual eigenvectors. Using Lieb-Robinson bounds and filter functions, we prove rigorously under simple assumptions on the spectrum that if a system shows strong dynamical localisation, all of its many-body eigenvectors have clustering correlations. In one dimension this implies directly an entanglement area law, hence the eigenvectors can be approximated by matrix-product states. We also show this statement for parts of the spectrum, allowing for the existence of a mobility edge above which transport is possible.
description: 13 pages, 4 figures
Chern-Simons vortices and holography
Creators: name: Roychowdhury, Dibakar
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, based on the $ AdS_{4}/CFT_{3} $ duality, we have explored the precise connection between the abelian Chern-Simons (CS) Higgs model in ($ 2+1 $) dimensions to that with its dual gravitational counterpart living in one higher dimension. It has been observed that the $ U(1) $ current computed at the boundary of the $ AdS_{4} $ could be expressed as the local function of the vortex solution that has the remarkable structural similarity to that with the Ginzburg-Landau (GL) type local expression for the current associated with the Maxwell-CS type vortices in ($ 2+1 $) dimensions. In order to explore this duality a bit further we have also computed the coherence length as well as the magnetic penetration depth associated with these vortices. Finally using the knowledge of both the coherence length as well as the magnetic penetration depth we have computed the Ginzburg-Landau coefficient for the Maxwell-CS type vortices in ($ 2+1 $) dimensions.
description: Latex,32 pages, Version to appear in JHEP
Production, characteristics and applications of microbial heparinases
Creators: name: BOYCE, ANGELA
name: WALSH, GARY
Publisher: name: University of Limerick
Year: 2022
Subjects: subject: Chemical sciences
subject: FOS: Chemical sciences

description: Heparinases are enzymes that selectively cleave heparin and heparan sulfate chains, via cleavage of the glycosidic linkage between hexosamines and uronic acids, producing disaccharide and oligosaccharide products. While heparin is well known as an anti-coagulant drug, heparin and heparan sulfate are also involved in biological processes such as inflammation, cancer and angiogenesis and viral and bacterial infections and are of growing interest for their therapeutic potential. Recently, potential roles of heparin and heparan sulfate in relation to COVID-19 infection have been highlighted. The ability of heparinases to selectively cleave heparin chains has been exploited industrially to produce low molecular weight heparin, which has replaced heparin in several clinical applications. Other applications of heparinases include heparin and heparan sulfate structural analysis, neutralisation of heparin in blood and removal of the inhibitory effect of heparin on various enzymes. Heparinases are known to inhibit neovascularization and heparinase III is of interest for treating cancer and inhibiting tumour cell growth. Heparinase activity, first isolated from Pedobacter heparinus, has since been reported from several other microorganisms. Significant progress has been made in the production, characterisation and improvement of microbial heparinases in response to application demands in terms of heparinase yield and purity, which is likely to extend their usefulness in various applications. This review focuses on recent developments in the identification, characterisation and improvement of microbial heparinases and their established and emerging industrial, clinical and therapeutic applications.
Imprisoned insolvent debtors in Leicestershire in the long eighteenth century
Creators: name: Postles, Dave
Publisher: name: Archaeology Data Service
Year: 2023

description: Leicestershire Historian, 58, 55-61
description: In the early nineteenth century, three carceral institutions in Leicester housed debtors. In 1803, 1805, 1807 and 1809, the County Bridewell contained respectively seven, 15, 17 and 17 debtors. In the adjacent County gaol, together with but separate from felons, were incarcerated 18 debtors in 1802, a dozen the following year, eight in 1805, 11 in 1807 and 13 in 1809. In contrast, the Town Gaol provided hospitality for two to five debtors in alternate years between 1803 and 1809.
Getting inflationary models using the deformation method
Creators: name: Rodrigues, Jamilton
name: Souza, Marcos
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper we show that the dynamics associated with slow-roll models of inflation can be investigated through a method called deformation procedure. Using the latter, we explicitly derive an expression linking two slow-roll inflationary potentials, applying the resulting framework to show how to construct an eternal inflation from chaotic inflation, or even, a natural inflation from hilltop inflation, easily.
description: 6 pages, 2 figures
HD 45166: The first magnetic Wolf-Rayet star
Creators: name: Shenar, Tomer
Publisher: name: Zenodo
Year: 2022

description: The mysterious "quasi Wolf-Rayet (qWR)" binary HD 45166 has been the subject of dozens of studies for over a century. It was proposed to consist of a 4Msun helium star with a Wolf-Rayet spectrum orbiting a B7 V star on a 1.6d period, making it the only intermediate-mass helium star known in the Galaxy. The properties of this binary are fully at odds with our understanding of wind-launching physics and binary evolution. However, spectropolarimetry obtained with the ESPaDOnS instrument in February 2022 reveal that the qWR component exhibits the strongest magnetic field ever detected in the massive-star regime, amounting to 43kG. The detection makes this object the first known magnetic Wolf-Rayet star and a prime progenitor of a magnetar. A long-term monitoring campaign further implies that the true orbital period is of the order of tens of years, and not 1.6d. In my talk, I will present our spectroscopic and spectropolarimetric campaign, which reshuffles our understanding of this system. I will highlighting the implications of this object on our understanding of binary evolution and mergers, and conclude with a few ideas regarding the formation of such a unique object and other related objects in our Galaxy.
Non-relativistic Josephson Junction from Holography
Creators: name: Li, Huai-Fan
name: Li, Li
name: Wang, Yong-Qiang
name: Zhang, Hai-Qing
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We construct a Josephson junction in non-relativistic case with a Lifshitz geometry as the dual gravity. We investigate the effect of the Lifshitz scaling in comparison with its relativistic counterpart. The standard sinusoidal relation between the current and the phase difference is found for various Lifshitz scalings characterised by the dynamical critical exponent. We also find the exponential decreasing relation between the condensate of the scalar operator within the barrier at zero current and the width of the weak link, as well as the relation between the critical current and the width. Nevertheless, the coherence lengths obtained from two exponential decreasing relations generically have discrepancies for non-relativistic dual.
description: v3: references added, to appear in JHEP
Effects of Economic Opportunity Loans on Lobster Fishermen in Maine, 1965-67
Creators: name: Bowring, James R.
name: Steward, Donald D.
name: Bird, Ronald
name: Bowring, James R.
name: Steward, Donald D.
name: Bird, Ronald
Publisher: name: Unknown
Year: 1968
Subjects: Agricultural and Food Policy
Community/Rural/Urban Development

description: Excerpts from the report Highlights: Economic Opportunity loans to lobster fishermen o£ Hancock and Washington Counties, Maine, averaged $1,918 in 1965. The funds were used primarily for the purchase or repair of boats and other equipment. Only a small part was used for construction or repairs to buildings. Under the Economic Opportunity Act of 1964, the Farmers Home Administration makes loans to low-income rural families to finance small farm and nonfarm businesses, trades, or services. All lobster fishermen who obtained an EO loan were experienced fishermen. Most were independent fishermen prior to applying for a loan, although some were working for other lobstermen. In the first year after receiving their loans, the borrowers reported a net cash family income averaging $2,927, an increase of $565 above that reported in the year prior to receiving the loan. In addition, they expected further increases averaging $879 in the second year.
John Flower: Topographical Studies in Leicester and Leicestershire
Creators: name: Finn, Neil
Publisher: name: Archaeology Data Service
Year: 2023

description: Leicestershire Historian, 44, 40-46
description: This article considers the historical significance of John Flower's lesser known topographical works for Leicester and Leicestershire, based on recent work on cataloguing the collection of over 200 sketches and watercolours by Flower held at the Record Office for Leicestershire, Leicester and Rutland, alongside other public collections of his artwork.
Study of Centrality Dependence of Kinetic Freeze-out Conditions in Pb + Pb Collisions at Root(sNN)= 2.76 TeV
Creators: name: Uddin, Saeed
name: Bashir, Inam-ul
name: Bhat, Riyaz Ahmed
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The transverse momentum spectra of identified particles at midrapidity in Pb + Pb collisions at Root(sNN) = 2.76 TeV have been studied as a function of collision centrality by using a unified statistical thermal freeze-out model. The calculated results are found to be in good agreement with the experimental data measured by the ALICE experiment at LHC. The model calculations provide the thermal freeze-out conditions in terms of the temperature and collective flow parameters for different particle species. We observe a rise in the thermal freeze-out temperature but a mild decrease in the collective flow velocity parameter from central to peripheral collisions. The model used incorporates the simultaneous effect of the longitudinal as well as transverse hydrodynamic flows. The baryon chemical potential is assumed to be zero (μB ~ 0), a situation expected in the heavy ion collisions at LHC energies due to a high degree of nuclear transparency.
description: 20 Pages, 6 Figures, 10 Tables. arXiv admin note: substantial text overlap with arXiv:1407.6165
Cosmological perturbations in massive bigravity
Creators: name: Lagos, Macarena
name: Ferreira, Pedro G.
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present a comprehensive analysis of classical scalar, vector and tensor cosmological perturbations in ghost-free massive bigravity. In particular, we find the full evolution equations and analytical solutions in a wide range of regimes. We show that there are viable cosmological backgrounds but, as has been found in the literature, these models generally have exponential instabilities in linear perturbation theory. However, it is possible to find stable scalar cosmological perturbations for a very particular choice of parameters. For this stable subclass of models we find that vector and tensor perturbations have growing solutions. We argue that special initial conditions are needed for tensor modes in order to have a viable model.
description: 42 pages, 15 figures. Update: typos corrected and appendix on Higuchi bound
HeFDI Code School: Sustainable Research Software - Scientific Software Development is not a Jenga game!
Creators: name: Jan Linxweiler
name: Sven Marcus
name: Sören Peters
Publisher: name: Zenodo
Year: 2023
Subjects: RSE
Software Engineering
SOLID
OOP

description: Scientific software is in many disciplines crucial for understanding and reusing research data and a cornerstone for reproducibility of research results. The HeFDI Code School adresses the need of especially early career researchers on learning how to create good scientific software and increase the quality of their code for better reusability and sustainability.
Together with the colleagues from Suresoft project and NFDI4Ing we offer a series of four workshops.
Participants of these workshops will learn

methods and techniques to increase the quality of their code,
how to produce understandable and therefore reusable code,
and to increase the sustainability of scientific software.
Workshop - May 12 & Oct 27 - Scientific Software Development is not a Jenga game!
Scientific software is often hard to maintain and reuse. A major reason for the instability of software is that it is subject to continuous change. This is especially true for software in the scientific context, since the scientific discourse is open-ended. Change has caused difficulties for scientific software developers from the very beginning, and it continues to do so. In parallel, the software engineering community has produced numerous developments that we as research software developers can take advantage of to significantly support our work. This workshop is an introduction on how to bridge the gap between both worlds and introduces practices, methods and principles to develop maintainable software and to make the software development process sustainable.
Black holes as particle accelerators: a brief review
Creators: name: Harada, Tomohiro
name: Kimura, Masashi
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Rapidly rotating Kerr black holes can accelerate particles to arbitrarily high energy if the angular momentum of the particle is fine-tuned to some critical value. This phenomenon is robust as it is founded on the basic properties of geodesic orbits around a near-extremal Kerr black hole. On the other hand, the maximum energy of the acceleration is subjected to several physical effects. There is convincing evidence that the particle acceleration to arbitrarily high energy is one of the universal properties of general near-extremal black holes. We also discuss gravitational particle acceleration in more general context. This article is intended to provide a pedagogical introduction to and a brief overview of this topic for non-specialists.
description: 26 pages, 6 figures, accepted for publication in Classical and Quantum Gravity as a Topical Review, minor correction
Coupled wake boundary layer model of wind-farms
Creators: name: Stevens, Richard J. A. M.
name: Gayme, Dennice F.
name: Meneveau, Charles
Publisher: name: arXiv
Year: 2014
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We present and test the coupled wake boundary layer (CWBL) model that describes the distribution of the power output in a wind-farm. The model couples the traditional, industry-standard wake model approach with a "top-down" model for the overall wind-farm boundary layer structure. This wake model captures the effect of turbine positioning, while the "top-down" portion of the model adds the interactions between the wind-turbine wakes and the atmospheric boundary layer. Each portion of the model requires specification of a parameter that is not known a-priori. For the wake model, the wake expansion coefficient is required, while the "top-down" model requires an effective spanwise turbine spacing within which the model's momentum balance is relevant. The wake expansion coefficient is obtained by matching the predicted mean velocity at the turbine from both approaches, while the effective spanwise turbine spacing depends on turbine positioning and thus can be determined from the wake model. Coupling of the constitutive components of the CWBL model is achieved by iterating these parameters until convergence is reached. We illustrate the performance of the model by applying it to both developing wind-farms including entrance effects and to fully developed (deep-array) conditions. Comparisons of the CWBL model predictions with results from a suite of large eddy simulations (LES) shows that the model closely represents the results obtained in these high-fidelity numerical simulations. A comparison with measured power degradation at the Horns Rev and Nysted wind-farms shows that the model can also be successfully applied to real wind-farms.
description: 25 pages, 21 figures, submitted to Journal of Renewable and Sustainable Energy on July 18, 2014
Causal Structures in Gauss-Bonnet gravity
Creators: name: Izumi, Keisuke
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We analyze causal structures in Gauss-Bonnet gravity. It is known that Gauss-Bonnet gravity potentially has superluminal propagation of gravitons due to its noncanonical kinetic terms. In a theory with superluminal modes, an analysis of causality based on null curves makes no sense, and thus, we need to analyze them in a different way. In this paper, using the method of the characteristics, we analyze the causal structure in Gauss-Bonnet gravity. We have the result that, on a Killing horizon, gravitons can propagate in the null direction tangent to the Killing horizon. Therefore, a Killing horizon can be a causal edge as in the case of general relativity, i.e. a Killing horizon is the "event horizon" in the sense of causality. We also analyze causal structures on nonstationary solutions with $(D-2)$-dimensional maximal symmetry, including spherically symmetric and flat spaces. If the geometrical null energy condition, $R_{AB}N^AN^B \ge 0$ for any null vector $N^A$, is satisfied, the radial velocity of gravitons must be less than or equal to that of light. However, if the geometrical null energy condition is violated, gravitons can propagate faster than light. Hence, on an evaporating black hole where the geometrical null energy condition is expected not to hold, classical gravitons can escape from the "black hole" defined with null curves. That is, the causal structures become nontrivial. It may be one of the possible solutions for the information loss paradox of evaporating black holes.
description: Version accepted by PRD (v2): 11pages, 1 figure
HeFDI Code School: Sustainable Research Software - Scientific Software Development (Day 1)
Creators: name: Linxweiler, Jan
name: Marcus, Sven
name: Peters, Sören
Publisher: name: Zenodo
Year: 2023
Subjects: RSE, Software Engineering, SOLID, OOP

description: Scientific software is in many disciplines crucial for understanding and reusing research data and a cornerstone for reproducibility of research results. The HeFDI Code School adresses the need of especially early career researchers on learning how to create good scientific software and increase the quality of their code for better reusability and sustainability. Together with the colleagues from Suresoft project and NFDI4Ing we offer a series of four workshops. Participants of these workshops will learn methods and techniques to increase the quality of their code, how to produce understandable and therefore reusable code, and to increase the sustainability of scientific software. Workshop - May 12 - Scientific Software Development is not a Jenga game! Scientific software is often hard to maintain and reuse. A major reason for the instability of software is that it is subject to continuous change. This is especially true for software in the scientific context, since the scientific discourse is open-ended. Change has caused difficulties for scientific software developers from the very beginning, and it continues to do so. In parallel, the software engineering community has produced numerous developments that we as research software developers can take advantage of to significantly support our work. This workshop is an introduction on how to bridge the gap between both worlds and introduces practices, methods and principles to develop maintainable software and to make the software development process sustainable.
Identification techniques for highly boosted W bosons that decay into hadrons
Creators: name: CMS Collaboration
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: In searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMS detector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.
description: Replaced with published version. Added journal reference and DOI
The Structure of Fluid Milk Markets: Two Decades of Change
Creators: name: Manchester, Alden C.
name: Manchester, Alden C.
Publisher: name: Unknown
Year: 1968
Subjects: subject: Agricultural and Food Policy
subject: Industrial Organization
subject: Marketing
subject: FOS: Economics and business

description: Excerpt from the report Introduction: Around the turn of the century when fluid milk markets began to assume their present form, city markets were highly local in character. Literally hundreds of fluid milk distributors operated in large city markets. But, even at that time, a few large dealers did most of the business. Since then, their numbers have been drastically reduced by a series of technological changes and shifts in the economic environment. This study concentrates on the postwar changes in numbers of plants and firms in the fluid milk business and in their market shares, to provide a better understanding of the economic processes that are taking place. This recent history can be understood only in relation to the developments which preceded it.
Yang-Mills gauge fields conserving the symmetry algebra of the Dirac equation in a homogeneous space
Creators: name: Breev, A. I.
name: Shapovalov, A. V.
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences
subject: 43A85

description: We consider the Dirac equation with an external Yang-Mills gauge field in a homogeneous space with an invariant metric. The Yang-Mills fields for which the motion group of the space serves as the symmetry group for the Dirac equation are found by comparison of the Dirac equation with an invariant matrix differential operator of the first order. General constructions are illustrated by the example of de Sitter space. The eigenfunctions and the corresponding eigenvalues for the Dirac equation are obtained in the space $\mathbb{R}^2\times \mathbb{S}^2$ by a noncommutative integration method.
description: 21 pages
Understanding the charmed states recently observed by the LHCb and BaBar Collaborations in the quark model
Creators: name: Lü, Qi-Fang
name: Li, De-Min
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Comparing the expected spectroscopy in the relativistic quark model and the predicted strong decays in the $^3P_0$ model employing the realistic wave functions from the relativistic quark model with the measured properties of the LHCb and BaBar charmed states, we find that the masses and strong decays of these charmed states can be reasonably explained in the conventional $q\bar{q}$ picture, and therefore suggest that the $D(2550)$/$D_J(2580)$, $D^*(2600)$/$D^*_J(2650)$, $D(2750)$/$D_J(2740)$, $D^*(2760)$/$D^*_J(2760)$, $D_J(3000)$, and $D^*_J(3000)$ can be identified as the $D(2^1S_0)$, $D(2^3S_1)$, $D^\prime_2(1D)$, $D(1^3D_3)$, $D(3^1S_0)$, and $D(1^3F_4)$, respectively.
description: 20 pages, version accepted by Phys. Rev. D
The Nonequilibrium Many-Body Problem as a paradigm for extreme data science
Creators: name: Freericks, J. K.
name: Nikolic, B. K.
name: Frieder, O.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Complexity (cs.CC)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Generating big data pervades much of physics. But some problems, which we call extreme data problems, are too large to be treated within big data science. The nonequilibrium quantum many-body problem on a lattice is just such a problem, where the Hilbert space grows exponentially with system size and rapidly becomes too large to fit on any computer (and can be effectively thought of as an infinite-sized data set). Nevertheless, much progress has been made with computational methods on this problem, which serve as a paradigm for how one can approach and attack extreme data problems. In addition, viewing these physics problems from a computer-science perspective leads to new approaches that can be tried to solve them more accurately and for longer times. We review a number of these different ideas here.
description: 33 pages, 7 figures, invited review for Int. J. Mod. Phys. B; published version with additional references
Mammalian cochlea as a physics guided evolution-optimized hearing sensor
Creators: name: Lorimer, Tom
name: Gomez, Florian
name: Stoop, Ruedi
Publisher: name: arXiv
Year: 2014
Subjects: subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: Neurons and Cognition (q-bio.NC)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Nonlinear physics plays an essential role in hearing, from sound signal generation to sound sensing to the processing of complex sound environments. We demonstrate that the evolution of the biological hearing sensors demonstrates a dramatic reduction in the solution space available for hearing sensors due to nonlinear physics principles. More specifically, our analysis hints at that the differences between amniotic lineages hearing, could be recast into a scaleable and a non-scaleable arrangement of nonlinear sound detectors. The scalable solution employed in mammals, as the most advanced design, provides a natural context that demands the ultimate characterization of complex sounds through pitch.
Contribution of evanescent waves to the effective medium of disordered waveguides
Creators: name: Yépez, Miztli
name: Jose, Saenz Juan
Publisher: name: arXiv
Year: 2014
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We consider a wave propagating through a thin disordered slab inside a wire or waveguide of finite width. In the dense weak scattering limit, the statistics for the complex reflection and transmission coefficients (the coherent field) is found to depend dramatically on the contribution of evanescent modes or closed channels, leading to an effective refractive index whose real part is quite sensitive to the closed channels inclusion. In contrast, evanescent modes play no role in the statistical average of transmittances and reflectances. The theoretical predictions, based on the perturbative Born series expansion, are in excellent agreement with numerical simulations in disordered wires.
description: 11 Figures. Accepted for publication in Europhysics Letters
Quasiconvexity at the boundary and the nucleation of austenite
Creators: name: Ball, John
name: Koumatos, Konstantinos
Publisher: name: arXiv
Year: 2014
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: Motivated by experimental observations of H. Seiner et al., we study the nucleation of austenite in a single crystal of a CuAlNi shape-memory alloy stabilized as a single variant of martensite. In the experiments the nucleation process was induced by localized heating and it was observed that, regardless of where the localized heating was applied, the nucleation points were always located at one of the corners of the sample - a rectangular parallelepiped in the austenite. Using a simplified nonlinear elasticity model, we propose an explanation for the location of the nucleation points by showing that the martensite is a local minimizer of the energy with respect to localized variations in the interior, on faces and edges of the sample, but not at some corners, where a localized microstructure, involving austenite and a simple laminate of martensite, can lower the energy. The result for the interior, faces and edges is established by showing that the free-energy function satisfies a set of quasiconvexity conditions at the stabilized variant in the interior, faces and edges, respectively, provided the specimen is suitably cut.
description: 53 pages, to appear at ARMA
PP-waves with Torsion - a Metric-affine Model for the Massless Neutrino
Creators: name: Pasic, Vedad
name: Barakovic, Elvis
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: In this paper we deal with quadratic metric-affine gravity, which we briefly introduce, explain and give historical and physical reasons for using this particular theory of gravity. Further, we introduce a generalisation of well known spacetimes, namely pp-waves. A classical pp-wave is a 4-dimensional Lorentzian spacetime, which admits a nonvanishing parallel spinor field; here the connection is assumed to be Levi-Civita. This definition was generalised in our previous work to metric compatible spacetimes with torsion and used to construct new explicit vacuum solutions of quadratic metric-affine gravity, namely generalised pp-waves of parallel Ricci curvature. The physical interpretation of these solutions we propose in this article is that they represent a conformally invariant metric-affine model for a massless elementary particle. We give a comparison with the classical model describing the interaction of gravitational and massless neutrino fields, namely Einstein-Weyl theory and construct pp-wave type solutions of this theory. We point out that generalised pp-waves of parallel Ricci curvature are very similar to pp-wave type solutions of the Einstein-Weyl model and therefore propose that our generalised pp-waves of parallel Ricci curvature represent a metric-affine model for the massless neutrino.
description: 24 pages. Corrected two references. The final publication is available at springerlink.com. arXiv admin note: text overlap with arXiv:gr-qc/0505157; and text overlap with arXiv:gr-qc/0304028, arXiv:gr-qc/9402012 by other authors
HeFDI Code School: Sustainable Research Software - Scientific Software Development is not a Jenga game!
Creators: name: Linxweiler, Jan
name: Marcus, Sven
name: Peters, Sören
Publisher: name: Zenodo
Year: 2023
Subjects: RSE
Software Engineering
SOLID
OOP

description: Scientific software is in many disciplines crucial for understanding and reusing research data and a cornerstone for reproducibility of research results. The HeFDI Code School adresses the need of especially early career researchers on learning how to create good scientific software and increase the quality of their code for better reusability and sustainability. Together with the colleagues from Suresoft project and NFDI4Ing we offer a series of four workshops. Participants of these workshops will learn methods and techniques to increase the quality of their code, how to produce understandable and therefore reusable code, and to increase the sustainability of scientific software. Workshop - May 12 - Scientific Software Development is not a Jenga game! Scientific software is often hard to maintain and reuse. A major reason for the instability of software is that it is subject to continuous change. This is especially true for software in the scientific context, since the scientific discourse is open-ended. Change has caused difficulties for scientific software developers from the very beginning, and it continues to do so. In parallel, the software engineering community has produced numerous developments that we as research software developers can take advantage of to significantly support our work. This workshop is an introduction on how to bridge the gap between both worlds and introduces practices, methods and principles to develop maintainable software and to make the software development process sustainable.
Quantum bright solitons in the Bose-Hubbard model with site-dependent repulsive interactions
Creators: name: Barbiero, L.
name: Malomed, B. A.
name: Salasnich, L.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We introduce a one-dimensional (1D) spatially inhomogeneous Bose-Hubbard model (BHM) with the strength of the onsite repulsive interactions growing, with the discrete coordinate $z_{j}$, as $|z_{j}|^{α}$ with $α>0$. Recently, the analysis of the mean-field (MF) counterpart of this system has demonstrated self-trapping of robust unstaggered discrete solitons, under condition $α>1$. Using the numerically implemented method of the density matrix renormalization group (DMRG), we demonstrate that, in a certain range of interaction, the BHM also self-traps, in the ground state, into a soliton-like configuration, at $α>1$, and remains weakly localized at $α<1$. An essential quantum feature is a residual density in the background surrounding the soliton-like peak in the BHM ground state, while in the MF limit the finite-density background is absent. Very strong onsite repulsion eventually destroys soliton-like states, and, for integer densities, the system enters the Mott phase with a spatially uniform density
description: Phys. Rev. A, in press
Activism and identity in the Somali community
Creators: name: Nimmons, Elizabeth A.
Publisher: name: The University of Texas at Austin
Year: 2023
Subjects: Activism
Identity
Somali
Black Lives Matter
Racial justice
Social movement
Muslim

description: In the wake of George Floyd’s murder at the hands of the Minneapolis Police Department, the Minneapolis-St. Paul metropolitan community quickly mobilized for racial justice. Critical to this uprising was the role of the Somali community in the Twin Cities. Once conscious of distancing themselves from Black Americans, Somalis began taking an active role in advancing the Black Lives Matter movement in Minnesota. This dissertation is a study of the connections between identity and activism in the Somali community following the rise of Black Lives Matter, and particularly, in the wake of the murder of George Floyd. The project considers how race, ethnicity, religion, nationality, and generation intersect to shape the experiences of Somalis in the Twin Cities and how these various identities impact participation in activist causes. I find that that Somali identity is kaleidoscopic in nature, and while others (e.g., law enforcement) may perceive Somalis in a relational way, Somalis themselves understand their own identities to be constantly multifaceted and intersectional. Furthermore, Somalis do not reject their Blackness, but rather openly acknowledge the role of race in their own lives and those of their children. Critically, Somalis are keenly aware of the ways their race puts them at risk of violence from law enforcement. Data also show that while young Somali-American adults may not explicitly embrace an American identity, they embody this identity socio-politically, as evidenced by their inclusion in what sociologist Ruth Milkman calls the New Political Generation. In addition, my analyses point to intersections of identity and activism, particularly regarding Somalis’ Black and Muslim identities and the ways they influence ideological affinity with Black Lives Matter. By using the case of Somalis to examine activism through the lens of identity, I expand what we know about immigrant participation in social movements and bring new voices to the struggle for racial justice.
Friction in Gravitational Waves: a test for early-time modified gravity
Creators: name: Pettorino, Valeria
name: Amendola, Luca
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Modified gravity theories predict in general a non standard equation for the propagation of gravitational waves. Here we discuss the impact of modified friction and speed of tensor modes on cosmic microwave polarization B modes. We show that the non standard friction term, parametrized by $α_{M}$, is degenerate with the tensor-to-scalar ratio $r$, so that small values of $r$ can be compensated by negative constant values of $α_M$. We quantify this degeneracy and its dependence on the epoch at which $α_{M}$ is different from the standard, zero, value and on the speed of gravitational waves $c_{T}$. In the particular case of scalar-tensor theories, $α_{M}$ is constant and strongly constrained by background and scalar perturbations, $0\le α_{M}< 0.01$ and the degeneracy with $r$ is removed. In more general cases however such tight bounds are weakened and the B modes can provide useful constraints on early-time modified gravity.
description: Minor changes after published version. One new figure
CYBER-SECURITY EFFICACY AND FINANCIAL PERFORMANCE OF FINTECH COMPANIES IN NIGERIA
Creators: name: IMOH, JULIA IFEYINWA
name: EMENGINI, EMEKA STEVE
name: IMOH, OSITA JUSTIN
Publisher: name: Zenodo
Year: 2023
Subjects: Cybersecurity Efficacy, Financial Performance, Fintech Companies, Nigeria.

description:  
Abstract
Against the backdrop of producing empirical evidence that supports a rewarding return on investments in cyber security efficacy, this study investigated the degree of influence cyber security efficacy exerts on financial performance using primary source for data collection. Fintech companies in Nigeria were taken as the study population. Cyber security efficacy was operationalized in terms of access restriction capacity (ARC), attack resistance capacity (ATC) and self-preservation capacity (SPC), while return on asset (ROA) was used as proxies of financial performance. Top management support was utilized as the contextual factor in relating cyber security efficacy to financial performance. Multiple linear regression technique was used as the principal too of statistical analysis while Pearson's Product Moment Correlation was used in supporting role. On the final analysis, it was found that analysis produced evidence that access restrictions capacity of digital products of Fintech companies in Nigeria significantly exerts positive influence on their return on assets. Also, analysis showed that attack resistance capacity of digital products of Fintech companies in Nigeria exerts significant positive influence on their return on assets. It was also found that self-preservation capacity of digital products of Fintech companies in Nigeria exerts significant positive influence on their return on assets. Lastly, it was found that top management support level at Fintech companies in Nigeria significantly moderates the degree of relationship between their cyber security efficacy and return on assets. It is therefore concluded that if the full potentials of online payments, e-commerce and other digital product markets have to be realised, then it is incumbent on Fintech companies to make significant amount of investments that have direct bearing on the efficacy of cyber security. Based on the results and conclusions, we recommend that Fintech companies should improve on the use of multiple layer system of user ID authentication that includes bio-metric means, among others.
Nonlinear spin-thermoelectric transport in two-dimensional topological insulators
Creators: name: Hwang, Sun-Yong
name: Lopez, Rosa
name: Lee, Minchul
name: Sanchez, David
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We consider spin-polarized transport in a quantum spin Hall antidot system coupled to normal leads. Due to the helical nature of the conducting edge states, the screening potential at the dot region becomes spin dependent without external magnetic fields nor ferromagnetic contacts. Therefore, the electric current due to voltage or temperature differences becomes spin polarized, its degree of polarization being tuned with the dot level position or the base temperature. This spin-filter effect arises in the nonlinear transport regime only and has a purely interaction origin. Likewise, we find a spin polarization of the heat current which is asymmetric with respect to the bias direction. Interestingly, our results show that a pure spin current can be generated by thermoelectric means: when a temperature gradient is applied, the created thermovoltage (Seebeck effect) induces a spin-polarized current for vanishingly small charge current. An analogous effect can be observed for the heat transport: a pure spin heat flows in response to a voltage shift even if the thermal current is zero.
description: 10 pages, 7 figures
Anomalous Diffusion of Self-Propelled Particles in Directed Random Environments
Creators: name: Shaebani, M. Reza
name: Sadjadi, Zeinab
name: Sokolov, Igor M.
name: Rieger, Heiko
name: Santen, Ludger
Publisher: name: arXiv
Year: 2014
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We theoretically study the transport properties of self-propelled particles on complex structures, such as motor proteins on filament networks. A general master equation formalism is developed to investigate the persistent motion of individual random walkers, which enables us to identify the contributions of key parameters: the motor processivity, and the anisotropy and heterogeneity of the underlying network. We prove the existence of different dynamical regimes of anomalous motion, and that the crossover times between these regimes as well as the asymptotic diffusion coefficient can be increased by several orders of magnitude within biologically relevant control parameter ranges. In terms of motion in continuous space, the interplay between stepping strategy and persistency of the walker is established as a source of anomalous diffusion at short and intermediate time scales.
description: 5 pages, 5 figures
Double Field Theory on Group Manifolds
Creators: name: Blumenhagen, Ralph
name: Hassler, Falk
name: Lust, Dieter
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A new version of double field theory (DFT) is derived for the exactly solvable background of an in general left-right asymmetric WZW model in the large level limit. This generalizes the original DFT that was derived via expanding closed string field theory on a torus up to cubic order. The action and gauge transformations are derived for fluctuations around the generalized group manifold background up to cubic order, revealing the appearance of a generalized Lie derivative and a corresponding C-bracket upon invoking a new version of the strong constraint. In all these quantities a background dependent covariant derivative appears reducing to the partial derivative for a toroidal background. This approach sheds some new light on the conceptual status of DFT, its background (in-)dependence and the up-lift of non-geometric Scherk-Schwarz reductions.
description: 43 pages, no figures, references added, typos corrected
How to read probability distributions as statements about process
Creators: name: Frank, Steven A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Other Statistics (stat.OT)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Probability (math.PR)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: FOS: Biological sciences

description: Probability distributions can be read as simple expressions of information. Each continuous probability distribution describes how information changes with magnitude. Once one learns to read a probability distribution as a measurement scale of information, opportunities arise to understand the processes that generate the commonly observed patterns. Probability expressions may be parsed into four components: the dissipation of all information, except the preservation of average values, taken over the measurement scale that relates changes in observed values to changes in information, and the transformation from the underlying scale on which information dissipates to alternative scales on which probability pattern may be expressed. Information invariances set the commonly observed measurement scales and the relations between them. In particular, a measurement scale for information is defined by its invariance to specific transformations of underlying values into measurable outputs. Essentially all common distributions can be understood within this simple framework of information invariance and measurement scale.
description: v2: added table of contents, adjusted section numbers v3: minor editing, updated reference