cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
LOCUS: A Multi-Sensor Lidar-Centric Solution for High-Precision Odometry and 3D Mapping in Real-Time
Creators: name: Palieri, M.
name: Morrell, B.
name: Thakur, A
name: Ebadi, K.
name: Nash, J.
name: Chatterjee, A.
name: Kanellakis, C.
name: Carlone, L.
name: Guaragnella, C.
name: Agha-mohammadi, A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: A reliable odometry source is a prerequisite to enable complex autonomy behaviour in next-generation robots operating in extreme environments. In this work, we present a high-precision lidar odometry system to achieve robust and real-time operation under challenging perceptual conditions. LOCUS (Lidar Odometry for Consistent operation in Uncertain Settings), provides an accurate multi-stage scan matching unit equipped with an health-aware sensor integration module for seamless fusion of additional sensing modalities. We evaluate the performance of the proposed system against state-of-the-art techniques in perceptually challenging environments, and demonstrate top-class localization accuracy along with substantial improvements in robustness to sensor failures. We then demonstrate real-time performance of LOCUS on various types of robotic mobility platforms involved in the autonomous exploration of the Satsop power plant in Elma, WA where the proposed system was a key element of the CoSTAR team's solution that won first place in the Urban Circuit of the DARPA Subterranean Challenge.
description: Accepted for publication at IEEE Robotics and Automation Letters, 2020
title: Dagstuhl Reports, Table of Contents, Volume 8, Issue 8, 2018
Creators: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2019
Subjects: subject: Table of Contents
subject: Frontmatter

description: Dagstuhl Reports, Table of Contents, Volume 8, Issue 8, 2018
description: Dagstuhl Reports, Volume 8, Issue 8, pages i-ii
Stakeholders' perception on performance outcomes of student development program based on Thai qualifications framework for higher education at Boromarajonani College of Nursing, Sanpasitthiprasong: A comparative study between academic year 2015 and 2016.
Creators: name: Sakonsupa Apichutboonchock
name: Warunee Nadoon
Publisher: name: Text and Journal Publication
Year: 2019
Subjects: Outcomes
developing
Thai qualifications framework higher education
nursing

description: Vajira Medical Journal, 63, 2, -
title: Short-Run Dynamics in a Search-Theoretic Model of Monetary Exchange
Creators: name: Chiu, Jonathan
name: Molico, Miguel
Publisher: name: Bank of Canada
Year: 2020

description: It is a common belief that monetary policy has persistent short-run effects on the economy. However, the channels through which it operates are still not fully understood.

We study the effects of "helicopter money"—distributing money in a uniform fashion—in an economy where agents have heterogeneous money holdings and are subject to random liquidity needs.

We show that an expansionary monetary policy has persistently positive effects on economic output and social welfare. The policy reallocates purchasing power from the rich to the poor through a “redistributive channel.”  Furthermore, we find that the effects of positive and negative monetary interventions are typically asymmetric.
description: Il est communément admis que la politique monétaire a des effets à court terme persistants sur l’économie. Toutefois, les canaux par lesquels se transmettent les mesures de politique monétaire sont encore mal compris.

Nous étudions l’incidence de « l’hélicoptère monétaire » – qui consiste à distribuer de l’argent de façon uniforme – dans une économie où la détention d’argent est hétérogène et où les agents sont soumis à des besoins aléatoires en liquidités.

Nous montrons qu’une politique monétaire expansionniste a des retombées positives durables sur la production économique et le bien-être collectif. Elle engendre un transfert de pouvoir d’achat des personnes aisées aux personnes peu fortunées par la voie d’un « canal de redistribution ». De plus, nous constatons que les chocs de politique monétaire positifs et négatifs ont généralement des effets asymétriques.
The volume and time comparison principle and transition probability estimates for random walks
Creators: name: Telcs, Andras
Publisher: name: arXiv
Year: 2008
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: This paper presents necessary and sufficient conditions for on- and off-diagonal transition probability estimates for random walks on weighted graphs. On the integer lattice and on may fractal type graphs both the volume of a ball and the mean exit time from a ball is independent of the centre, uniform in space. Here the upper estimate is given without such restriction and two-sided estimate is given if uniformity in the space assumed only for the mean exit time.
Excitation spectra of quantum matter without quasiparticles II: random $t$-$J$ models
Creators: name: Tikhanovskaya, Maria
name: Guo, Haoyu
name: Sachdev, Subir
name: Tarnopolsky, Grigory
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present numerical solutions of the spectral functions of $t$-$J$ models with random and all-to-all exchange and global SU($M$) spin rotation symmetry. The solutions are obtained from the saddle-point equations of the large volume limit, followed by the large $M$ limit. These saddle point equations involve Green's functions for fractionalized spinons and holons carrying emergent U(1) gauge charges, obeying relations similar to those of the Sachdev-Ye-Kitaev (SYK) models. The low frequency spectral functions are compared with an analytic analysis of the operator scaling dimensions, with good agreement. We also compute the low frequency and temperature behavior of gauge-invariant observables: the electron Green's function, the local spin susceptibility and the optical conductivity; along with the temperature dependence of the d.c. resistivity. The time reparameterization soft mode (equivalent to the boundary graviton in holographically dual models of two-dimensional quantum gravity) makes important contributions to all observables, and provides a linear-in-temperature contribution to the d.c. resistivity.
description: 40 pages, 15 figures
A 2MASS All-Sky View of the Sagittarius Dwarf Galaxy: Variation of the Metallicity Distribution Function Along the Sagittarius Stream
Creators: name: Chou, Mei-Yin
name: Majewski, Steven R.
name: Cunha, Katia
name: Smith, Verne V.
name: Patterson, Richard J.
name: Martinez-Delgado, David
name: Law, David R.
name: Crane, Jeffrey D.
name: Munoz, Ricardo R.
name: Lopez, Ramon Garcia
name: Geisler, Doug
name: Skrutskie, Michael F.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present reliable measurements of the metallicity distribution function (MDF) at different points along the tidal stream of the Sagittarius (Sgr) dwarf spheroidal (dSph) galaxy, based on high resolution, echelle spectroscopy of candidate M giant members of the Sgr system. The Sgr MDF is found to evolve significantly from a median [Fe/H] ~-0.4 in the core to ~-1.1 dex over a Sgr leading arm length representing ~2.5-3.0 Gyr of dynamical (i.e. tidal stripping) age. This is direct evidence that there can be significant chemical differences between current dSph satellites and the bulk of the stars they have contributed to the halo. Our results suggest that Sgr experienced a significant change in binding energy over the past several Gyr, which has substantially decreased its tidal boundary across a radial range over which there must have been a significant metallicity gradient in the progenitor galaxy. By accounting for MDF variation along the debris arms, we approximate the MDF Sgr would have had several Gyr ago. We also analyze the MDF of a moving group of M giants we previously discovered towards the North Galactic Cap having opposite radial velocities to the infalling Sgr leading arm stars there and propose that most of these represent Sgr trailing arm stars overlapping the Sgr leading arm in this part of the sky. If so, these trailing arm stars further demonstrate the strong MDF evolution within the Sgr stream.
description: The new version is a much-expanded version moved from ApJL to ApJ and will appear in Dec. 1 edition
Interrelation of elasticity and thermal bath in nanotube cantilevers
Creators: name: Tepsic, S.
name: Gruber, G.
name: Moller, C. B.
name: Magen, C.
name: Belardinelli, P.
name: Hernadez, E. R.
name: Alijani, F.
name: Verlot, P.
name: Bachtold, A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report the first study on the thermal behaviour of the stiffness of individual carbon nanotubes, which is achieved by measuring the resonance frequency of their fundamental mechanical bending modes. We observe a reduction of the Young's modulus over a large temperature range with a slope $-(173\pm 65)$ ppm/K in its relative shift. These findings are reproduced by two different theoretical models based on the thermal dynamics of the lattice. These results reveal how the measured fundamental bending modes depend on the phonons in the nanotube via the Young's modulus. An alternative description based on the coupling between the measured mechanical modes and the phonon thermal bath in the Akhiezer limit is discussed.
Dual Orbital Degeneracy Lifting in a Strongly Correlated Electron System
Creators: name: Koch, R. J.
name: Sinclair, R.
name: McDonnell, M. T.
name: Yu, R.
name: Abeykoon, M.
name: Tucker, M. G.
name: Tsvelik, A. M.
name: Billinge, S. J. L.
name: Zhou, H. D.
name: Yin, W. -G.
name: Bozin, E. S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The local structure of NaTiSi$_{2}$O$_{6}$ is examined across its Ti-dimerization orbital-assisted Peierls transition at 210 K. An atomic pair distribution function approach evidences local symmetry breaking preexisting far above the transition. The analysis unravels that on warming the dimers evolve into a short range orbital degeneracy lifted (ODL) state of dual orbital character, persisting up to at least 490 K. The ODL state is correlated over the length scale spanning $\sim$6 sites of the Ti zigzag chains. Results imply that the ODL phenomenology extends to strongly correlated electron systems.
description: 7 pages, 5 figures
Awareness of Obstetric Danger Signs and Associated Factors among Pregnant Women Attending Antenatal care at the Faculty of Medicine Vajira Hospital
Creators: name: Kasemsis Kaewkiattikun
name: Tunlanan Lekbornvornwong
Publisher: name: Text and Journal Publication
Year: 2019
Subjects: pregnancy
danger signs
awareness
antenatal care

description: Vajira Medical Journal, 63, 2, -
Hirtodrosophila duncani
Creators: name: Grimaldi, David A.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Drosophilidae
Hirtodrosophila
Hirtodrosophila duncani

description: Hirtodrosophila duncani (Sturtevant)
Figures 4, 15C, 20, 21, 41
description: Published as part of Grimaldi, David A., 2018, Hirtodrosophila Of North America (Diptera: Drosophilidae), pp. 1 in Bulletin of the American Museum of Natural History 2018 (421) on page 1, DOI: 10.1206/0003-0090-421.1.1, http://zenodo.org/record/10687866
title: Earnings Dynamics and Intergenerational Transmission of Skill
Creators: name: Lochner, Lance
name: Park, Youngmin
Publisher: name: Bank of Canada
Year: 2020

description: Intergenerational mobility refers to any change in the social and economic status between generations. It is widely considered a critical component of social justice and an indicator of economic efficiency.

A popular way of measuring intergenerational mobility is to assess the persistence of earnings across generations. However, this measure does not necessarily reflect intergenerational mobility in long-run economic status. This is because earnings vary from one year to another due to short-term factors unrelated to intergenerational mobility. To address this issue, we estimate the intergenerational persistence in permanent earnings, or “skill.”

Our estimates, based on Canadian tax data covering 37 years, show that the intergenerational persistence in skill is two to three times higher than that in earnings. This implies that Canada is a less mobile country than previously thought. Our analysis also sheds new light on how earnings and skill vary over the life cycle as well as across generations and on the relationship between inequality and intergenerational mobility.
description: La mobilité intergénérationnelle désigne les changements au statut social et économique au fil des générations. Elle est largement considérée comme une composante essentielle de la justice sociale et comme un indicateur de l’efficacité économique.

L’une des façons courantes de mesurer la mobilité intergénérationnelle est d’évaluer la persistance des revenus d’une génération à l’autre. Cependant, cette mesure ne montre pas nécessairement la mobilité intergénérationnelle par rapport au statut économique à long terme. C’est que les revenus varient d’une année à l’autre en raison de facteurs à court terme sans lien avec la mobilité intergénérationnelle. Pour tenir compte de ce phénomène, nous estimons la persistance intergénérationnelle des revenus permanents, c’est-à-dire de la « compétence ».

Nos estimations, qui reposent sur des données fiscales canadiennes s’étendant sur une période de 37 ans, montrent que la persistance intergénérationnelle de la compétence est deux à trois fois plus élevée que celle des revenus. Cette observation laisse croire que la société canadienne offre moins de mobilité qu’on le pensait. Notre analyse apporte une nouvelle perspective sur la manière dont les revenus et la compétence varient au cours d’une vie et au fil des générations, ainsi que sur le rapport entre l’inégalité et la mobilité intergénérationnelle.
Weak phase separation and the pseudogap in the electron-doped cuprates
Creators: name: Aichhorn, M.
name: Arrigoni, E.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We study the quantum transition from an antiferromagnet to a superconductor in a model for electron- and hole-doped cuprates by means of a variational cluster perturbation theory approach. In both cases, our results suggest a tendency towards phase separation between a mixed antiferromagnetic-superconducting phase at low doping and a pure superconducting phase at larger doping. However, in the electron-doped case the energy scale for phase separation is an order of magnitude smaller than for hole doping. We argue that this can explain the different pseudogap and superconducting transition scales in hole- and electron-doped materials.
description: Final version, accepted for publication in Europhysics Letters
Additive Manufacturing of Fibrous Sound Absorbers
Creators: name: Johnston, William
name: Sharma, Bhisham
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: Popular Physics (physics.pop-ph)
subject: FOS: Physical sciences

description: We investigate the possibility of additively manufacturing fibrous sound absorbers using fused deposition modeling. Two methods for 3D printing fibers are proposed. The fiber bridging method involves extruding the filament between two points with no underlying supports. The extrude-and-pull method involves extruding a filament droplet before pulling away the extruder rapidly to generate thin fibers. Both methods can produce fibers with aspect ratios greater than 100. Optical microscopy is used to investigate the effect of various printing parameters on the fiber characteristics. The sound absorption coefficient of samples printed using the two techniques are measured using a two-microphone normal incidence impedance tube setup. Effects of printing parameters and fiber density variables are experimentally studied. The experimental studies are supported by the Johnson-Champoux-Allard semi-empirical analytical model informed using an inverse characterization approach. The analytical model is then utilized to understand the effect of fiber parameters on the acoustical transport parameters. It is observed that the two methods result in individual fibers with distinct characteristics. On average, the fiber bridging method results in thicker fibers, which results in comparatively higher sound absorption. However, the extrude-and-pull method results in fibers with hair-like characteristics (thick base with progressively decreasing thickness) and one may easily incorporate it within existing additive manufacturing routines to add fibers to a base surface, thus opening up a new route towards fiber-enhanced multifunctional structures.
description: Paper accepted for publication in Additive Manufacturing
title: Dagstuhl Reports, Table of Contents, Volume 8, Issue 9, 2018
Creators: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2019
Subjects: subject: Table of Contents
subject: Frontmatter

description: Dagstuhl Reports, Table of Contents, Volume 8, Issue 9, 2018
description: Dagstuhl Reports, Volume 8, Issue 9, pages i-ii
Approach to consensus in models of continuous-opinion dynamics: a study inspired by the physics of granular gases
Creators: name: Khalil, Nagi
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: A model for continuous-opinion dynamics is proposed and studied by taking advantage of its similarities with a mono-dimensional granular gas. Agents interact as in the Deffuant model, with a parameter $α$ controlling the persuasibility of the individuals. The interaction coincides with the collision rule of two grains moving on a line, provided opinions and velocities are identified, with $α$ being the so-called coefficient of normal restitution. Starting from the master equation of the probability density of all opinions, general conditions are given for the system to reach consensus. The case when the interaction frequency is proportional to the $β$-power of the relative opinions is studied in more detail. It is shown that the mean-field approximation to the master equation leads to the Boltzmann kinetic equation for the opinion distribution. In this case, the system always approaches consensus, which can be seen as the approach to zero of the opinion temperature, a measure of the width of the opinion distribution. Moreover, the long-time behaviour of the system is characterized by a scaling solution to the Boltzmann equation in which all time dependence occurs through the temperature. The case $β=0$ is related to the Deffuant model and is analytically soluble. The scaling distribution is unimodal and independent of $α$. For $β>0$ the distribution of opinions is unimodal below a critical value of $|α|$, being multimodal with two maxima above it. This means that agents may approach consensus while being polarized. Near the critical points and for $|α|\ge 0.4$, the distribution of opinions is well approximated by the sum of two Gaussian distributions. Monte Carlo simulations are in agreement with the theoretical results.
description: 18 pages, 3 figures
title: Production Networks and the Propagation of Commodity Price Shocks
Creators: name: Dong, Wei
name: Cao, Shutao
Publisher: name: Bank of Canada
Year: 2020

description: We examine the macro implications of commodity price shocks in a model with multiple production sectors that are interconnected within a commodity-exporting small open economy. Fluctuations of commodity prices are frequently associated with the volatility of aggregate output and prices. As commodity prices rise and fall, adjustments take place in the economy, ranging from shifts in investment, employment and output to changes in interest rates and exchange rates. While these adjustments are already quite complex, one important channel often overlooked in the literature is the input-output linkages. In this paper, we examine the macro implications of commodity price shocks in a structural model with input-output linkages for a commodity-exporting small open economy. Calibrated to the Canadian economy, our model can explain a large part of the decline in real gross domestic product (GDP) that we saw in 2015 and 2016 following the sharp drop in commodity prices. We find that as the model economy adjusts to commodity price shocks, domestic downstream linkages and the export connection with the rest of the world play an important role.
description: Nous examinons les conséquences macroéconomiques de chocs de prix des produits de base dans un modèle de petite économie ouverte exportatrice de produits de base qui comporte plusieurs secteurs de production interreliés. Les variations des prix des produits de base sont souvent associées à la volatilité de la production globale et des prix. L’économie s’ajuste à mesure que les prix des produits de base montent et baissent, notamment par le redéploiement des investissements, de l’emploi et de la production, de même que par la modification des taux d’intérêt et de change. À ces ajustements déjà assez complexes s’ajoute un canal important qui est souvent négligé dans la littérature : les liens entre les entrées et les sorties. Dans cette étude, nous examinons les implications macroéconomiques des chocs de prix des produits de base dans un modèle structurel de petite économie ouverte exportatrice de produits de base où les entrées et sorties sont liées. Notre modèle calibré pour l’économie canadienne peut expliquer une bonne partie de la baisse du produit intérieur brut (PIB) réel qui a été observée en 2015 et 2016 à la suite de la forte chute des prix des produits de base. Nous constatons que les liens avec d’autres secteurs de l’économie situés en aval et les relations d’exportation avec le reste du monde jouent un rôle important lorsque l’économie modélisée s’ajuste à ces chocs.
Quantum kinetic equation and universal conductance fluctuations in graphene
Creators: name: Kechedzhi, K.
name: Kashuba, O.
name: Fal'ko, Vladimir I.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We analyze universal conductance fluctuations (UCF) in graphene in the framework of diagrammatic perturbation theory in the metallic regime. It is shown that strong inter-valley scattering lifts the valley degeneracy of electronic states, whereas at weak inter-valley scattering two valleys contribute independently such that the variance of UCF would be expected to show sample- and geometry-dependent behavior.
description: 4 pages, 1 figure; added references
Lexical elicitation: Phonological contrasts
Creators: name: Sales, Henry
name: Garvin, Karee
name: Hermalin, Noah
name: Melguy, Yevgeniy
name: Michael, Lev
name: Scott, Tessa
name: Wilbanks, Eric
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2021
Subjects: subject: mam

description: Includes velar, alveolar, and vocalic contrasts. Lead elicitor: Noah Hermalin. Scribe: Eric Wilbanks. Clean copy: Karee Garvin.
title: Dagstuhl Reports, Table of Contents, Volume 8, Issue 10, 2018
Creators: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2019
Subjects: subject: Table of Contents
subject: Frontmatter

description: Dagstuhl Reports, Table of Contents, Volume 8, Issue 10, 2018
description: Dagstuhl Reports, Volume 8, Issue 10, pages i-ii
Butterfly Effect and Spatial Structure of Information Spreading in a Chaotic Cellular Automaton
Creators: name: Liu, Shuwei
name: Willsher, J.
name: Bilitewski, T.
name: Li, Jinjie
name: Smith, A.
name: Christensen, K.
name: Moessner, R.
name: Knolle, J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Inspired by recent developments in the study of chaos in many-body systems, we construct a measure of local information spreading for a stochastic Cellular Automaton in the form of a spatiotemporally resolved Hamming distance. This decorrelator is a classical version of an Out-of-Time-Order Correlator studied in the context of quantum many-body systems. Focusing on the one-dimensional Kauffman Cellular Automaton, we extract the scaling form of our decorrelator with an associated butterfly velocity $v_b$ and a velocity-dependent Lyapunov exponent $λ(v)$. The existence of the latter is not a given in a discrete classical system. Second, we account for the behaviour of the decorrelator in a framework based solely on the boundary of the information spreading, including an effective boundary random walk model yielding the full functional form of the decorrelator. In particular, we obtain analytic results for $v_b$ and the exponent $β$ in the scaling ansatz $λ(v) \sim μ(v - v_b)^β$, which is usually only obtained numerically. Finally, a full scaling collapse establishes the decorrelator as a unifying diagnostic of information spreading.
description: 5+1 pages, 4 figures
Size quantization of an exciton: A toy model of the "dead layer"
Creators: name: Raikh, M. E.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Size-quantization levels of an exciton in large nanocrystals is studied theoretically. For the nanocrystal size, $L$, much bigger than the Bohr radius, $a_B$, the level positions do not depend on $a_B$. The correction to the levels in a small parameter $a_B/L$ depends on the reflection phase of the exciton from the boundary. Calculation of this phase constitutes a three-body problem: electron, hole, and the boundary. This calculation can be performed analytically in the limit when the hole is much heavier than the electron. Physically, a slow motion of the hole towards the boundary takes place in the effective potential created by the fast motion of the electron orbiting the hole and touching the boundary. As a result, the hole is reflected before reaching the boundary. The distance of the closest approach of the hole to the boundary (the dead layer) exceeds $a_B$ parametrically.
description: 6 pages, 1 figure
Non-Markovianity, entropy production, and Jarzynski equality
Creators: name: Martins, J.
name: Defaveri, L.
name: Soares-Pinto, D. O.
name: Queirós, S. M. D.
name: Morgado, W. A. M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We explore the role a non-Markovian memory kernel plays on information exchange and entropy production in the context of a external work protocol. The Jarzynski Equality is shown to hold for both the harmonic and the non-harmonic models. We observe the memory function acts as an information pump, recovering part of the information lost to the thermal reservoir as a consequence of the non-equilibrium work protocol. The pumping action occurs for both the harmonic and non-harmonic cases. Unexpectedly, we found that the harmonic model does not produce entropy, regardless of the work protocol. The presence of even a small amount of non-linearity recovers the more normal entropy producing behaviour, for out-of-equilibrium protocols.
description: 32 pages, 18 figures
Deceleration without dark matter
Creators: name: Jackson, J C
name: Dodgson, Marina
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In homogeneous isotropic cosmological models the angular size theta of a standard measuring rod changes with redshift z in a manner that depends upon the parameters of the model. It has been argued that as a population ultracompact (milliarcsecond) radio sources measured by very long-baseline interferometry (VLBI) do not evolve with cosmic epoch, and thus comprise a set of standard objects, at least in a statistical sense. Here we examine the angular-size/redshift relation for 256 ultracompact sources with z in the range 0.5 to 3.8 for cosmological models with two degrees of freedom (Omega_0 and Lambda_0). The canonical inflationary cold dark matter model(Omega_0=1, Lambda_0=0) appears to be ruled out by the observed relationship, whereas low-density models with a cosmological constant of either sign are favoured.
description: Although published (MNRAS 285, 806, 1997, submitted 1996 May 3), this paper has not previously appeared on the arXive. Despite its title, a prominent conclusion is that if the Universe is spatially flat, then the best cosmological parameters are Omega_m=0.2, Omega_Lambda=0.8, with probable range 0.1
Kaluza-Klein gravitons at the LHC and in extensive air showers
Creators: name: Kisselev, A. V.
name: Petrov, V. A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The small curvature option of the Randall-Sundrum model with two branes is considered which has almost continuous spectrum of low-mass Kaluza-Klein gravitons. It is shown that gravity effects related with these excitations can be detected in double diffractive events at the LHC and in inclined air showers induced by interactions of cosmic neutrinos with atmospheric nucleons at ultra-high energies.
description: 8 pages, 4 figures, talk given at the International Conference on Interconnection between High Energy Physics and Astroparticle Physics: From Colliders to Cosmic Rays, 7-13 September 2005, Prague, Czech Republic
Properties of a Previously Unidentified Instrumental Signature in $\textit{Kepler/K2}$ that was Confused for AGN Variability
Creators: name: Moreno, Jackeline
name: Buttry, Rachel
name: O'Brien, John
name: Vogeley, Michael S.
name: Richards, Gordon T.
name: Smith, Krista Lynne
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The $\textit{Kepler}$ satellite potentially provides the highest precision photometry of active galactic nuclei (AGN) available to investigate short-timescale optical variability. We targeted quasars from the Sloan Digital Sky Survey that lie in the fields of view of the $\textit{Kepler/K2}$ campaigns. Based on those observations, we report the discovery and properties of a previously unidentified instrumental signature in K2. Systematic errors in K2, beyond those due to the motion of the detector, plague our AGN and other faint-target, guest-observer science proposals. Weakly illuminated pixels are dominated by low frequency trends that are both non-astrophysical and correlated from object to object. A critical clue to understanding this instrumental noise is that different targets observed in the same channels of Campaign 8 (rear facing) and Campaign 16 (forward facing) had nearly identical light curves after time reversal of one of the campaigns. This observation strongly suggests that the underlying problem relates to the relative Sun-spacecraft-field orientation, which was approximately the same on day 1 of Campaign 8 as the last day of Campaign 16. Furthermore, we measure that the instrumental signature lags in time as a function of radius from the center of the detector, crossing channel boundaries. Systematics documented in this investigation are unlikely to be due to Moiré noise, rolling band, or pointing jitter. Instead this work strongly suggests temperature-dependent focus changes that are further subject to channel variations. Further characterization of this signature is crucial for rehabilitating K2 data for use in investigations of AGN light curves.
description: 21 pages, 16 figures
Path-integral calculation of the fourth virial coefficient of helium isotopes
Creators: name: Garberoglio, Giovanni
name: Harvey, Allan H.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We use the path-integral Monte Carlo (PIMC) method and state-of-the-art two-body and three-body potentials to calculate the fourth virial coefficients $D(T)$ of $^4$He and $^3$He as functions of temperature from 2.6K to 2000K. We derive expressions for the contributions of exchange effects due to the bosonic or fermionic nature of the helium isotope; these effects have been omitted from previous calculations. The exchange effects are relatively insignificant for $^4$He at the temperatures considered, but for $^3$He they are necessary for quantitative accuracy below about 4K. Our results are consistent with previous theoretical work (and with some of the limited and scattered experimental data) for $^4$He; for $^3$He there are no experimental values and this work provides the first values of $D(T)$ calculated at this level. The uncertainty of the results depends on the statistical uncertainty of the PIMC calculation, the estimated effect of omitting four-body and higher terms in the potential energy, and the uncertainty contribution propagated from the uncertainty of the potentials. At low temperatures, the uncertainty is dominated by the statistical uncertainty of the PIMC calculations, while at high temperatures the uncertainties related to the three-body potential and to omitted higher-order contributions become dominant.
description: 13 pages, 3 figures. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Chem. Phys. 154, 104107 (2021) and may be found at https://doi.org/10.1063/5.0043446
Analogy between Three-Dimensional Helimagnetic Metals and Two-Dimensional Nonmagnetic Metals: Transport in the Weak-Disorder Regime
Creators: name: Kirkpatrick, T. R.
name: Belitz, D.
name: Saha, Ronojoy
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We present a quasi-particle model that allows for a simple description of the electronic properties of metallic helimagnets. For weak quenched disorder, we find a leading linear temperature dependence of the electrical conductivity for 3-d materials. This is reminiscent of the behavior of nonmagnetic 2-d systems, and reflects a general tendency of certain properties of bulk helimagnets to appear effectively 2-d. The sign of the effect is opposite to that in nonmagnetic 2-d materials. These surprising predictions should be observable in weak helimagnets.
description: 4pp, 2 figs, final version to be published
title: Dagstuhl Reports, Table of Contents, Volume 8, Issue 11, 2018
Creators: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2019
Subjects: subject: Table of Contents
subject: Frontmatter

description: Dagstuhl Reports, Table of Contents, Volume 8, Issue 11, 2018
description: Dagstuhl Reports, Volume 8, Issue 11, pages i-ii
title: A Bitcoin Standard: Lessons from the Gold Standard
Creators: name: Weber, Warren E.
Publisher: name: Bank of Canada
Year: 2016

description: This paper imagines a world in which countries are on the Bitcoin standard, a monetary system in which all media of exchange are Bitcoin or are backed by it. The paper explores the similarities and differences between the Bitcoin standard and the gold standard and describes the media of exchange that would exist under the Bitcoin standard. Because the Bitcoin standard would closely resemble the gold standard, the paper explores the lessons about how it would perform by examining the classical gold standard period, specifically 1880–1913. The paper argues that because there would be virtually no arbitrage costs for international transactions, countries could not follow independent interest rate policies under the Bitcoin standard. However, central banks would still have some limited ability to act as lenders of last resort. Based on the experience during the classical gold standard period, the paper conjectures that there would be mild deflation and constant exchange rates under the Bitcoin standard. The paper also conjectures how long the Bitcoin standard might last if it were to come into existence.
description: Dans ce document, nous imaginons un monde où le bitcoin est la monnaie étalon des pays, soit un système monétaire au sein duquel tous les échanges se font au moyen du bitcoin ou sont garantis par celui-ci. Nous décrivons la manière dont se feraient les échanges sous le régime d’étalon-bitcoin, et explorons les similitudes et les différences avec l’étalon-or. Étant donné que les deux régimes se ressembleraient beaucoup, nous tentons de déterminer les leçons que l’on pourrait tirer de l’utilisation du bitcoin comme étalon en examinant la période de l’étalon-or classique (de 1880 à 1913). Nous soutenons que, puisque les coûts liés à l’arbitrage seraient pratiquement nuls pour les opérations internationales, les pays ne pourraient pas suivre de politique indépendante en matière de taux d’intérêt sous l’étalon-bitcoin. Cependant, les banques centrales conserveraient une capacité limitée de jouer le rôle de prêteur de dernier ressort. En nous basant sur l’expérience vécue pendant la période de l’étalon-or classique, nous supposons que l’adoption du bitcoin comme étalon entraînerait une légère déflation et une stabilisation des taux de change. Nous estimons également la durée probable d’un tel régime.
Second derivatives estimate of suitable solutions to the 3D Navier-Stokes equations
Creators: name: Vasseur, Alexis
name: Yang, Jincheng
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 76D05, 35Q30

description: We study the second spatial derivatives of suitable weak solutions to the incompressible Navier-Stokes equations in dimension three. We show that it is locally $L ^{\frac43, q}$ for any $q > \frac43$, which improves from the current result $L ^{\frac43, \infty}$. Similar improvements in Lorentz space are also obtained for higher derivatives of the vorticity for smooth solutions. We use a blow-up technique to obtain nonlinear bounds compatible with the scaling. The local study works on the vorticity equation and uses De Giorgi iteration. In this local study, we can obtain any regularity of the vorticity without any a priori knowledge of the pressure. The local-to-global step uses a recently constructed maximal function for transport equations.
description: 39 pages
J/Psi strong couplings to the vector mesons
Creators: name: Laporta, V.
name: Piccinini, F.
name: Polosa, A. D.
name: Riquer, V.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present a study of the cross sections J/Psi X --> D^(*) \bar D^(*) (X = rho, Phi) based on the calculation of the effective tri- and four-linear couplings J/Psi (X) D^(*) \bar D^(*) within a constituent quark model. In particular, the details of the calculation of the four-linear couplings J/Psi X D^(*)\bar D^(*) are given. The results obtained have been used in a recent analysis of J/Psi absorption by the hot hadron gas formed in peripheral heavy-ion collisions at SPS energies.
description: 12 pages, 3 figures
Radiation transport equations in non-Riemannian space-times
Creators: name: Cheng, K. S.
name: Harko, T.
name: Wang, X. Y.
Publisher: name: arXiv
Year: 2005
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The transport equations for polarized radiation transfer in non-Riemannian, Weyl-Cartan type space-times are derived, with the effects of both torsion and non-metricity included. To obtain the basic propagation equations we use the tangent bundle approach. The equations describing the time evolution of the Stokes parameters, of the photon distribution function and of the total polarization degree can be formulated as a system of coupled first order partial differential equations. As an application of our results we consider the propagation of the cosmological gamma ray bursts in spatially homogeneous and isotropic spaces with torsion and non-metricity. For this case the exact general solution of the equation for the polarization degree is obtained, with the effects of the torsion and non-metricity included. The presence of a non-Riemannian geometrical background in which the electromagnetic fields couple to torsion and/or non-metricity affect the polarization of photon beams. Consequently, we suggest that the observed polarization of prompt cosmological gamma ray bursts and of their optical afterglows may have a propagation effect component, due to a torsion/non-metricity induced birefringence of the vacuum. A cosmological redshift and frequency dependence of the polarization degree of gamma ray bursts also follows from the model, thus providing a clear observational signature of the torsional/non-metric effects. On the other hand, observations of the polarization of the gamma ray bursts can impose strong constraints on the torsion and non-metricity and discriminate between different theoretical models.
description: 12 pages, 3 figures, accepted for publication in PRD
Unequal-mass mergers of dark matter haloes with rare and frequent self-interactions
Creators: name: Fischer, Moritz S.
name: Brüggen, Marcus
name: Schmidt-Hoberg, Kai
name: Dolag, Klaus
name: Ragagnin, Antonio
name: Robertson, Andrew
Publisher: name: Deutsches Elektronen-Synchrotron, DESY, Hamburg
Year: 2021
Subjects: subject: 520
subject: dark matter: halo
subject: gravitation: potential
subject: dark matter: scattering
subject: galaxy: cluster
subject: star
subject: wide-angle
subject: small-angle
subject: coalescence
subject: many-body problem
subject: mass ratio
subject: phase space
subject: cosmological model
subject: self-force
subject: numerical calculations

description: Oxford Univ. Press (2021).
description: Dark matter self-interactions have been proposed to solve problems on small length scales within the standard cold dark matter cosmology. Here we investigate the effects of dark matter self-interactions in merging systems of galaxies and galaxy clusters with equal and unequal mass ratios. We perform N-body dark matter-only simulations of idealised setups to study the effects of dark matter self-interactions that are elastic and velocity-independent. We go beyond the commonly adopted assumption of large-angle (rare) dark matter scatterings, paying attention to the impact of small-angle (frequent) scatterings on astrophysical observables and related quantities. Specifically, we focus on dark matter-galaxy offsets, galaxy-galaxy distances, halo shapes, morphology and the phase-space distribution. Moreover, we compare two methods to identify peaks: one based on the gravitational potential and one based on isodensity contours. We find that the results are sensitive to the peak finding method, which poses a challenge for the analysis of merging systems in simulations and observations, especially for minor mergers. Large dark matter-galaxy offsets can occur in minor mergers, especially with frequent self-interactions. The subhalo tends to dissolve quickly for these cases. While clusters in late merger phases lead to potentially large differences between rare and frequent scatterings, we believe that these differences are non-trivial to extract from observations. We therefore study the galaxy/star populations which remain distinct even after the dark matter haloes have coalesced. We find that these collisionless tracers behave differently for rare and frequent scatterings, potentially giving a handle to learn about the micro-physics of dark matter.
description: Published by Oxford Univ. Press
Effect of geometric parameters on the noise generated by rod-airfoil configuration
Creators: name: Sharma, Sparsh
name: Geyer, Thomas F.
name: Giesler, Jens
Publisher: name: arXiv
Year: 2020
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: This paper investigates the effect of the geometric parameters -- rod diameter and the distance between the rod and the airfoil -- on the noise generated by rod-airfoil configuration using experimental and numerical techniques. The numerical simulations are carried out using the low-dissipation up-wind scheme and the Delayed-Detached-Eddy Simulation (DDES) approach with Shear-Layer Adapted (SLA) sub-grid length scale (SGS) for a faster transition between RANS and LES. A dual-time stepping strategy, leading to second-order accuracy in space and time, is followed. The Ffowcs-Williams and Hawkings (FWH) technique is used to post-process the pressure fluctuations to predict the far~field acoustics. A corresponding detailed experimental analysis, carried out using phased microphone array techniques in the aeroacoustic wind tunnel at the Brandenburg Technical University at Cottbus, is used for the validation of the numerical method. The key objective of the analysis is to examine the influence of the parameters of the configuration on the noise generation. The results show reasonable agreement with the experimental data in terms of far-field acoustics.
description: 14 pages, 12 figures, it is a draft manuscript
Analytical solution of the Thomas-Fermi equation for atoms
Creators: name: Oulne, M.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: An approximate analytical solution of the Thomas-Fermi equation for neutral atoms is obtained, using the Ritz variational method, which reproduces accurately the numerical solution, in the range $0\leq x\leq50$, and its derivative at $x=0$. The proposed solution is used to calculate the total ionization energies of heavy atoms. The obtained results are in good agreement with the Hartree-Fock ones and better than those obtained from previously proposed trial functions by other authors.
description: Revtex, 4 pages, 2 figures
Novikov structures on solvable Lie algebras
Creators: name: Burde, Dietrich
name: Dekimpe, Karel
Publisher: name: arXiv
Year: 2005
Subjects: subject: Mathematical Physics (math-ph)
subject: Rings and Algebras (math.RA)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 17B30;17D25;17B69

description: We study Novikov algebras and Novikov structures on finite-dimensional Lie algebras. We show that a Lie algebra admitting a Novikov structure must be solvable. Conversely we present an example of a nilpotent 2-step solvable Lie algebra without any Novikov structure. We construct Novikov structures on certain Lie algebras via classical r-matrices and via extensions. In the latter case we lift Novikov structures on an abelian Lie algebra A and a Lie algebra B to certain extensions of B by A. We apply this to prove the existence of affine and Novikov structures on several classes of 2-step solvable Lie algebras. In particular we generalize a well known result of Scheuneman concerning affine structures on 3-step nilpotent Lie algebras.