cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
alpha_s and the tau hadronic width: fixed-order, contour-improved and higher-order perturbation theory
Creators: name: Beneke, Martin
name: Jamin, Matthias
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The determination of $α_s$ from hadronic $τ$ decays is revisited, with a special emphasis on the question of higher-order perturbative corrections and different possibilities of resumming the perturbative series with the renormalisation group: fixed-order (FOPT) vs. contour-improved perturbation theory (CIPT). The difference between these approaches has evolved into a systematic effect that does not go away as higher orders in the perturbative expansion are added. We attempt to clarify under which circumstances one or the other approach provides a better approximation to the true result. To this end, we propose to describe the Adler function series by a model that includes the exactly known coefficients and theoretical constraints on the large-order behaviour originating from the operator product expansion and the renormalisation group. Within this framework we find that while CIPT is unable to account for the fully resummed series, FOPT smoothly approaches the Borel sum, before the expected divergent behaviour sets in at even higher orders. Employing FOPT up to the fifth order to determine $α_s$ in the $\MSb$ scheme, we obtain $α_s(M_τ)=0.320 {}^{+0.012}_{-0.007}$, corresponding to $α_s(M_Z) = 0.1185 {}^{+0.0014}_{-0.0009}$. Improving this result by including yet higher orders from our model yields $α_s(M_τ)=0.316 \pm 0.006$, which after evolution leads to $α_s(M_Z) = 0.1180 \pm 0.0008$. Our results are lower than previous values obtained from $τ$ decays.
description: 42 pages, 9 figures; appendix on Adler function in the complex plane added. Version to appear in JHEP
Origin of ultra-high energy cosmic rays in the era of Auger and Telescope Array
Creators: name: Inoue, Susumu
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The origin of ultra-high energy cosmic rays is discussed in light of the latest observational results from the Pierre Auger Observatory, highlighting potential astrophysical sources such as active galactic nuclei, gamma-ray bursts, and clusters of galaxies. Key issues include their energy budget, the acceleration and escape of protons and nuclei, and their propagation in extragalactic radiation and magnetic fields. We briefly address the prospects for Telescope Array and future facilities such as JEM-EUSO, and also emphasize the importance of multi-messenger X-ray and gamma-ray signatures in addition to neutrinos as diagnostic tools for source identification.
description: Proceedings of 10th Int. Conf. on TAUP 2007, invited plenary talk; published in J. Phys. Conf. Ser
Discerning Incompressible and Compressible Phases of Cold Atoms in Optical Lattices
Creators: name: Scarola, V. W.
name: Pollet, L.
name: Oitmaa, J.
name: Troyer, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Experiments with cold atoms trapped in optical lattices offer the potential to realize a variety of novel phases but suffer from severe spatial inhomogeneity that can obscure signatures of new phases of matter and phase boundaries. We use a high temperature series expansion to show that compressibility in the core of a trapped Fermi-Hubbard system is related to measurements of changes in double occupancy. This core compressibility filters out edge effects, offering a direct probe of compressibility independent of inhomogeneity. A comparison with experiments is made.
title: The potential for Environmental Impact Assessment (EIA) in Iran’s Water Management
Creators: name: Khosravi, Fatemeh
Publisher: name: University of Liverpool Repository
Year: 2019

description: There is a growing international body of literature on Environmental Impact Assessment (EIA) effectiveness, but to date little EIA-related research has been undertaken in Iran despite of its inception in 1994. This research, therefore, aims to evaluate Iran’s EIA system, examine its effectiveness and provide recommendations to enhance it. In doing so the first section of this research undertakes an evaluation of the Iranian EIA system, focusing on EIA legislation, administration and processes. This research then examines EIA effectiveness in Iran by looking at water management in the Urmia Lake Basin (ULB). ULB was used as a case study area to investigate the extent to which EIA is delivering environmental protection within the water sector in Iran. In doing so, an EIA effectiveness framework is developed and applied for assessing the extent to which EIA has been effective in the ULB. The research helps in establishing that in Iran, environmental consideration is absent above the project level but even for EIA, the activities are rather restricted. EIA is not able to address and mitigate the negative effects of extensive water exploitation through dam building. Based on the findings, some recommendations are provided in the last section of this research. These were further developed in consideration of EIA reviews undertaken in other countries and opinions of Iranian EIA experts were also incorporated which were collected through semi-structured interviews. This research contributes to academic literature in three important ways: First, it provides a thorough review of the Iranian EIA system. Second, it confirms that EIA is not procedurally and substantively effective by examining EIA effectiveness in Iranian water management sector. It also reveals how contextual factors can constraint EIA effectiveness in Iran. Finally, it provides recommendations to improve Iran’s EIA system by evaluating the feasibility of adopting these ‘recommendations’ within Iran, taking into consideration the contextual factors of the country.
Quantum field thermalization in expanding backgrounds
Creators: name: Tranberg, Anders
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The 2PI effective action formalism for quantum fields out of equilibrium is set up in an expanding (Friedmann-Robertson-Walker) background. We write down and solve the evolution equations for a phi^4 model at NLO in a coupling expansion. We comment on issues of renormalization, lattice discretization and the range of applicability of the approach. A number of example calculations are presented, including thermalization and (p)reheating. Generalizations to more complicated systems and applications are discussed.
description: 27 pages, 11 figures. Some modifications and clarifications in presentation. Minor errors and some typos fixed. Conclusions unchanged. Published version
Interference fringes in a nonlinear Michelson interferometer based on spontaneous parametric down-conversion
Creators: name: Yang, Chen
name: Zhou, Zhi-Yuan
name: Wang, Liu-Long
name: Li, Yan
name: Liu, Shi-Kai
name: Ge, Zheng
name: Zhang, Xiao-Chun
name: Tang, Qing
name: Guo, Guang-Can
name: Shi, Bao-Sen
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Quantum nonlinear interferometers (QNIs) can measure the infrared physical quantities of a sample by detecting visible photons. A QNI with Michelson geometry based on the spontaneous parametric down-conversion in a second-order nonlinear crystal is studied systematically. A simplified theoretical model of the QNI is presented. The interference visibility, coherence length, equal-inclination interference, and equal-thickness interference for the QNI are demonstrated theoretically and experimentally. As an application example of the QNI, the refractive index and the angle between two surfaces of a BBO crystal are measured using equal-inclination interference and equal-thickness interference.
description: 20 pages, 9 figures
Towards M2-brane Theories for Generic Toric Singularities
Creators: name: Franco, Sebastian
name: Hanany, Amihay
name: Park, Jaemo
name: Rodriguez-Gomez, Diego
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We construct several examples of (2+1) dimensional N=2 supersymmetric Chern-Simons theories, whose moduli space is given by non-compact toric Calabi-Yau four-folds, which are not derivable from any (3+1) dimensional CFT. One such example is the gauge theory associated with the cone over Q^{111}. For several examples, we explicitly confirm the matter content, superpotential interactions and RG flows suggested by crystal models. Our results provide additional support to the idea that crystal models are relevant for describing the structure of these CFTs.
description: 33 pages, 16 figures
Structural properties, defects and structural phase transition in the ROFeM (R=La, Nd; M=As, P) materials
Creators: name: Ma, C.
name: Zeng, L. J.
name: Yang, H. X.
name: Shi, H. L
name: Che, R. C.
name: Liang, C. Y.
name: Qin, Y. B.
name: Chen, G. F.
name: Ren, Z. A.
name: Li, J. Q.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The structural properties of the ROFeM (R=La, Nd; M=As, P) materials have been analyzed by means of electron diffraction, high-resolution transmission-electron microscopy (TEM) and in-situ cooling TEM observations. The experimental results demonstrate that the layered ROFeM crystals often contain a variety of structural defects, such as stacking faults and small-angle boundaries. The in-situ TEM investigations reveal that, in association with the remarkable spin-density-wave (SDW) instability near 150 K, complex structural transitions can be clearly observed in both crystal symmetry and local microstructure features.
description: 17 pages, 6 figures
title: Front Matter, Table of Contents, Preface, Conference Organization
Creators: name: Kimelfeld, Benny
name: Amsterdamer, Yael
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2018
Subjects: subject: Front Matter
subject: Table of Contents
subject: Preface
subject: Conference Organization

description: Front Matter, Table of Contents, Preface, Conference Organization
description: LIPIcs, Vol. 98, 21st International Conference on Database Theory (ICDT 2018), pages 0:i-0:xvi
Axion-like dark matter clouds around rotating black holes
Creators: name: KIczek, Bartlomiej
name: Rogatko, Marek
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Numerical analysis of dark matter axion-like cloud in the vicinity of rotating black hole has been performed. The model where axion-like scalar field is non-trivially coupled to Maxwell field is studied in the spacetime of Kerr black hole in uniform magnetic field and in Kerr-Newman one. The dependence of scalar mass and black hole angular momentum on accumulation of axion dark matter cloud was given. It was revealed that condensation of the dark matter clouds is preferable for a very small mass of axion.
description: 18 pages, RevTex, 9 figures, to be published in Phys. Rev. D15
Evaluation of Modern 3He(alpha,gamma)7Be Data
Creators: name: Cyburt, Richard H.
name: Davids, Barry
Publisher: name: arXiv
Year: 2008
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: Astrophysics (astro-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: In both the Sun and the early universe, the 3He(alpha,gamma)7Be reaction plays a key role. The rate of this reaction is the least certain nuclear input needed to calculate both the primordial 7Li abundance in big bang nucleosynthesis (BBN) and the solar neutrino flux. Taking advantage of several recent highly precise experiments, we analyse modern 3He(alpha,gamma)7Be data using a robust and minimally model dependent approach capable of handling discrepant data sets dominated by systematic rather than statistical errors. We find S34(0)=0.580 pm 0.043(0.054) keV b at the 68.3(95.4)% confidence level.
description: 13 pages, 5 figures
Scalable transparent conductive thin films with electronically passive interfaces for direct chemical vapor deposition of 2D materials
Creators: name: Grünleitner, Theresa
name: Henning, Alex
name: Bissolo, Michele
name: Kleibert, Armin
name: Vaz, Carlos A. F.
name: Stier, Andreas V.
name: Finley, Jonathan J.
name: Sharp, Ian D.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present a novel transparent conductive support structure for two-dimensional (2D) materials that provides an electronically passive 2D/3D interface while also enabling facile interfacial charge transport. This structure, which comprises an evaporated nanocrystalline carbon (nc-C) film beneath an atomic layer deposited alumina (ALD AlOx) layer, is thermally stable and allows direct chemical vapor deposition (CVD) of 2D materials onto the surface. When the nc-C/AlOx is deposited onto a 270 nm SiO2 layer on Si, strong optical contrast for monolayer flakes is retained. Raman spectroscopy reveals good crystal quality for MoS2 and we observe a ten-fold photoluminescence intensity enhancement compared to flakes on conventional Si/SiO2. Tunneling across the ultrathin AlOx enables interfacial charge injection, which we demonstrate by artifact-free scanning electron microscopy and photoemission electron microscopy. Thus, this combination of scalable fabrication and electronic conductivity across a weakly interacting 2D/3D interface opens up new application and characterization opportunities for 2D materials.
description: 28 pages, 9 figures
A Declarative Language for Preserving Consistency of Multiple Models
Creators: name: Gleitze, Joshua
Publisher: name: Karlsruher Institut für Technologie (KIT)
Year: 2017

description: Der Einsatz mehrerer Modelle zur Beschreibung eines Softwaresystems birgt oftmals die Herausforderung, diese konsistent zu halten. Während es viel Forschung zur Konsistenzhaltung zweier Modelle gibt, untersuchen nur wenige Arbeiten die Spezifika der Konsistenzhaltung mehrerer Modelle. In dieser Bachelorarbeit wird eine neue Programmiersprache vorgestellt, die es erlaubt, Transformationen zu erstellen, die mehr als zwei Modelle konsistent halten. Die Sprache verwendet ein Zwischen-Metamodell, sodass alle Transformationen zuerst von einem existierenden Modell in das Zwischenmodell und dann erst in die anderen Modelle ausgeführt werden. Zunächst betrachten wir verschiedene Möglichkeiten, wie Modelle mit ausschließlich binären Transformationen konsistent gehalten werden können. Im Weiteren demonstrieren wir Vorteile davon, ein Zwischen-Metamodell in den Konsistenzhaltungsprozess einzuführen. Im nächsten Schritt präsentieren wir die Gemeinsamkeiten-Sprache als eine Möglichkeit der Konsistenzhaltung mittels Zwischen-Metamodellen. Sie ermöglicht Entwicklern, Metaklassen des Zwischen-Metamodells gemeinsam mit deren Attributen und Referenzen zu deklarieren. Die Abbildungen vom Zwischenmodell in die Modelle, die konsistent gehalten werden sollen, und zurück, können direkt in den Zwischen-Metaklassen, -Attributen und -Referenzen festgelegt werden. Um Logik nicht zu duplizieren, können bidirektionale Ausdrücke für die Abbildungen verwendet werden. Die Sprache ist deklarativ und soll auf diese Weise eine hohe Nachvollziehbarkeit der Transformationen ermöglichen. Wir haben ein prototypische Implementierung der Sprache für Vitruvius erstellt, die in Eclipse für EMF-Modelle verwendet werden kann. Die Implementierung kann als Machbarkeitsnachweis gesehen werden, eignet sich allerdings noch nicht für den Praxiseinsatz. Die Idee, Zwischen-Metamodelle für die skalierbare und modulare Konsistenzhaltung mehrerer Modelle einzusetzen, wurde in anderen Arbeiten in realistische Szenarien bereits erfolgreich umgesetzt. Soweit uns bekannt ist, existiert noch kein Ansatz, der es erlaubt, ein Zwischen-Metamodell und die Transformationen für dieses in der selben Sprache zu definieren.
Mon Buddhist Architecture in Pakkret District, Nonthaburi Province, Thailand during Thonburi and Rattanakosin Periods (1767-1932)
Creators: name: Jirada Praebaisri
name: Koompong Noobanjong
Publisher: name: Silpakorn University Research, Innovation and Creativity Administration Office
Year: 2019
Subjects: Buddhist architecture
Mon
Thonburi to Rattanakosin periods
Pakkret

description: Humanities, Arts and Social Sciences Studies, 19, 1, 30-58
Psychosocial Review of Drug Substance Use among Transgender In Penang, Malaysia
Creators: name: Kumarashwaran Vadevelu
name: Effendi, Sulaiman
name: Singh, Paramjit Singh Jamir
name: Radin Firdaus Radin Badaruddin
name: Samsurijan, Mohamad Shaharudin
name: Latif, Abdul Rais Abdul
name: Mohd Haizzan Yahaya
Publisher: name: Silpakorn University Research, Innovation and Creativity Administration Office
Year: 2019
Subjects: Transgender
drug substance use
psychosocial review

description: Humanities, Arts and Social Sciences Studies, 19, 1, 59-69
A Note on Occur-Check
Creators: name: Drabent, Włodzimierz
Publisher: name: arXiv
Year: 2021
Subjects: subject: Logic in Computer Science (cs.LO)
subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences
subject: D.1.6; F.3.3; F.3.1

description: Most known results on avoiding the occur-check are based on the notion of "not subject to occur-check" (NSTO). It means that unification is performed only on such pairs of atoms for which the occur-check never succeeds in any run of a nondeterministic unification algorithm. Here we show that this requirement is too strong. We show how to weaken it, and present some related sufficient conditions under which the occur-check may be safely omitted. We show examples for which the proposed approach provides more general results than the approaches based on well-moded and nicely moded programs (this includes cases to which the latter approaches are inapplicable).
description: In Proceedings ICLP 2021, arXiv:2109.07914
Exposition to Staggered Multi-Field Inflation
Creators: name: Battefeld, Thorsten
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: I investigate multi-field inflationary models with fields that decay during inflation, leading to staggered inflation. This feature is natural in many models motivated by string theory, for instance if inflatons are related to interbrane distances and the branes start to annihilate during inflation. A short exposition to an analytic framework is provided, enabling the computation of leading order corrections to observables, i.e. the scalar spectral index.
description: 4 pages, proceedings for work presented at COSMO08 and Cargese08
Competition between antiferromagnetism and superconductivity, electron-hole doping asymmetry and "Fermi Surface" topology in cuprates
Creators: name: Pathak, Sandeep
name: Shenoy, Vijay B.
name: Randeria, Mohit
name: Trivedi, Nandini
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We investigate the asymmetry between electron and hole doping in a 2D Mott insulator, and the resulting competition between antiferromagnetism (AF) and d-wave superconductivity (SC), using variational Monte Carlo for projected wave functions. We find that key features of the T = 0 phase diagram, such as critical doping for SC-AF coexistence and the maximum value of the SC order parameter, are determined by a single parameter which characterises the topology of the "Fermi surface" at half filling defined by the bare tight-binding parameters. Our results give insight into why AF wins for electron doping, while SC is dominant on the hole doped side. We also suggest using band structure engineering to control the parameter for enhancing SC.
description: 4 pages, 4 figures
Flux dependent 1.5 MeV self-ion beam induced sputtering from Gold nanostructured thin films
Creators: name: Ghatak, J.
name: Sundaravel, B.
name: Nair, K. G. M.
name: Satyam, P. V.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We discuss four important aspects of 1.5 MeV Au2+ ion-induced flux dependent sputtering from gold nanostrcutures (of an average size 7.6 nm and height 6.9 nm) that are deposited on silicon substrates: (a) Au sputtering yield at the ion flux of 6.3x10^12 ions cm-2 s-1 is found to be 312 atoms/ion which is about five times the sputtering yield reported earlier under identical irradiation conditions at a lower beam flux of 10^9 ions cm-2 s-1, (b) the sputtered yield increases with increasing flux at lower fluence and reduces at higher fluence (1.0x10^15 ions cm-2) for nanostructured thin films while the sputtering yield increases with increasing flux and fluence for thick films (27.5 nm Au deposited on Si) (c) Size distribution of sputtered particles has been found to vary with the incident beam flux showing a bimodal distribution at higher flux and (d) the decay exponent obtained from the size distributions of sputtered particles showed an inverse power law dependence ranging from 1.5 to 2.5 as a function of incident beam flux. The exponent values have been compared with existing theoretical models to understand the underlying mechanism. The role of wafer temperature associated with the beam flux has been invoked for a qualitative understanding of the sputtering results in both the nanostructured thin films and thick films.
description: 25 pages, 5 figures, 1 table To be Appeared in J. Phys. D: Appl. Phys
The Cosmic Crystallinity Conundrum: Clues from IRAS 17495-2534
Creators: name: Speck, Angela K.
name: Whittington, Alan G.
name: Tartar, Josh B.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Since their discovery, cosmic crystalline silicates have presented several challenges to understanding dust formation and evolution. The mid-infrared spectrum of IRAS 17495$-$2534, a highly obscured oxygen-rich asymptotic giant branch (AGB) star, is the only source observed to date which exhibits a clear crystalline silicate absorption feature. This provides an unprecedented opportunity to test competing hypotheses for dust formation. Observed spectral features suggest that both amorphous and crystalline dust is dominated by forsterite (Mg\_2 SiO\_4) rather than enstatite (MgSiO\_3) or other silicate compositions. We confirm that high mass-loss rates should produce more crystalline material, and show why this should be dominated by forsterite. The presence of Mg\_2 SiO\_4 glass suggests that another factor (possibly C/O) is critical in determining astromineralogy. Correlation between crystallinity, mass-loss rate and initial stellar mass suggests that only the most massive AGB stars contribute significant quantities of crystalline material to the interstellar medium, resolving the conundrum of its low crystallinity.
description: 12 pages, 2 figures
Composite Entanglement Topology and Extensional Rheology of Symmetric Ring-Linear Polymer Blends
Creators: name: O'Connor, Thomas C.
name: Ge, Ting
name: Grest, Gary S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Extensive molecular simulations are applied to characterize the equilibrium dynamics, entanglement topology, and nonlinear extensional rheology of symmetric ring-linear polymer blends with systematically varied ring fraction $ϕ_R$. Chains with degree of entanglement $Z\approx14$ mixed to produce 10 well-entangled systems with $ϕ_R$ varying from neat linear to neat ring melts. Primitive path analysis are used to visualize and quantify the structure of the composite ring-linear entanglement network. We directly measure the quantity of ring-linear threading and linear-linear entanglement as a function of $ϕ_R$, and identify with simple arguments a ring fraction $ϕ_R\approx0.4$ where the topological constraints of the entanglement network are maximized. These topological analyses are used to rationalize the $ϕ_R$-dependence of ring and linear chain dynamics, conformations, and blend viscosity. Complimentary simulations of startup uniaxial elongation flows demonstrate the extensional stress overshoot observed in recent filament stretching experiments, and characterize how it depends on the blend composition and entanglement topology. The overshoot is driven by an overstretching and recoil of ring polymer conformations that is caused by the convective unthreading of rings from linear chains. This produces significant changes in the entanglement structure of blends that we directly visualize and quantify with primitive path analyses during flow.
The importance of local band effects for ferromagnetism in hole doped La$_2$CuO$_4$
Creators: name: Barbiellini, B.
name: Jarlborg, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Band calculations for supercells of La$_{(2-x)}$Ba$_x$CuO$_4$ show that the rigid band model for doping is less adequate than what is commonly assumed. In particular, weak ferromagnetism (FM) can appear locally around clusters of high Ba concentration. The clustering is important at large dilution and averaged models for magnetism, such as the virtual crystal approximation, are unable to stabilize magnetic moments. These results give a support to the idea that weak FM can be the cause of the destruction of superconductivity at high hole doping.
description: 4 pages, 5 figures, accepted for publication in Physical Review Letters
Analysis of quantum semigroups with GKS--Lindblad generators II. General
Creators: name: Baumgartner, Bernhard
name: Narnhofer, Heide
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Semigroups describing the time evolution of open quantum systems in finite-dimensional spaces have generators of a special form, known as Lindblad generators. These generators and the corresponding processes of time evolution are analyzed, characterized as Decay, Dissipation and Dephasing. In relation to these processes the Hilbert space of the system is equipped with a special structure, a decomposition into a sum of mutually orthogonal subspaces. The complete set of all the stationary states and the asymptotic behavior of the evolutions are presented in detail. Some unusual special facts about invariant operators and symmetries are studied, examples are demonstrated. Perturbation theory for the structure and for the stationary states is discussed and performed in case studies.
description: 32 pages, 2 figures, ESI Report
Studying Pensions Funds Through an Infinite Servers Nodes Network: A Theoretical Problem
Creators: name: Ferreira, Manuel Alberto M.
name: Andrade, Marina
name: Filipe, José António
Publisher: name: arXiv
Year: 2021
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: This study intends to present a representation of a pensions fund through a stochastic network with two infinite servers nodes. With this representation it is allowed to deduce an equilibrium condition of the system with basis on the identity of the random rates expected values, for which the contributions arrive to the fund and the pensions are paid by the fund. In our study a stochastic network is constructed where traffic is represented. This network allows to study the equilibrium in the system and it is admissible to get a balance to a pensions fund. A specific case is studied. When the arrivals from outside at two nodes are according to Poisson processes, the system may be seen as a two nodes network where the first node is a MGinf queue and second a MtGinf queue. For this case in the long term the conditions of equilibrium are given by a very simple formula. In this formula it is established a relationship among the two nodes. Several examples are given in the study.
description: 6 pages and 1 figure
Abella: A System for Reasoning about Relational Specifications
Creators: name: Baelde, David
name: Chaudhuri, Kaustuv
name: Gacek, Andrew
name: Miller, Dale
name: Nadathur, Gopalan
name: Tiu, Alwen
name: Wang, Yuting
Publisher: name: Alma Mater Studiorum - University of Bologna
Year: 2014

description: The Abella interactive theorem prover is based on an intuitionistic logic that allows for inductive and co-inductive reasoning over relations. Abella supports the λ-tree approach to treating syntax containing binders: it allows simply typed λ-terms to be used to represent such syntax and it provides higher-order (pattern) unification, the nabla quantifier, and nominal constants for reasoning about these representations. As such, it is a suitable vehicle for formalizing the meta-theory of formal systems such as logics and programming languages. This tutorial exposes Abella incrementally, starting with its capabilities at a first-order logic level and gradually presenting more sophisticated features, ending with the support it offers to the two-level logic approach to meta-theoretic reasoning. Along the way, we show how Abella can be used prove theorems involving natural numbers, lists, and automata, as well as involving typed and untyped λ-calculi and the π-calculus.
description: Journal of Formalized Reasoning, Vol 7, No 2 (2014): Special Issue: User Tutorials 2
High-Ion Absorption in Seven GRB Host Galaxies at z=2-4: Evidence for both Circumburst Plasma and Outflowing Interstellar Gas
Creators: name: Fox, Andrew J.
name: Ledoux, Cédric
name: Vreeswijk, Paul M.
name: Smette, Alain
name: Jaunsen, Andreas O.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: (Abridged) We use VLT/UVES high-resolution optical spectroscopy of seven GRB afterglows at z_GRB>2 to investigate circumburst and interstellar plasma in the host galaxies. Our sample consists of GRBs 021004, 050730, 050820, 050922C, 060607, 071031, and 080310. Four of these spectra were taken in rapid-response mode, within 30 minutes of the Swift GRB detection. We identify several distinct categories of high-ion absorption at velocities close to z_GRB: (i) Strong high-ion components at z_GRB itself are always seen in OVI, CIV, and SiIV, and usually (in 6 of 7 cases) in NV. We discuss circumburst and interstellar models for the origin of this absorption. Using the non-detection of SIV* toward GRB 050730 together with a UV photo-excitation model, we place a lower limit of 400 pc on the distance of the SIV-bearing gas from the GRB. (ii) Complex, multi-component CIV and SiIV profiles extending over 100-400 km/s around z_GRB are observed in each spectrum; these velocity fields are similar to those measured in damped Lyman-alpha systems at similar redshifts, suggesting a galactic origin. (iii) Asymmetric, blueshifted, absorption-line wings covering 65-140 km/s are seen in the CIV, SiIV, and OVI profiles in 4 of the 7 spectra. The wing kinematics together with the observation that two wings show "Galactic" CIV/SiIV ratios suggest these features trace outflowing ISM gas in the GRB host galaxies. (iv) High-velocity (HV; 500-5000 km/s) components are detected in 6 of the 7 spectra. The HV components show diverse properties. In the cases of GRBs 071031 and 080310, both the ionization level (very high CIV/SiIV ratios and absence of neutral-phase absorption) and the kinematics of the HV components can be explained by Wolf-Rayet winds from the GRB progenitors.
description: 20 pages, 9 figures (7 in color), accepted by A&A, updated with proof corrections including changes to Table 1
Ionization induced plasma grating and its applications in strong-field ionization measurements
Creators: name: Zhang, Chaojie
name: Nie, Zan
name: Wu, Yipeng
name: Sinclair, Mitchell
name: Huang, Chen-Kang
name: Marsh, Ken A.
name: Joshi, Chan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: An ionization-induced plasma grating can be formed by spatially selective ionization of gases by the interference of two intersecting ultra-short laser pulses. The density modulation of a plasma grating can approach unity since the plasma is produced only where the two pulses constructively interfere and ionization does not occur in destructive interference regions. Such a large density modulation leads to efficient Thomson scattering of a second ultra-short probe pulse once the Bragg condition is satisfied. By measuring the scattering efficiency, it is possible to determine the absolute electron density in the plasma grating and thereby deduce the ionization degree for a given neutral gas density. In this paper, we demonstrate the usefulness of this concept by showing two applications: ionization degree measurement of strong-field ionization of atoms and molecules and characterization of extremely low-density gas jets. The former application is of particular interest for ionization physics studies in dense gases where the collision of the ionized electron with neighboring neutrals may become important-sometimes referred to as many-body ionization, and the latter is useful for plasma-based acceleration that requires extremely low-density plasmas.
description: 6 figures
Automata Techniques for Temporal Answer Set Programming
Creators: name: Hahn, Susana
Publisher: name: arXiv
Year: 2021
Subjects: subject: Artificial Intelligence (cs.AI)
subject: Formal Languages and Automata Theory (cs.FL)
subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences

description: Temporal and dynamic extensions of Answer Set Programming (ASP) have played an important role in addressing dynamic problems, as they allow the use of temporal operators to reason with dynamic scenarios in a very effective way. In my Ph.D. research, I intend to exploit the relationship between automata theory and dynamic logic to add automata-based techniques to the ASP solver CLINGO helping us to deal with theses type of problems.
description: In Proceedings ICLP 2021, arXiv:2109.07914
Hydrodynamics of spacetime and vacuum viscosity
Creators: name: Eling, Christopher
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: It has recently been shown that the Einstein equation can be derived by demanding a non-equilibrium entropy balance law dS = dQ/T + dS_i hold for all local acceleration horizons through each point in spacetime. The entropy change dS is proportional to the change in horizon area while dQ and T are the energy flux across the horizon and Unruh temperature seen by an accelerating observer just inside the horizon. The internal entropy production term dS_i is proportional to the squared shear of the horizon and the ratio of the proportionality constant to the area entropy density is \hbar/4π. Here we will show that this derivation can be reformulated in the language of hydrodynamics. We postulate that the vacuum thermal state in the Rindler wedge of spacetime obeys the holographic principle. Hydrodynamic perturbations of this state exist and are manifested in the dynamics of a stretched horizon fluid at the horizon boundary. Using the equations of hydrodynamics we derive the entropy balance law and show the Einstein equation is a consequence of vacuum hydrodynamics. This result implies that \hbar/4πis the shear viscosity to entropy density ratio of the local vacuum thermal state. The value \hbar/4πhas attracted much attention as the shear viscosity to entropy density ratio for all gauge theories with an Einstein gravity dual. It has also been conjectured as the universal lower bound on the ratio. We argue that our picture of the vacuum thermal state is consistent with the physics of the gauge/gravity dualities and then consider possible applications to open questions.
description: 24 pages, 1 figure; v2: references added, typos fixed; v3: clarified and expanded discussion in a few places, added references
Population ecology of yellow-bellied marmots in British Columbia
Creators: name: Donaldson, Judith Lee
Publisher: name: University of British Columbia
Year: 2010

description: Population dynamics of yellow-bellied marmots (Marmota flaviventris) were studied at Watch Lake, British Columbia. I attempted to determine how population size was regulated and compared life history tactics of the Watch Lake populations with those in other areas. Ninety-three percent of adult females and eight percent of yearling females had litters. The mean litter size was 6'. 1 ± .38. The size and weight of a female's litter were negatively correlated with her reproductive effort in the previous year. The annual mortality rate of juveniles was 62%; mortality of yearlings and adults was 33%. Most yearling males and a few yearling females emigrated. . The populations were expanding at a rate of increase of approximately .27. The Watch Lake colonies were generally larger and denser than those reported from other areas. Adult males were territorial throughout the active season. Adult females defended territories during pregnancy and lactation. This is the first report of female territoriality in Marmota flaviventris. Experiments indicated that' (1) adult males caused yearling males to emmigrate and (2) adult females inhibited reproduction of yearling females. I predict that numbers will stabilize through the territorial behaviour of breeding females either reducing the breeding success of females or increasing the emigration rate of yearling females. I describe an experiment to test this hypothesis. Marmot numbers near Watch Lake have been increasing for several decades as new habitat becomes available. Life history tactics of these populations differs from those inhabiting the stable environment of subalpine Colorado. Marmots at Watch Lake suffered greater mortality. They began breeding at a younger age than those in other populations. They allocated relatively more energy to.reproduction, produced larger litters of smaller young, and grew to smaller adult size. These differences are consistent with those predicted by the theory of r- and K- selection for colonizing and stable populations.
Changes
Creators: name: Catalin Berescu
Publisher: name: Zenodo
Year: 2014
Subjects: housing, architecture, Istanbul

description: Architecture Has Its Drama Queens … … but despite the glamorous pictures in glossy architectural magazines (actually, the more posh, the more matte the paper is), the architectural space is rather boring, with even the most dramatic and spectacular works being able to create emotion only for a limited time. The thrill is mainly in the detail, overemphasised by skilled photographers, the types that are brilliant at portraying small, human-scale figures, but helpless when it comes to space. The beautiful lies told by the architectural press do not aim to deceive us but to create drama out of a matter that draws its main qualities from the static and the tectonic, from balance and functionality, from shelter and comfort.
Predictions of Astrometric Jitter for Sun-like Stars. II. Dependence on Inclination, Metallicity, and Active-Region Nesting
Creators: name: Sowmya, K.
name: Nèmec, N. -E.
name: Shapiro, A. I.
name: Işık, E.
name: Witzke, V.
name: Mints, A.
name: Krivova, N. A.
name: Solanki, S. K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Ultra-precise astrometry from the Gaia mission is expected to lead to astrometric detections of more than 20,000 exoplanets in our Galaxy. One of the factors that could hamper such detections is the astrometric jitter caused by the magnetic activity of the planet host stars. In our previous study, we modeled astrometric jitter for the Sun observed equator-on. In this work, we generalize our model and calculate the photocenter jitter as it would be measured by the Gaia and Small-JASMINE missions for stars with solar rotation rate and effective temperature, but with various values of the inclination angle of the stellar rotation axis. In addition, we consider the effect of metallicity and of nesting of active regions (i.e. the tendency of active regions to emerge in the vicinity of each other). We find that, while the jitter of stars observed equator-on does not have any long-term trends and can be easily filtered out, the photocenters of stars observed out of their equatorial planes experience systematic shifts over the course of the activity cycle. Such trends allow the jitter to be detected with continuous measurements, in which case it can interfere with planet detectability. An increase in the metallicity is found to increase the jitter caused by stellar activity. Active-region nesting can further enhance the peak-to-peak amplitude of the photocenter jitter to a level that could be detected by Gaia.
description: 24 pages, 20 figures in the main body and 4 in the appendix, accepted for publication in ApJ
Entanglement genesis under continuous parity measurement
Creators: name: Williams, Nathan S.
name: Jordan, Andrew N.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We examine the stochastic dynamics of entanglement for an uncoupled two-qubit system, undergoing continuous parity measurement. Starting with a fully mixed state, the entanglement is zero for a finite amount of time, when it is suddenly created, which we refer to as entanglement genesis. There can be further entanglement sudden death/birth events culminating in the formation of a fully entangled state. We present numerical investigations of this effect together with statistics of the entanglement genesis time in the weak measurement limit as well as the quantum Zeno limit. An analytic treatment of the physics is presented, aided by the derivation of a simple concurrence equation for Bell basis X-states. The probability of entanglement border crossing and mean first passage times are calculated for the case of measurement dynamics alone. We find that states with almost the same probability of entanglement border crossing can have very different average crossing times. Our results provide insights on the optimization of entanglement generation by measurement.
description: 12 pages, 8 figures
Ultrafast demagnetization in NiCo2O4 thin films probed by time-resolved microscopy
Creators: name: Takahashi, Ryunosuke
name: Tani, Yoshiki
name: Abe, Hirotaka
name: Yamasaki, Minato
name: Suzuki, Ikumi
name: Kan, Daisuke
name: Shimakawa, Yuichi
name: Wadati, Hiroki
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Using a time-resolved magneto-optical Kerr effect (TR-MOKE) microscope, we observed ultrafast demagnetization of inverse-spinel-type NiCo2O4 (NCO) epitaxial thin films of the inverse spinel type ferrimagnet NCO with perpendicular magnetic anisotropy. This microscope uses a pump-probe method, where the sample is pumped at 1030 nm, and magnetic domain images are acquired via MOKE microscopy at 515 nm (the second harmonic). We successfully observed the dynamics of the magnetic domain of the NCO thin film via laser irradiation, and obtained a demagnetization time constant of approximately 0.4 ps. This time constant was significantly smaller than the large time constants reported for other half-metallic oxides. These results, combined with the results of our x-ray photoemission spectroscopy study, indicate that this NCO thin film is a ferrimagnetic metal whose electronic structure deviates from the theoretically predicted half-metallic one.
description: 5 pages, 5 figures
Spin and orbital angular momentum in gauge theories: Nucleon spin structure and multipole radiation revisited
Creators: name: Chen, Xiang-Song
name: Lü, Xiao-Fu
name: Sun, Wei-Min
name: Wang, Fan
name: Goldman, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We address and solve the long-standing gauge-invariance problem of the nucleon spin structure. Explicitly gauge-invariant spin and orbital angular momentum operators of quarks and gluons are obtained. This was previously thought to be an impossible task, and opens a more promising avenue towards the understanding of the nucleon spin. Our research also justifies the traditional use of the canonical, gauge-dependent angular momentum operators of photons and electrons in the multipole-radiation analysis and labeling of atomic states; and sheds much light on the related energy-momentum problem in gauge theories, especially in connection with the nucleon momentum.
description: 4 pages, no figure
X-ray refractive index of laser-dressed atoms
Creators: name: Buth, Christian
name: Santra, Robin
Publisher: name: arXiv
Year: 2008
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We investigated the complex index of refraction in the x-ray regime of atoms in laser light. The laser (intensity up to 10^13 W/cm^2, wavelength 800nm) modifies the atomic states but, by assumption, does not excite or ionize the atoms in their electronic ground state. Using quantum electrodynamics, we devise an ab initio theory to calculate the dynamic dipole polarizability and the photoabsorption cross section, which are subsequently used to determine the real and imaginary part, respectively, of the refractive index. The interaction with the laser is treated nonperturbatively; the x-ray interaction is described in terms of a one-photon process. We numerically solve the resolvents involved using a single-vector Lanczos algorithm. Finally, we formulate rate equations to copropagate a laser and an x-ray pulse through a gas cell. Our theory is applied to argon. We study the x-ray polarizability and absorption near the argon K edge over a large range of dressing-laser intensities. We find electromagnetically induced transparency (EIT) for x rays on the Ar 1s --> 4p pre-edge resonance. We demonstrate that EIT in Ar allows one to imprint the shape of an ultrafast laser pulse on a broader x-ray pulse (duration 100ps, photon energy 3.2keV). Our work thus opens new opportunities for research with hard x-ray sources.
description: 12 pages, 10 figures, 1 table, RevTeX4, corrected typos