cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Vacuum Ambiguity in de Sitter Space at Strong Coupling
Creators: name: Hutasoit, Jimmy A.
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It is well known that in the weak coupling regime, quantum field theories in de Sitter space do not have a unique vacuum, but a class of vacua parametrized by a complex parameter $α$, i.e., the so-called $α$-vacua. In this article, using gauge/gravity duality, we calculate the symmetric two-point function of strongly coupled ${\cal N}=4$ supersymmetric Yang-Mills theory on $dS_3$. We find that there is a class of de Sitter invariant vacua, parametrized by a set of complex parameters $\{α_ν\}$.
description: 17 pages in JHEP style, references added
CIFRA National Survey: Uruguay October 2013
Creators: name: CIFRA, In Bogliaccini, Juan, And Queirolo Rosario Laboratorio De Opinión Pública And Redes Sociales En Uruguay Collection (Social Networks And Public Opinion Lab Collection)
Publisher: name: Roper Center for Public Opinion Research
Year: 2021

description: Main problems in country; military police functions; likability of political leaders; approval of President José Mujica; approval of district mayor; priorities of district government; attitudes towards political parties; interest in politics; approval of labor unions; government declared essential services; voting in primary elections; political spectrum position; past voting history; disputes over pulp mills; trust in different occupations; influence of Pope Francis; economic situation of the country; comparison with parents' lives; legalization of marijuana; mayoral elections. National Agency for Research and Innovation (ANII) Collection.
An Entropy Threshold for Strong H-alpha and Radio Emission in the Cores of Galaxy Clusters
Creators: name: Cavagnolo, Kenneth W.
name: Donahue, Megan
name: Voit, G. Mark
name: Sun, Ming
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Our Chandra X-ray Observatory archival study of intracluster entropy in a sample of 222 galaxy clusters shows that H-alpha and radio emission from the brightest cluster galaxy are much more pronounced when the cluster's core gas entropy is < 30 keV cm^2. The prevalence of H-alpha emission below this threshold indicates that it marks a dichotomy between clusters that can harbor multiphase gas and star formation in their cores and those that cannot. The fact that strong central radio emission also appears below this boundary suggests that AGN feedback turns on when the intracluster medium starts to condense, strengthening the case for AGN feedback as the mechanism that limits star formation in the Universe's most luminous galaxies.
description: Submitted to ApJ Letters
Characterising Solar Magnetic Reconnection in Confined and Eruptive Flares
Creators: name: Balamuralikrishna, Kanniah
name: Soo, John Y. H.
name: Tahrin, Norhaslinda Mohamed
name: Aziz, Abdul Halim Abdul
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Magnetic reconnection is a fundamental mechanism through which energy stored in magnetic fields is released explosively on a massive scale, they could be presented as eruptive or confined flares, depending on their association with coronal mass ejections (CMEs). Several previous works have concluded that there is no correlation between flare duration and flare class, however, their sample sizes are skewed towards B and C classes; they hardly represent the higher classes. Therefore, we studied a sample without extreme events in order to determine the correlation between flare duration and flare type (confined and eruptive). We examined $33$ flares with classes between M5 to X5 within $45^{\circ}$ of the disk centres, using data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI). We find that the linear correlation between flare class against flare duration by full width half maximum (FWHM) in general is weak ($r=0.19$); however, confined flares have a significant correlation ($r=0.58$) compared to eruptive types ($r=0.08$). Also, the confined M class flares' average duration is less than half of the eruptive flares. Similarly, confined flares have a higher correlation ($r=0.89$) than eruptive flares ($r=0.60$) between flare classes against magnetic reconnection flux. In this work, a balanced sample size between flare types is an important strategy for obtaining a reliable quantitative comparison.
description: 26 pages, 11 figures
Additional file 1: of miR-519a enhances chemosensitivity and promotes autophagy in glioblastoma by targeting STAT3/Bcl2 signaling pathway
Creators: name: Li, Hong
name: Chen, Lei
name: Li, Jun-jie
name: Zhou, Qiang
name: Huang, Annie
name: Liu, Wei-wen
name: Wang, Ke
name: Gao, Liang
name: Qi, Song-tao
name: Lu, Yun-tao
Publisher: name: figshare
Year: 2018
Subjects: subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: Genetics
subject: Molecular Biology
subject: Biological Sciences not elsewhere classified
subject: Developmental Biology
subject: Infectious Diseases
subject: FOS: Health sciences

description: Table S1. Sequences of siRNAs and miRNA used in this study. (DOCX 58Â kb)
Semispectral measures as convolutions and their moment operators
Creators: name: Kiukas, Jukka
name: Lahti, Pekka
name: Ylinen, Kari
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The moment operators of a semispectral measure having the structure of the convolution of a positive measure and a semispectral measure are studied, with paying attention to the natural domains of these unbounded operators. The results are then applied to conveniently determine the moment operators of the Cartesian margins of the phase space observables.
description: 7 pages
Die Toolbox Datenkompetenz als Baustein des FDM-Kompetenzerwerbs
Creators: name: Biedermann, Christian
Publisher: name: Zenodo
Year: 2024
Subjects: SaxFDM Tagung 2024
SaxFDM
InfAI
Toolbox Datenkompetenz

description: Datenkompetenz als eine zentrale Querschnittskompetenz mit wachsender Bedeutung in der Wissensgesellschaft des 21. Jahrhunderts ist das Anliegen der Toolbox Datenkompetenz (TBDK). Dieses seit 2022 vom BMBF geförderte Forschungs- und Entwicklungsprojekt hat eine Lern- und Weiterbildungsplattform geschaffen, die den Lebenszyklus von Daten fokussiert und alle Facetten der Lehrund Lerninhalte bezüglich Datenkompetenz abzudecken versucht. Die dazu notwendige Vielfalt desAngebots geeigneter Bildungsressourcen wird durch das F&E-Team der TBDK sukzessive in den Blickgenommen und erweitert. Zu diesem Angebot zählen:

Workspaces (für individuelle und kollaborative Arbeit an Datenprojekten),

Datasets (als Grundlage eigener Projekte und praktischer Anwendung von Wissen),

Kurse aus der Toolbox Lernwelt (für alle Wissensstufen und Themengebiete),

Partnerkurse (von Expert:innen kuratierte OER),

sowie Data Challenges (zum Testen des eigenen Könnens oder Hosting-Möglichkeit)
The impact of floods on firms' performance
Creators: name: Coelli, Federica
name: Manasse, Paolo
Publisher: name: Alma Mater Studiorum - Università di Bologna
Year: 2014
Subjects: SECS-P/01 Economia politica

description: We estimate the short-run impact of a major flood that hit the region of Veneto in 2010 on firms' performance. Using firm level data and a difference in difference approach we compare the value added growth of hit firms to the one of a control group of companies that are not exposed to the flood. The results indicate that the value added growth of affected firms is 6.9% higher two years after the flood. We further investigate the role of aid transfers in the aftermath of the disaster event. Considering both the flood and the aid treatment, we construct four mutually exclusive and exhaustive groups. The results indicate that, among firms exposed to the flood, both the ones that benefit from financial aid and the ones that don't grow faster than the reference groups of firms that neither are exposed to the flood, nor receive financial aid. We also find a 2% additional growth effect that is attributable to the contribution of aid in the recovery phase.
Hierarchical zonotopal spaces
Creators: name: Holtz, Olga
name: Ron, Amos
name: Xu, Zhiqiang
Publisher: name: arXiv
Year: 2009
Subjects: subject: Commutative Algebra (math.AC)
subject: Classical Analysis and ODEs (math.CA)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 13F20, 13A02, 16W50, 16W60, 47F05, 47L20, 05B20, 05B35, 05B45, 05C50, 52B05, 52B12, 52B20, 52C07, 52C35, 41A15, 41A63

description: Zonotopal algebra interweaves algebraic, geometric and combinatorial properties of a given linear map X. Of basic significance in this theory is the fact that the algebraic structures are derived from the geometry (via a non-linear procedure known as "the least map"), and that the statistics of the algebraic structures (e.g., the Hilbert series of various polynomial ideals) are combinatorial, i.e., computable using a simple discrete algorithm known as "the valuation function". On the other hand, the theory is somewhat rigid since it deals, for the given X, with exactly two pairs each of which is made of a nested sequence of three ideals: an external ideal (the smallest), a central ideal (the middle), and an internal ideal (the largest). In this paper we show that the fundamental principles of zonotopal algebra as described in the previous paragraph extend far beyond the setup of external, central and internal ideals by building a whole hierarchy of new combinatorially defined zonotopal spaces.
description: 21 pages; final version; to appear in Trans. Amer. Math. Soc.
Fault-Tolerant Computing With Biased-Noise Superconducting Qubits
Creators: name: Aliferis, Panos
name: Brito, Frederico
name: DiVincenzo, David P.
name: Preskill, John
name: Steffen, Matthias
name: Terhal, Barbara M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We present a universal scheme of pulsed operations for the IBM oscillator-stabilized flux qubit comprising the CPHASE gate, single-qubit preparations and measurements. Based on numerical simulations, we argue that the error rates for these operations can be as low as about .5% and that noise is highly biased, with phase errors being stronger than all other types of errors by a factor of nearly 10^3. In contrast, the design of a CNOT gate for this system with an error rate of less than about 1.2% seems extremely challenging. We propose a special encoding which exploits the noise bias allowing us to implement a logical CNOT gate where phase errors and all other types of errors have nearly balanced rates of about .4%. Our results illustrate how the design of an encoding scheme can be adjusted and optimized according to the available physical operations and the particular noise characteristics of experimental devices.
description: 15 pages, 7 figures
Estate Planning for Farm Families: Updated for 2014
Creators: name: Lynch, Lori
name: Goeringer, Paul
name: Musser, Wes
Publisher: name: Digital Repository at the University of Maryland
Year: 2014
Subjects: estate planning
death tax
inheritance tax
estate tax
will
trust
business organization

description: Updated for Maryland estate tax changes starting in 2014.  This fact sheet provides an overview of the estate planning process
description: USDA-RMA, Maryland Department of Ag, and University of Maryland Extension
title: ÐÐ²ÑÐ¾Ð¼Ð°ÑÐ¸Ð·Ð°ÑÐ¸Ñ Ð¿Ð¾Ð¸ÑÐºÐ° Ð´ÐµÑÐ°Ð»Ð¸-Ð°Ð½Ð°Ð»Ð¾Ð³Ð° Ð² Ð¡ÐÐÐ Ð¢Ð
title: Automation of analog part search in CADRE TP
Creators: name: ÐÐ°Ð¿ÑÐµÐ², ÐÐ»ÐµÐºÑÐ°Ð½Ð´Ñ
name: Ð¢ÑÐµÑÑÑÐºÐ¾Ð², Ð¡ÐµÑÐ³ÐµÐ¹
name: "Ð¡Ð¾Ð²ÑÐµÐ¼ÐµÐ½Ð½Ð¾Ðµ Ð¼Ð°ÑÐ¸Ð½Ð¾ÑÑÑÐ¾ÐµÐ½Ð¸Ðµ: Ð½Ð°ÑÐºÐ° Ð¸ Ð¾Ð±ÑÐ°Ð·Ð¾Ð²Ð°Ð½Ð¸Ðµ", Ð¼ÐµÐ¶Ð´ÑÐ½Ð°ÑÐ¾Ð´Ð½Ð°Ñ Ð½Ð°ÑÑÐ½Ð°Ñ ÐºÐ¾Ð½ÑÐµÑÐµÐ½ÑÐ¸Ñ (13; 2024; Ð¡Ð°Ð½ÐºÑ-ÐÐµÑÐµÑÐ±ÑÑÐ³)
Publisher: name: ÐÐÐÐÐ¢ÐÐ¥-ÐÐ ÐÐ¡Ð¡
Year: 2024
Subjects: ÐÐ°ÑÐ¸Ð½Ð¾ÑÑÑÐ¾ÐµÐ½Ð¸Ðµ
ÐÐ²ÑÐ¾Ð¼Ð°ÑÐ¸Ð·Ð¸ÑÐ¾Ð²Ð°Ð½Ð½ÑÐµ ÑÐ¸ÑÑÐµÐ¼Ñ Ð¿ÑÐ¾ÐµÐºÑÐ¸ÑÐ¾Ð²Ð°Ð½Ð¸Ñ
ÑÐ¸ÑÑÐµÐ¼Ð° Ð°Ð²ÑÐ¾Ð¼Ð°ÑÐ¸Ð·Ð¸ÑÐ¾Ð²Ð°Ð½Ð½Ð¾Ð³Ð¾ Ð¿ÑÐ¾ÐµÐºÑÐ¸ÑÐ¾Ð²Ð°Ð½Ð¸Ñ ÑÐµÑ Ð½Ð¾Ð»Ð¾Ð³Ð¸ÑÐµÑÐºÐ¸Ñ Ð¿ÑÐ¾ÑÐµÑÑÐ¾Ð²
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ÑÐµÑ Ð½Ð¾Ð»Ð¾Ð³Ð¸ÑÐµÑÐºÐ°Ñ Ð¿Ð¾Ð´Ð³Ð¾ÑÐ¾Ð²ÐºÐ° Ð¿ÑÐ¾Ð¸Ð·Ð²Ð¾Ð´ÑÑÐ²Ð°
system of automated design of technological processes
automation
information and search system of technological purpose
technological preparation of production

description: Ð ÑÐ°Ð±Ð¾ÑÐµ ÑÐ°ÑÑÐ¼Ð¾ÑÑÐµÐ½Ñ Ð²Ð¾Ð¿ÑÐ¾ÑÑ Ð¿ÑÐ¾ÐµÐºÑÐ¸ÑÐ¾Ð²Ð°Ð½Ð¸Ñ ÑÐµÑÐ½Ð¾Ð»Ð¾Ð³Ð¸ÑÐµÑÐºÐ¸Ñ Ð¿ÑÐ¾ÑÐµÑÑÐ¾Ð² Ð² ÑÐ¾Ð²ÑÐµÐ¼ÐµÐ½Ð½ÑÑ ÑÐ¸ÑÑÐµÐ¼Ð°Ñ Ð°Ð²ÑÐ¾Ð¼Ð°ÑÐ¸Ð·Ð¸ÑÐ¾Ð²Ð°Ð½Ð½Ð¾Ð³Ð¾ Ð¿ÑÐ¾ÐµÐºÑÐ¸ÑÐ¾Ð²Ð°Ð½Ð¸Ñ ÑÐµÑÐ½Ð¾Ð»Ð¾Ð³Ð¸ÑÐµÑÐºÐ¸Ñ Ð¿ÑÐ¾ÑÐµÑÑÐ¾Ð² (Ð¡ÐÐÐ  Ð¢Ð). ÐÑÐ»Ð¸ Ð²ÑÑÐ²Ð»ÐµÐ½Ñ Ð½ÐµÐ´Ð¾ÑÑÐ°ÑÐºÐ¸ Ð² Ð¿ÑÐ¸Ð¼ÐµÐ½ÐµÐ½Ð¸Ð¸ Ð¸Ð¼ÐµÑÑÐ¸ÑÑÑ Ð¼ÐµÑÐ¾Ð´Ð¾Ð² Ð² Ð¿ÑÐ¾Ð¸Ð·Ð²Ð¾Ð´ÑÑÐ²Ðµ ÑÐ¸ÑÐ¾ÐºÐ¾Ð³Ð¾ ÑÐ¿ÐµÐºÑÑÐ° Ð¸Ð·Ð³Ð¾ÑÐ°Ð²Ð»Ð¸Ð²Ð°ÐµÐ¼ÑÑ Ð¿ÑÐ¾Ð´ÑÐºÑÐ¾Ð² Ð¸ÑÐ¿Ð¾Ð»ÑÐ·ÑÑÑÐ¸Ñ ÑÐ¾Ð²ÑÐµÐ¼ÐµÐ½Ð½ÑÐµ Ð¡ÐÐÐ  Ð¢Ð. ÐÑÐ» Ð¿ÑÐ¾Ð²ÐµÐ´ÐµÐ½ Ð°Ð½Ð°Ð»Ð¸Ð· Ð¸Ð½ÑÐ¾ÑÐ¼Ð°ÑÐ¸Ð¾Ð½Ð½Ð¾Ð¹ ÑÐ¸ÑÑÐµÐ¼Ñ Ð¿Ð¾Ð¸ÑÐºÐ° ÑÐµÑÐ½Ð¾Ð»Ð¾Ð³Ð¸ÑÐµÑÐºÐ¾Ð³Ð¾ Ð½Ð°Ð·Ð½Ð°ÑÐµÐ½Ð¸Ñ Ð¸ Ð±ÑÐ»Ð¸ Ð¿ÑÐµÐ´Ð»Ð¾Ð¶ÐµÐ½Ñ ÑÐ¿Ð¾ÑÐ¾Ð±Ñ Ð¿Ð¾ ÐµÐµ ÑÐ»ÑÑÑÐµÐ½Ð¸Ñ Ð¸ Ð¿Ð¾Ð²ÑÑÐµÐ½Ð¸Ñ ÑÑÑÐµÐºÑÐ¸Ð²Ð½Ð¾ÑÑÐ¸ ÑÑÐ°Ð¿Ð° ÑÐµÑÐ½Ð¾Ð»Ð¾Ð³Ð¸ÑÐµÑÐºÐ¾Ð¹ Ð¿Ð¾Ð´Ð³Ð¾ÑÐ¾Ð²ÐºÐ¸ Ð¿ÑÐ¾Ð¸Ð·Ð²Ð¾Ð´ÑÑÐ²Ð°.
description: The article considers design of technological processes in modern systems of automated design of technological processes (CAPP). Shortcomings were identified in the application of available techniques in the production of a wide range of manufactured products using modern CAPP. An analysis of the information system of technological search was carried out and ways to improve it and increase the efficiency of the stage of technological preparation of production were proposed.
Diffractive Higgs boson photoproduction in $γp$ process
Creators: name: Ducati, M. B. Gay
name: Silveira, G. G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We explore an alternative process for the diffractive Higgs boson production in peripheral pp collisions arising from Double Pomeron Exchange in photon-proton interaction. We introduce the impact factor formalism in order to enable the gluon ladder exchange in the photon-proton subprocess, and to permit the central Higgs production. The event rate for the diffractive Higgs production in central rapidity is estimated to be about 0.6 pb at Tevatron and LHC energies. This result is higher than predictions from other approaches for diffractive Higgs production, showing that the alternative production process leads to an enhanced signal for the detection of the Higgs boson at hadron colliders. Our results are compared to those obtained from a similar approach proposed by the Durham group. In this way we may examine the future developments in its application to pp and AA collisions.
description: 12 pages, 12 figures, corrected typos and grammar
Topological geon black holes in Einstein-Yang-Mills theory
Creators: name: Kottanattu, George T.
name: Louko, Jorma
Publisher: name: arXiv
Year: 2010
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We construct topological geon quotients of two families of Einstein-Yang-Mills black holes. For Kuenzle's static, spherically symmetric SU(n) black holes with n>2, a geon quotient exists but generically requires promoting charge conjugation into a gauge symmetry. For Kleihaus and Kunz's static, axially symmetric SU(2) black holes a geon quotient exists without gauging charge conjugation, and the parity of the gauge field winding number determines whether the geon gauge bundle is trivial. The geon's gauge bundle structure is expected to have an imprint in the Hawking-Unruh effect for quantum fields that couple to the background gauge field.
description: 27 pages. v3: Presentation expanded. Minor corrections and additions
Discovery of a 552 Hz burst oscillation in the low-mass X-ray binary EXO 0748-676
Creators: name: Galloway, Duncan K.
name: Lin, Jinrong
name: Chakrabarty, Deepto
name: Hartman, Jacob M.
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We report the detection of pulsations at 552 Hz in the rising phase of two type-I (thermonuclear) X-ray bursts observed from the accreting neutron star EXO 0748-676 in 2007 January and December, by the Rossi X-ray Timing Explorer. The fractional amplitude was 15% (rms). The dynamic power density spectrum for each burst revealed an increase in frequency of approx. 1-2 Hz while the oscillation was present. The frequency drift, the high significance of the detections and the almost identical signal frequencies measured in two bursts separated by 11 months, confirms this signal as a burst oscillation similar to those found in 13 other sources to date. We thus conclude that the spin frequency in EXO 0748-676 is within a few Hz of 552 Hz, rather than 45 Hz as was suggested from an earlier signal detection by Villarreal & Strohmayer (2004). Consequently, Doppler broadening must significantly affect spectral features arising from the neutron star surface, so that the narrow absorption features previously reported from an XMM-Newton spectrum could not have arisen there. The origin of both the previously reported 45 Hz oscillation and the X-ray absorption lines is now uncertain.
description: 5 pages, 2 figures, accepted for Astrophysical Journal Letters. Minor changes following referees report
Conduction and the Star-Formation Threshold in Brightest Cluster Galaxies
Creators: name: Voit, G. M.
name: Cavagnolo, K. W.
name: Donahue, M.
name: Rafferty, D. A.
name: McNamara, B. R.
name: Nulsen, P. E. J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Current models of galaxy evolution suggest that feedback from active galactic nuclei is needed to explain the high-luminosity cutoff in the galaxy luminosity function. Exactly how an AGN outflow couples with the ambient medium and suppresses star formation remains poorly understood. However, we have recently uncovered an important clue to how that coupling might work. Observations of H-alpha emission and blue light from the universe's most luminous galaxies, which occupy the centers of galaxy clusters, show that star formation happens only if the minimum specific entropy of the intracluster gas is less than 30 keV cm^2. Here we suggest that this threshold for star formation is set by the physics of electron thermal conduction, implying that conduction is critical for channeling AGN energy input toward incipient star-forming regions and limiting the progress of star formation.
description: Accepted to ApJ Letters, 5 pages, 4 figures
Millikelvin scanning tunneling microscope at 20/22 T with a graphite enabled stick-slip approach and an energy resolution below 8$μ$eV: Application to conductance quantization at 20 T in single atom point contacts of Al and Au
Creators: name: Lomana, Marta Fernández
name: Wu, Beilun
name: Martín-Vega, Francisco
name: Barquilla, Raquel Sánchez
name: Montoya, Rafael Álvarez
name: Castilla, José María
name: Navarrete, José
name: Marijuan, Juan Ramón
name: Herrera, Edwin
name: Suderow, Hermann
name: Guillamón, Isabel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: We describe a scanning tunneling microscope (STM) that operates at magnetic fields up to 22 Tesla and temperatures down to 80 mK. We discuss the design of the STM head, with an improved coarse approach, the vibration isolation system, and efforts to improve the energy resolution using compact filters for multiple lines. We measure the superconducting gap and Josephson effect in Aluminum and show that we can resolve features in the density of states as small as 8\,$μ$eV. We measure the quantization of conductance in atomic size contacts and make atomic resolution and density of states images in the layered material 2H-NbSe$_2$. The latter experiments are performed by continuously operating the STM at magnetic fields of 20 T in periods of several days without interruption.
description: 16 pages, 12 figures
Approximate Hamiltonian Statistics in One-dimensional Driven Dissipative Many-Particle Systems
Creators: name: Treiber, Martin
name: Helbing, Dirk
Publisher: name: arXiv
Year: 2008
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: This contribution presents a derivation of the steady-state distribution of velocities and distances of driven particles on a onedimensional periodic ring. We will compare two different situations: (i) symmetrical interaction forces fulfilling Newton's law of "actio = reactio" and (ii) asymmetric, forwardly directed interactions as, for example in vehicular traffic. Surprisingly, the steady-state velocity and distance distributions for asymmetric interactions and driving terms agree with the equilibrium distributions of classical many-particle systems with symmetrical interactions, if the system is large enough. This analytical result is confirmed by computer simulations and establishes the possibility of approximating the steady state statistics in driven many-particle systems by Hamiltonian systems. Our finding is also useful to understand the various departure time distributions of queueing systems as a possible effect of interactions among the elements in the respective queue [D. Helbing et al., Physica A 363, 62 (2006)].
description: 11 pages, 7 figures, submitted to The European Physical Journal B
Landau-Zener problem with waiting at the minimum gap and related quench dynamics of a many-body system
Creators: name: Divakaran, Uma
name: Dutta, Amit
name: Sen, Diptiman
Publisher: name: arXiv
Year: 2009
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We discuss a technique for solving the Landau-Zener (LZ) problem of finding the probability of excitation in a two-level system. The idea of time reversal for the Schrodinger equation is employed to obtain the state reached at the final time and hence the excitation probability. Using this method, which can reproduce the well-known expression for the LZ transition probability, we solve a variant of the LZ problem which involves waiting at the minimum gap for a time t_w; we find an exact expression for the excitation probability as a function of t_w. We provide numerical results to support our analytical expressions. We then discuss the problem of waiting at the quantum critical point of a many-body system and calculate the residual energy generated by the time-dependent Hamiltonian. Finally we discuss possible experimental realizations of this work.
description: 6 pages including 3 figures; significantly expanded -- this is the published version
Adiabatic Quantum Computation with a 1D projector Hamiltonian
Creators: name: Tulsi, Avatar
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Adiabatic quantum computation is based on the adiabatic evolution of quantum systems. We analyse a particular class of qauntum adiabatic evolutions where either the initial or final Hamiltonian is a one-dimensional projector Hamiltonian on the corresponding ground state. The minimum energy gap which governs the time required for a successful evolution is shown to be proportional to the overlap of the ground states of the initial and final Hamiltonians. We show that such evolutions exhibit a rapid crossover as the ground state changes abruptly near the transition point where the energy gap is minimum. Furthermore, a faster evolution can be obtained by performing a partial adiabatic evolution within a narrow interval around the transition point. These results generalize and quantify earlier works.
description: revised version
Stable magnetic equilibria and their evolution in the upper main sequence, white dwarfs, and neutron stars
Creators: name: Reisenegger, Andreas
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: [abbreviated] Long-lived, large-scale magnetic field configurations exist in upper main sequence, white dwarf, and neutron stars. Externally, these fields have a strong dipolar component, while their internal structure and evolution are uncertain, but highly relevant for several problems in stellar and high-energy astrophysics. We discuss the main properties expected for the stable magnetic configurations in these stars from physical arguments, and how these properties may determine the modes of decay of these configurations. Stable magneto-hydrostatic equilibria are likely to exist in stars whenever the matter in their interior is stably stratified (not barotropic). These equilibria are not force-free and not required to satisfy the Grad-Shafranov equation, but they do involve both toroidal and poloidal field components. We argue that the main mode of decay for these configurations are processes that lift the constraints set by stable stratification, such as heat diffusion in main-sequence envelopes and white dwarfs, and beta decays or particle diffusion in neutron stars. In the former, heat diffusion is not fast enough to make these equilibria evolve over the stellar lifetime. In neutron stars, a strong enough field might decay by overcoming the compositional stratification through beta decays (at the highest field strengths) or through ambipolar diffusion (for somewhat weaker fields). These processes convert magnetic energy to thermal energy, and they occur at significant rates only once the latter is smaller than the former, and therefore they substantially delay the cooling of the neutron star, while slowly decreasing its magnetic energy.
description: 11 pages, 1 figure, accepted by A&A. This version has been revised according to the referee's and editor's comments and suggestions, and a few signs were corrected in sec. 2.4
Intrinsic leakage of the Josephson flux qubit and breakdown of the two-level approximation for strong driving
Creators: name: Ferron, Alejandro
name: Dominguez, Daniel
Publisher: name: arXiv
Year: 2009
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Solid state devices for quantum bit computation (qubits) are not perfect isolated two-level systems, since additional higher energy levels always exist. One example is the Josephson flux qubit, which consists on a mesoscopic SQUID loop with three Josephson junctions operated at or near a magnetic flux of half quantum. We study intrinsic leakage effects, i.e., direct transitions from the allowed qubit states to higher excited states of the system during the application of pulses for quantum computation operations. The system is started in the ground state and rf- magnetic field pulses are applied at the qubit resonant frequency with pulse intensity $f_p$. A perturbative calculation of the average leakage for small $f_p$ is performed for this case, obtaining that the leakage is quadratic in $f_p$, and that it depends mainly on the matrix elements of the supercurrent. Numerical simulations of the time dependent Schrödinger equation corresponding to the full Hamiltonian of this device were also performed. From the simulations we obtain the value of $f_p$ above which the two-level approximation breaks down, and we estimate the maximum Rabi frequency that can be achieved. We study the leakage as a function of the ratio $α$ among the Josephson energies of the junctions of the device, obtaining the best value for minimum leakage ($α\approx0.85$). The effects of flux noise on the leakage are also discussed.
description: Final improved version. Some figures have changed with new results added. To be published in Phys. Rev. B
Local causal structures, Hadamard states and the principle of local covariance in quantum field theory
Creators: name: Dappiaggi, Claudio
name: Pinamonti, Nicola
name: Porrmann, Martin
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In the framework of the algebraic formulation, we discuss and analyse some new features of the local structure of a real scalar quantum field theory in a strongly causal spacetime. In particular we use the properties of the exponential map to set up a local version of a bulk-to-boundary correspondence. The bulk is a suitable subset of a geodesic neighbourhood of any but fixed point p of the underlying background, while the boundary is a part of the future light cone having p as its own tip. In this regime, we provide a novel notion for the extended *-algebra of Wick polynomials on the said cone and, on the one hand, we prove that it contains the information of the bulk counterpart via an injective *-homomorphism while, on the other hand, we associate to it a distinguished state whose pull-back in the bulk is of Hadamard form. The main advantage of this point of view arises if one uses the universal properties of the exponential map and of the light cone in order to show that, for any two given backgrounds M and M' and for any two subsets of geodesic neighbourhoods of two arbitrary points, it is possible to engineer the above procedure such that the boundary extended algebras are related via a restriction homomorphism. This allows for the pull-back of boundary states in both spacetimes and, thus, to set up a machinery which permits the comparison of expectation values of local field observables in M and M'.
description: 42 pages, xy package is used, typos corrected, clarifications added
A Spin-1 Top Quark Superpartner
Creators: name: Cai, Haiying
name: Cheng, Hsin-Chia
name: Terning, John
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We construct a supersymmetric model where the left-handed top and bottom quarks are mainly the gauginos of a vector supermultiplet and hence their superpartners are spin-1. The right-handed top quark is unified with the Higgs, the top Yukawa arises from the gaugino coupling.
description: 4 pages, 2 figures, published version, added comments on baryon number conservation and corrected statements about the Higgs quartic coupling
Analysis of extremely low signal-to-noise ratio data from INTEGRAL/PICsIT
Creators: name: Lubinski, Piotr
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The PICsIT detector onboard the INTEGRAL satellite was designed to provide information about emission in the soft gamma-ray band for many bright sources. Due to strong and variable instrumental background, only 4 objects have been detected so far using standard software. The moderate sensitivity of PICsIT can be compensated for in the case of many objects by adopting a long exposure time, thanks to INTEGRAL's large field of view. With angular resolution far higher than that of all other instruments operating in a similar energy band, PICsIT is suitable for fields too crowded or too significantly affected by Galactic diffuse emission. Therefore, it is desirable to improve the spectral extraction software to both obtain more reliable results and enlarge the number of objects that can be studied. The new PICsIT spectral extraction method is based on three elements: careful modelling of the background, an energy-dependent pixel-illumination function, and the computation of the probability density of the source count rate. The most important element is the proper treatment of the Poisson-distributed data, developed within a Bayesian framework. The new method was tested extensively on both a large true data set and simulated data. Results assumed in simulations were reproduced perfectly, without any bias and with high precision. Count rates measured for Crab were far more stable than those obtained with the standard software. For weaker sources, the new method produced spectra of far higher quality and allows us to detect at least 8 additional objects. Comparison with other INTEGRAL instruments demonstrated that PICsIT is well calibrated and provides valuable information about the continuum emission in the 250 keV -- 1 MeV band.
description: Latex, 21 pages, 24 eps figures, final version, A&A, in print
Flavor changing neutral currents in 331 models
Creators: name: Cabarcas, J. M.
name: Dumm, D. Gomez
name: Martinez, R.
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We carry out a general analysis of tree level flavor changing neutral currents in the context of 331 models, considering arbitrary quark and gauge boson mixing matrices. The results are applied to definite textures of quark mass matrices, and differences between various 331 scenarios are pointed out.
description: 11 pages, no figures. Sec. IV enlarged, 1 reference added
A Re-evaluation of Evidence for Light Neutral Bosons in Nuclear Emulsions
Creators: name: de Boer, F. W. N.
name: Fields, C. A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Electron-positron pair-production data obtained by bombardment of emulsion detectors with either cosmic rays or projectiles with mass between one and 207 and kinetic energies between 18 GeV and 32 TeV have been re-analysed using a consistent and conservative model of the background from electromagnetic pair conversion. The combined data yield a spectrum of putative neutral bosons decaying to e+e- pairs, with masses between 3 and 20 MeV/c^2 and femtosecond lifetimes. The statistical significance against background for these "X-bosons" varies between 2 and 8 sigma. The cross-section for direct production of X-bosons increases slowly with projectile energy, remaining over 1,000 times smaller the the pion production cross-section.
description: major revision with improved figures; accepted by Int J Mod Phys E
Euler-Lagrange models with complex currents of three-phase electrical machines and observability issues
Creators: name: Basic, Duro
name: Malrait, Francois
name: Rouchon, Pierre
Publisher: name: arXiv
Year: 2008
Subjects: subject: Optimization and Control (math.OC)
subject: Classical Physics (physics.class-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: A new Lagrangian formulation with complex currents is developed and yields a direct and simple method for modeling three-phase permanent-magnet and induction machines. The Lagrangian is the sum a mechanical one and of a magnetic one. This magnetic Lagrangian is expressed in terms of rotor angle, complex stator and rotor currents. A complexification procedure widely used in quantum electrodynamic is applied here in order to derive the Euler-Lagrange equations with complex stator and rotor currents. Such complexification process avoids the usual separation into real and imaginary parts and simplifies notably the calculations. Via simple modifications of such magnetic Lagrangians we derive new dynamical models describing permanent-magnet machines with both saturation and saliency, and induction machines with both magnetic saturation and space harmonics. For each model we also provide its Hamiltonian thus its magnetic energy. This energy is also expressed with complex currents and can be directly used in Lyapunov and/or passivity based control. Further, we briefly investigate the observability of this class of Euler-Lagrange models, in the so-called sensorless case when the measured output is the stator current and the load torque is constant but unknown. For all the dynamical models obtained via such variational principles, we prove that their linear tangent systems are unobservable around a one-dimensional family of steady-states attached to the same constant stator voltage and current. This negative result explains why sensorless control of three-phase electrical machines around zero stator frequency remains yet a difficult control problem.
description: Revised version. Submitted for publication
The probability distribution of internal stresses in externally loaded 2D dislocation systems
Creators: name: Ispánovity, Péter Dusán
name: Groma, István
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The distribution of internal shear stresses in a 2D dislocation system is investigated when external shear stress is applied. This problem serves as a natural continuation of the previous work of Csikor and Groma (Csikor F F and Groma I 2004 Phys. Rev. B 58 2969), where analytical result was given for the stress distribution function at zero applied stress. First, the internal stress distribution generated by a set of randomly positioned ideal dislocation dipoles is studied. Analytical calculations are carried out for this case. The theoretical predictions are checked by numerical simulations showing perfect agreement. It is found that for real relaxed dislocation configurations the role of dislocation multipoles cannot be neglected, but the theory presented can still be applied.
description: 27 pages, 20 figures
An HI absorbing circumnuclear disk in Cygnus A
Creators: name: Struve, Christian
name: Conway, John E.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present Very Long Baseline Array (VLBA) HI absorption observations of the core region of the powerful radio galaxy Cygnus A. These data show both broad (FWHM = 231 \pm 21 km/s) and narrow (FWHM <30 km/s) velocity width absorption components. The broad velocity absorption shows high opacity on the counter jet, low opacity against the core and no absorption on the jet side. We argue that these results are most naturally explained by a circumnuclear HI absorbing disk orientated roughly perpendicular to the jet axis. We estimate that the HI absorbing gas lies at a radius of ~80 pc has a scale height of about 20 pc, density n > 10^{4} cm^{-3} and total column density in the range 10^{23}-10^{24} cm^{-2}. Models in which the HI absorption is primarily from an atomic or a molecular gas phase can both fit our data. Modelling taking into account the effective beam shows that the broad HI absorbing gas component does not cover the radio core in Cygnus A and therefore does not contribute to the gas column that blocks our view of the hidden quasar nucleus. If however Cygnus A were observed from a different direction, disk gas on ~100 pc radius scales would contribute significantly to the nuclear column density, implying that in some radio galaxies gas on these scales may contribute to the obscuration of the central engine. We argue that the circumnuclear torus in Cygnus A contains too little mass to power the AGN over > 10^{7} yr but that material in the outer HI absorbing gas disk can provide a reservoir to fuel the AGN and replenish torus clouds. The second narrow HI absorption component is significantly redshifted (by 186km/s) with respect to the systemic velocity and probably traces infalling gas which will ultimately fuel the source. [abridged]
description: 9 pages, 4 figures; A&A, in press
The stochastic X-ray variability of the accreting millisecond pulsar IGR J17062-6143
Creators: name: Bult, Peter
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: This work presents an investigation of the stochastic X-ray variability from the 164 Hz accreting millisecond pulsar IGR J17062-6143, based on regular observations collected with the Neutron Star Interior Composition Explorer between 2017 July and 2020 August. Over this period, the power density spectrum showed a stable morphology, with broad $\sim25\%$ rms band-limited noise below 16 Hz. Quasi-periodic oscillations (QPOs) were occasionally observed, with the most notably detections including a low-frequency QPO centered at 2.7 Hz and a sharp QPO centered at 115 Hz that may be a 2:3 resonance with the spin frequency. Further, the energy dependence of the band-limited noise is studied through a spectroscopic analysis of the complex covariance in two frequency intervals. It is found that the power law continuum is the primary driver for the observed variability, although the thermal (blackbody) emission also appears to be intrinsically variable in area ($5\%$ rms) and temperature ($1\%$ rms). Notably, the 1 keV emission feature seen in all X-ray spectra of IGR J17062-6143 varies with the same amplitude as the power law, but systematically lags behind that continuum emission. These results appear consistent with a scenario in which a time variable Compton-scattering corona is the primary source for the observed stochastic variability, with the variability observed in the emission feature and at the lowest photon energies being due to the disk reflection of the power law continuum.
description: 13 pages, 5 figures, 3 tables. Accepted for publication in ApJ
FAIRsharing.org – mapping the landscape of databases, standards and policies (describing, linking and assessing their FAIRness)
Creators: name: McQuilton, Peter
Publisher: name: F1000 Research Limited
Year: 2019

description: This short set of slides was presented at the 12th International Society of Biocuration conference in Cambridge April 2019. In these slides, we discuss the FAIRsharing project and our quest to map the landscape of repositories, knowledgebases, data standards (ontologies, reporting guidelines, models/formats, identifier schema and metrics), and data policies from funders and journal publishers. We also touch on how FAIRsharing can help Biocurators identify which standards to use in their work and to understand the landscape of curation around them. This presentation was part of a half-day workshop run by the ELIXIR Biocuration Implementation Study, co-led by ELIXIR UK (Peter McQuilton, FAIRsharing), ELIXIR EMBL-EBI (Sarah Morgan, Melissa Burke, Alexandra Holinski) and ELIXIR-CH (Patricia Pelagi, SIB).
Energy determination of cosmic ray showers in surface arrays using signal inference at a single distance from the core
Creators: name: Ros, G.
name: Medina-Tanco, G.
name: del Peral, L.
name: D'Olivo, J. C.
name: Arqueros, F.
name: Rodriguez-Frias, M. D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In most high energy cosmic ray surface arrays, the primary energy is currently determined from the value of the lateral distribution function at a fixed distance from the shower core, r0. The value of r0 is mainly related to the geometry of the array and is, therefore, considered as fixed independently of the shower energy or direction. We argue, however, that the dependence of r0 on energy and zenith angle is not negligible. Therefore, in the present work we propose a new characteristic distance, which we call ropt, specifically determined for each individual shower, with the objective of optimizing the energy reconstruction. This parameter may not only improve the energy determination, but also allow a more reliable reconstruction of the shape and position of rapidly varying spectral features. We show that the use of a specific ropt determined on a shower-to-shower basis, instead of using a fixed characteristic value, is of particular benefit in dealing with the energy reconstruction of events with saturated detectors, which are in general a large fraction of all the events detected by an array as energy increases. Furthermore, the ropt approach has the additional advantage of applying the same unified treatment for all detected events, regardless of whether they have saturated detectors or not.
description: 21 pages, 9 figures. Accepted in NIM A
Deep learning for the modeling and inverse design of radiative heat transfer
Creators: name: García-Esteban, Juan José
name: Bravo-Abad, Jorge
name: Cuevas, Juan Carlos
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Deep learning is having a tremendous impact in many areas of computer science and engineering. Motivated by this success, deep neural networks are attracting an increasing attention in many other disciplines, including physical sciences. In this work, we show that artificial neural networks can be successfully used in the theoretical modeling and analysis of a variety of radiative heat transfer phenomena and devices. By using a set of custom-designed numerical methods able to efficiently generate the required training datasets, we demonstrate this approach in the context of three very different problems, namely, (i) near-field radiative heat transfer between multilayer systems that form hyperbolic metamaterials, (ii) passive radiate cooling in photonic-crystal slab structures, and (iii) thermal emission of subwavelength objects. Despite their fundamental differences in nature, in all three cases we show that simple neural network architectures trained with datasets of moderate size can be used as fast and accurate surrogates for doing numerical simulations, as well as engines for solving inverse design and optimization in the context of radiative heat transfer. Overall, our work shows that deep learning and artificial neural networks provide a valuable and versatile toolkit for advancing the field of thermal radiation.
description: 16 pages, 11 figures
Accretion and plasma outflow from dissipationless discs
Creators: name: Bogovalov, Sergei
name: Kelner, Stanislav
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We consider an extreme case of disc accretion onto a gravitating centre when the viscosity in the disc is negligible. The angular momentum and the rotational energy of the accreted matter is carried out by a magnetized wind outflowing from the disc. The outflow of matter from the disc occurs due to the Blandford & Payne(1982) centrifugal mechanism. The disc is assumed to be cold. Accretion and outflow are connected by the conservation of the energy, mass and the angular momentum. The basic properties of the outflow, angular momentum flux and energy flux per particle in the wind, do not depend on the details of the structure of the accretion disc. In the case of selfsimilar accretion/outflow, the dependence of the rate of accretion $\dot M$ in the disc depends on the disc radius $r$ on the law $\dot M \sim r^{1\over2(α^2-1)}$, where $α$ is a dimensionless Alfvenic radius. In the case of $α\gg 1$, the accretion in the disc is provided by very weak matter outflow from the disc and the outflow predominantly occurs from the very central part of the disc. The solution obtained in the work provides mechanism which transforms the gravitational energy of the accreted matter into the energy of the outflowing wind with efficiency close to 100%. The final velocity can essentially exceed Kepler velocity at the site of the wind launch. This mechanism allows us to understand the nature of the astrophysical objects with low luminosity discs and energetic jet-like outflows.
description: Submitted to MNRAS