cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Weakly collisional Landau damping and three-dimensional Bernstein-Greene-Kruskal modes: New results on old problems
Creators: name: Ng, C. S.
name: Bhattacharjee, A.
name: Skiff, F.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Space Physics (physics.space-ph)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Landau damping and Bernstein-Greene-Kruskal (BGK) modes are among the most fundamental concepts in plasma physics. While the former describes the surprising damping of linear plasma waves in a collisionless plasma, the latter describes exact undamped nonlinear solutions of the Vlasov equation. There does exist a relationship between the two: Landau damping can be described as the phase-mixing of undamped eigenmodes, the so-called Case-Van Kampen modes, which can be viewed as BGK modes in the linear limit. While these concepts have been around for a long time, unexpected new results are still being discovered. For Landau damping, we show that the textbook picture of phase-mixing is altered profoundly in the presence of collision. In particular, the continuous spectrum of Case-Van Kampen modes is eliminated and replaced by a discrete spectrum, even in the limit of zero collision. Furthermore, we show that these discrete eigenmodes form a complete set of solutions. Landau-damped solutions are then recovered as true eigenmodes (which they are not in the collisionless theory). For BGK modes, our interest is motivated by recent discoveries of electrostatic solitary waves in magnetospheric plasmas. While one-dimensional BGK theory is quite mature, there appear to be no exact three-dimensional solutions in the literature (except for the limiting case when the magnetic field is sufficiently strong so that one can apply the guiding-center approximation). We show, in fact, that two- and three-dimensional solutions that depend only on energy do not exist. However, if solutions depend on both energy and angular momentum, we can construct exact three-dimensional solutions for the unmagnetized case, and two-dimensional solutions for the case with a finite magnetic field. The latter are shown to be exact, fully electromagnetic solutions of the steady-state Vlasov-Poisson-Ampère system.
Appendix II: Terra Petraea Point Pattern Analysis R-script
Creators: name: Kennedy, Will M.
Publisher: name: Zenodo
Year: 2021
Subjects: Terra Petraea

description: This second appendix to "Terra Petraea. The Archaeological Landscape of the Petraean Hinterland from the Hellenistic to the Byzantine Period" (ISBN 978-3-8325-5171-1) is a PDF version of the R-script written by the author for conducting the point pattern analyses (cf. chapter 2).
Uncertainty quantification for fault slip inversion
Creators: name: Montesinos-López, J. Cricelio
name: Capella, Antonio
name: Christen, J. Andrés
name: Tago, Josué
Publisher: name: arXiv
Year: 2020
Subjects: subject: Methodology (stat.ME)
subject: Geophysics (physics.geo-ph)
subject: Computation (stat.CO)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: 86-10

description: We propose an efficient Bayesian approach to infer a fault displacement from geodetic data in a slow slip event. Our physical model of the slip process reduces to a multiple linear regression subject to constraints. Assuming a Gaussian model for the geodetic data and considering a multivariate truncated normal prior distribution for the unknown fault slip, the resulting posterior distribution is also multivariate truncated normal. Regarding the posterior, we propose an algorithm based on Optimal Directional Gibbs that allows us to efficiently sample from the resulting high-dimensional posterior distribution of along dip and along strike movements of our fault grid division. A synthetic fault slip example illustrates the flexibility and accuracy of the proposed approach. The methodology is also applied to a real data set, for the 2006 Guerrero, Mexico, Slow Slip Event, where the objective is to recover the fault slip on a known interface that produces displacements observed at ground geodetic stations. As a by-product of our approach, we are able to estimate moment magnitude for the 2006 Guerrero Event with uncertainty quantification.
description: 27 pages, 12 figures
Maximum-likelihood parameter estimation in terahertz time-domain spectroscopy
Creators: name: Mohtashemi, Laleh
name: Westlund, Paul
name: Sahota, Derek G.
name: Lea, Graham B.
name: Bushfield, Ian
name: Mousavi, Payam
name: Dodge, J. Steven
Publisher: name: arXiv
Year: 2020
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We present a maximum-likelihood method for parameter estimation in terahertz time-domain spectroscopy. We derive the likelihood function for a parameterized frequency response function, given a pair of time-domain waveforms with known time-dependent noise amplitudes. The method provides parameter estimates that are superior to other commonly-used methods, and provides a reliable measure of the goodness of fit. We also develop a simple noise model that is parameterized by three dominant sources, and derive the likelihood function for their amplitudes in terms of a set of repeated waveform measurements. We demonstrate the method with applications to material characterization.
description: 15 pages, 6 figures; minor formatting updates
TriSol: a major upgrade of the TwinSol RNB facility
Creators: name: O'Malley, P. D.
name: Ahn, T.
name: Bardayan, D. W.
name: Brodeur, M.
name: Coil, S.
name: Kolata, J. J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We report here on the recent upgrade of the TwinSol radioactive nuclear beam (RNB) facility at the University of Notre Dame. The new TriSol system includes a magnetic dipole to provide a second beamline and a third solenoid which acts to reduce the size of the radioactive beam on target.
description: submitted to Nuclear Instruments and Methods A
Extending torsors over regular models of curves
Creators: name: Mehidi, Sara
Publisher: name: arXiv
Year: 2020
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: Let $R$ be a discrete valuation ring with field of fractions $K$ and residue field $k$ of characteristic $p>0$. Given a finite commutative group scheme $G$ over $K$ and a smooth projective curve $C$ over $K$ with a rational point, we study the extension of pointed fppf $G$-torsors over $C$ to pointed torsors over some $R$-regular model $\mathcal{C}$ of $C$. We first study this problem in the category of log schemes: given a finite flat $R$-group scheme $\mathcal{G}$, we prove that the data of a pointed $\mathcal{G}$-log torsor over $\mathcal{C}$ is equivalent to that of a morphism $\mathcal{G}^D \to \mathrm{Pic}^{log}_{\mathcal{C}/R}$, where $\mathcal{G}^D$ is the Cartier dual of $\mathcal{G}$ and $\mathrm{Pic}^{log}_{\mathcal{C}/R}$ the log Picard functor. Then, we deduce a criterion for the extension of torsors: it suffices to find a finite flat model of $G$ over $R$ for which a certain group scheme morphism to the Jacobian $J$ of $C$ extends to the Néron model of $J$. In this context, we compute the obstruction for the extended log torsor to come from an fppf one. In a second part, we generalize a result of Chiodo which gives a criterion for the $r$-torsion subgroup of the Néron model of $J$ to be a finite flat group scheme, and we combine it with the results of the first part. Finally, we give two detailed examples of extension of torsors when $C$ is a hyperelliptic curve defined over $\mathbb{Q}$, which will illustrates our techniques.
Ausstellungskataloge und Museumsberichte
Creators: name: Redaktion, Die
Publisher: name: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Year: 2020

description: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege, Bd. 21 Nr. 10 (1968): Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
A quantization procedure based on completely positive maps and Markov operators
Creators: name: Lardizabal, Carlos F.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We describe $ω$-limit sets of completely positive (CP) maps over finite-dimensional spaces. In such sets and in its corresponding convex hulls, CP maps present isometric behavior and the states contained in it commute with each other. Motivated by these facts, we describe a quantization procedure based on CP maps which are induced by Markov (transfer) operators. Classical dynamics are described by an action over essentially bounded functions. A non-expansive linear map, which depends on a choice of a probability measure, is the centerpiece connecting phenomena over function and matrix spaces.
Establishing the accuracy of asteroseismic mass and radius estimates of giant stars III. KIC4054905, an eclipsing binary with two 10 Gyr thick disk RGB stars
Creators: name: Brogaard, K.
name: Arentoft, T.
name: Slumstrup, D.
name: Grundahl, F.
name: Lund, M. N.
name: Arndt, L.
name: Grund, S.
name: Rudrasingam, J.
name: Theil, A.
name: Christensen, K.
name: Sejersen, M.
name: Vorgod, F.
name: Salmonsen, L.
name: Endelt, L. Ørtoft
name: Dainese, S.
name: Frandsen, S.
name: Miglio, A.
name: Tayar, J.
name: Huber, D.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Eclipsing binary stars with an oscillating giant component allow accurate stellar parameters to be derived and asteroseismic methods to be tested and calibrated. To this aim, suitable systems need to be firstly identified and secondly measured precisely and accurately. KIC 4054905 is one such system, which has been identified, but with measurements of a relatively low precision and with some confusion regarding its parameters and evolutionary state. Our aim is to provide a detailed and precise characterisation of the system and to test asteroseismic scaling relations. Dynamical and asteroseismic parameters of KIC4054905 were determined from Kepler photometry and multi-epoch high-resolution spectra from FIES at the Nordic Optical Telescope. KIC 4054905 was found to belong to the thick disk and consist of two lower red giant branch (RGB) components with nearly identical masses of 0.95$M_{\odot}$ and an age of $9.9\pm0.6$ Gyr. The most evolved star displays solar-like oscillations, which suggest that the star belongs to the RGB, supported also by the radius, which is significantly smaller than the red clump phase for this mass and metallicity. Masses and radii from corrected asteroseismic scaling relations can be brought into full agreement with the dynamical values if the RGB phase is assumed, but a best scaling method could not be identified. We measured dynamical masses and radii with a precision better than 1.0%. We firmly establish the evolutionary nature of the system to be that of two early RGB stars with an age close to 10 Gyr, unlike previous findings. The metallicity and Galactic velocity suggest that the system belongs to the thick disk of the Milky Way. We investigate the agreement between dynamical and asteroseismic parameters for KIC 4054905. Consistent solutions exist, but the need to analyse more systems continues in order to establish the accuracy of asteroseismic methods.
description: Accepted for publication in Astronomy & Astrophysics, 11 pages, 3 figures
Inhalt
Creators: name: Redaktion, Die
Publisher: name: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Year: 2020

description: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege, Bd. 21 Nr. 11 (1968): Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Marienbild in Rheinland und Westfalen
Creators: name: Pieper, Paul
Publisher: name: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Year: 2020

description: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege, Bd. 21 Nr. 11 (1968): Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
The effective Hamiltonian in curved quantum waveguides under mild regularity assumptions
Creators: name: Krejcirik, David
name: Sedivakova, Helena
Publisher: name: arXiv
Year: 2012
Subjects: subject: Spectral Theory (math.SP)
subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: The Dirichlet Laplacian in a curved three-dimensional tube built along a spatial (bounded or unbounded) curve is investigated in the limit when the uniform cross-section of the tube diminishes. Both deformations due to bending and twisting of the tube are considered. We show that the Laplacian converges in a norm-resolvent sense to the well known one-dimensional Schroedinger operator whose potential is expressed in terms of the curvature of the reference curve, the twisting angle and a constant measuring the asymmetry of the cross-section. Contrary to previous results, we allow the reference curves to have non-continuous and possibly vanishing curvature. For such curves, the distinguished Frenet frame standardly used to define the tube need not exist and, moreover, the known approaches to prove the result for unbounded tubes do not work. Our main ideas how to establish the norm-resolvent convergence under the minimal regularity assumptions are to use an alternative frame defined by a parallel transport along the curve and a refined smoothing of the curvature via the Steklov approximation.
description: 29 pages, 6 figures
Scattering variability detected from the circumsource medium of FRB 20190520B
Creators: name: Ocker, S. K.
name: Cordes, J. M.
name: Chatterjee, S.
name: Li, D.
name: Niu, C. H.
name: McKee, J. W.
name: Law, C. J.
name: Anna-Thomas, R.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Fast radio bursts (FRBs) are millisecond-timescale radio transients, the origins of which are predominantly extragalactic and likely involve highly magnetized compact objects. FRBs undergo multipath propagation, or scattering, from electron density fluctuations on sub-parsec scales in ionized gas along the line-of-sight. Scattering observations have located plasma structures within FRB host galaxies, probed Galactic and extragalactic turbulence, and constrained FRB redshifts. Scattering also inhibits FRB detection and biases the observed FRB population. We report the detection of scattering times from the repeating FRB 20190520B that vary by up to a factor of two or more on minutes to days-long timescales. In one notable case, the scattering time varied from $7.9\pm0.4$ ms to less than 3.1 ms ($95\%$ confidence) over 2.9 minutes at 1.45 GHz. The scattering times appear to be uncorrelated between bursts or with dispersion and rotation measure variations. Scattering variations are attributable to dynamic, inhomogeneous plasma in the circumsource medium, and analogous variations have been observed from the Crab pulsar. Under such circumstances, the frequency dependence of scattering can deviate from the typical power-law used to measure scattering. Similar variations may therefore be detectable from other FRBs, even those with inconspicuous scattering, providing a unique probe of small-scale processes within FRB environments.
description: 10 pages, 9 figures, accepted to MNRAS
Nonequilibrium Green's function theory of coherent excitonic effects in the photocurrent response of semiconductor nanostructures
Creators: name: Aeberhard, U.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Excitonic contributions to absorption and photocurrent generation in semiconductor nanostructures are described theoretically and simulated numerically using steady-state non-equilibrium Green's function theory. In a first approach, the coherent interband polarization including Coulomb corrections is determined from a Bethe-Salpeter-type equation for the equal time interband single-particle charge carrier Green's function. The effects of excitonic absorption on photocurrent generation are considered on the same level of approximation via the derivation of the corresponding corrections to the electron-photon self-energy.
description: 8 pages, 4 figures
Mitgliederversammlung des Deutschen Vereins für Kunstwissenschaft am 11. Oktober 1968 in Ulm
Creators: name: Redaktion, Die
Publisher: name: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Year: 2020

description: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege, Bd. 21 Nr. 12 (1968): Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Enhanced Soft Limits in de Sitter Space
Creators: name: Armstrong, Connor
name: Lipstein, Arthur
name: Mei, Jiajie
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In flat space, the scattering amplitudes of certain scalar effective field theories exhibit enhanced soft limits due to the presence of hidden symmetries. In this paper, we show that this phenomenon extends to wavefunction coefficients in de Sitter space. Using a representation in terms of boundary conformal generators acting on contact diagrams, we find that imposing enhanced soft limits fixes the masses and four-point couplings (including curvature corrections) in agreement with Lagrangians recently derived from hidden symmetries. Higher-point couplings can then be fixed using a bootstrap procedure which we illustrate at six points. We also discuss implications for the double copy in de Sitter space.
description: v2. published in JHEP
Charged Particle Tracking in Real-Time Using a Full-Mesh Data Delivery Architecture and Associative Memory Techniques
Creators: name: Ajuha, Sudha
name: Shinoda, Ailton Akira
name: Ramalho, Lucas Arruda
name: Baulieu, Guillaume
name: Boudoul, Gaelle
name: Casarsa, Massimo
name: Cascadan, Andre
name: Clement, Emyr
name: de Paiva, Thiago Costa
name: Das, Souvik
name: Dutta, Suchandra
name: Eusebi, Ricardo
name: Fedi, Giacomo
name: Ferreira, Vitor Finotti
name: Hahn, Kristian
name: Hu, Zhen
name: Jindariani, Sergo
name: Konigsberg, Jacobo
name: Liu, Tiehui
name: Low, Jia Fu
name: MacDonald, Emily
name: Olsen, Jamieson
name: Palla, Fabrizio
name: Pozzobon, Nicola
name: Rathjens, Denis
name: Ristori, Luciano
name: Rossin, Roberto
name: Sung, Kevin
name: Tran, Nhan
name: Trovato, Marco
name: Ulmer, Keith
name: Vaz, Mario
name: Viret, Sebastien
name: Wu, Jin-Yuan
name: Xu, Zijun
name: Zorzetti, Silvia
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We present a flexible and scalable approach to address the challenges of charged particle track reconstruction in real-time event filters (Level-1 triggers) in collider physics experiments. The method described here is based on a full-mesh architecture for data distribution and relies on the Associative Memory approach to implement a pattern recognition algorithm that quickly identifies and organizes hits associated to trajectories of particles originating from particle collisions. We describe a successful implementation of a demonstration system composed of several innovative hardware and algorithmic elements. The implementation of a full-size system relies on the assumption that an Associative Memory device with the sufficient pattern density becomes available in the future, either through a dedicated ASIC or a modern FPGA. We demonstrate excellent performance in terms of track reconstruction efficiency, purity, momentum resolution, and processing time measured with data from a simulated LHC-like tracking detector.
The emergence of Noncommutative Potential Theory
Creators: name: Cipriani, Fabio E. G.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Operator Algebras (math.OA)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 46L89(31C25 46L10 60J45 81R15)

description: We review origins and developments of Noncommutative Potential theory as underpinned by the notion of energy form. Recent and new applications are shown to approximation properties of von Neumann algebras.
Unintegrated gluon distributions from the color dipole cross section in the BGK saturation model
Creators: name: Łuszczak, Agnieszka
name: Łuszczak, Marta
name: Schäfer, Wolfgang
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We evaluate the unintegrated gluon distribution of the proton starting from a parametrization of the color dipole cross section including DGLAP evolution and saturation effects. To this end, we perform the Fourier-Bessel transform of $σ(x,r)/α(r)$. At large transverse momentum of gluons we match the so-obtained distribution to the logarithmic derivative of the collinear gluon distribution. We check our approach by calculating the proton structure function $F_L(x,Q^2)$ finding good agreement with HERA data.
description: 4 pages, 3 figs
Mechanism for puddle formation in graphene
Creators: name: Adam, Shaffique
name: Jung, Suyong
name: Klimov, Nikolai N.
name: Zhitenev, Nikolai B.
name: Stroscio, Joseph A.
name: Stiles, M. D.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: When graphene is close to charge neutrality, its energy landscape is highly inhomogeneous, forming a sea of electron-like and hole-like puddles, which determine the properties of graphene at low carrier density. However, the details of the puddle formation have remained elusive. We demonstrate numerically that in sharp contrast to monolayer graphene, the normalized autocorrelation function for the puddle landscape in bilayer graphene depends only on the distance between the graphene and the source of the long-ranged impurity potential. By comparing with available experimental data, we find quantitative evidence for the implied differences in scanning tunneling microscopy measurements of electron and hole puddles for monolayer and bilayer graphene in nominally the same disorder potential.
description: 7 pages, 6 figures
Campus Activism in the White South: An Examination of the Southern Student Organizing Committee
Creators: name: Storch, Adam
Publisher: name: University of Chicago
Year: 2023
Subjects: subject: SSOC
subject: New Left
subject: Activism
subject: Regionalism
subject: Microhistory
subject: Race

description: The work of students was instrumental to the “New Left” movements of the 1960s in the United States. This paper examines one nearly forgotten group of student activists from the period, the Southern Student Organizing Committee (SSOC). The SSOC, active from 1964 to 1969, was a group of mostly white students working to bring white students into the progressive movements of the period such as the black freedom struggle, the antiwar movement, and campus free speech movements. This paper explores the impact of this student group, focusing on their commitment to southern regionalism in their outreach and organizing, as well as how these activists confronted the hostility that came with organizing in a largely conservative environment. Their work was essential for introducing these movements to campuses and communities that would have otherwise never engaged with the New Left. The group’s struggles engage with their peers and enter communities combined with internal organizational fissures to bring about the dissolution of the SSOC in 1969. The examination of the SSOC from their founding to their downfall demonstrates that the challenges faced by white organizers in the South were indeed unique to the South, and it helps to further our understanding of student activism in the South during the 1960s and how regionalism can be implemented into activist strategies.
First Detection of Near-Infrared Line Emission from Organics in Young Circumstellar Disks
Creators: name: Mandell, A. M.
name: Bast, J.
name: van Dishoeck, E. F.
name: Blake, G. A.
name: Salyk, C.
name: Mumma, M. J.
name: Villanueva, G.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present an analysis of high-resolution spectroscopy of several bright T Tauri stars using the VLT/CRIRES and Keck/NIRSPEC spectrographs, revealing the first detections of emission from HCN and C2H2 in circumstellar disks at near-infrared wavelengths. Using advanced data reduction techniques we achieve a dynamic range with respect to the disk continuum of ~500 at 3 microns, revealing multiple emission features of H2O, OH, HCN, and C2H2. We also present stringent upper limits for two other molecules thought to be abundant in the inner disk, CH4 and NH3. Line profiles for the different detected molecules are broad but centrally peaked in most cases, even for disks with previously determined inclinations of greater than 20 degrees, suggesting that the emission has both a Keplerian and non-Keplerian component as observed previously for CO emission. We apply two different modeling strategies to constrain the molecular abundances and temperatures: we use a simplified single-temperature LTE slab model with a Gaussian line profile to make line identifications and determine a best-fit temperature and initial abundance ratios, and we compare these values with constraints derived from a detailed disk radiative transfer model assuming LTE excitation but utilizing a realistic temperature and density structure. Abundance ratios from both sets of models are consistent with each other and consistent with expected values from theoretical chemical models, and analysis of the line shapes suggests the molecular emission originates from within a narrow region in the inner disk (R < 1 AU).
description: Accepted to the Astrophysical Journal
Redaktionelle Mitteilung
Creators: name: Redaktion, Die
Publisher: name: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Year: 2020

description: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege, Bd. 21 Nr. 12 (1968): Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Ekhart Berckenhagen, Anton Graff, Leben und Werk
Creators: name: Brand, Erna
Publisher: name: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Year: 2020

description: Rezension zu: Ekhart Berckenhagen, Anton Graff, Leben und Werk. Berlin. (Deutscher Verein für Kunstwissenschaft) 1967. 440 S. mit 650 Abb. im Text. DM 160. - .
description: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege, Bd. 21 Nr. 9 (1968): Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Trajectory Design for the ESA LISA Mission
Creators: name: Martens, Waldemar
name: Joffre, Eric
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The three Laser Interferometer Space Antenna (LISA) spacecraft are going to be placed in a triangular formation in an Earth-trailing or Earth-leading orbit. They will be launched together on a single rocket and transferred to that science orbit using Solar Electric Propulsion. Since the transfer $Δv$ depends on the chosen science orbit, both transfer and science orbit have been optimised together. For a thrust level of 90 mN, an allocation of 1092 m/s per spacecraft is sufficient for an all-year launch in 2034. For every launch month a dedicated science orbit is designed with a corner angle variation of close to $60^\circ \pm 1.0^\circ$ and an arm length rate of maximum 10 m/s. Moreover, a detailed navigation analysis of the science orbit insertion and the impact on insertion errors on the constellation stability has been conducted. The analysis shows that Range/Doppler measurements together with a series of correction manoeuvres at the beginning of the science orbit phase can reduce insertion dispersions to a level where corner angle variations remain at about $60^\circ \pm 1.1^\circ$ at $99\%$ C.L.. However, the situation can become significantly worse if the self-gravity accelerations acting during the science orbit phase are not sufficiently characterised prior to science orbit insertion.
Non-Archimedean Quantum Mechanics via Quantum Groups
Creators: name: Zúñiga-Galindo, W. A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: Primary: 81Q35, 81Q65. Secondary: 26E30, 81R50, 81S05

description: We present a new non-Archimedean realization of the Fock representation of the q-oscillator algebras where the creation and annihilation operators act on complex-valued functions, which are defined on a non-Archimedean local field of arbitrary characteristic, for instance, the field of p-adic numbers. This new realization implies that a large number of quantum models constructed using q-oscillator algebras are non-Archimedean models, in particular, p-adic quantum models. In this framework, we select a q-deformation of the Heisenberg uncertainty relation, and construct the corresponding q-deformed Schrödinger equations. In this way we construct a p-adic quantum mechanics which is a p-deformed quantum mechanics. We also solve the time-independent Schrödinger equations for the free particle, and a particle in a non-Archimedean box. In the last case we show the existence of a discrete sequence of energy levels. We determine the eigenvalues of Schrödinger operator for a general radial potential. By choosing the potential in a suitable form we recover the energy levels of the q-hydrogen atom.
description: Final version. To appear in Nuclear Physics B
All-optical beam steering using the polariton lighthouse effect
Creators: name: Luk, Samuel M. H.
name: Vergnet, Hadrien
name: Lafont, Ombline
name: Lewandowski, Przemyslaw
name: Kwong, Nai H.
name: Galopin, Elisabeth
name: Lemaitre, Aristide
name: Roussignol, Philippe
name: Tignon, Jérôme
name: Schumacher, Stefan
name: Binder, Rolf
name: Baudin, Emmanuel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: We demonstrate theoretically and experimentally that a specifically designed microcavity driven in the optical parametric oscillation regime exhibits lighthouse-like emission, i.e., an emission focused around a single direction. Remarkably, the emission direction of this micro-lighthouse is continuously controlled by the linear polarization of the incident laser, and angular beam steering over \unit{360}{\degree} is demonstrated. Theoretically, this unprecedented effect arises from the interplay between the nonlinear optical response of microcavity exciton-polaritons, the difference in the subcavities forming the microcavity, and the rotational invariance of the device.
description: 16 pages, 4 figures, preprint version
Zuschrift an die Redaktion
Creators: name: Redaktion, Die
Publisher: name: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Year: 2020

description: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege, Bd. 21 Nr. 9 (1968): Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Alfred Neumeyer †
Creators: name: Heise, Carl Georg
Publisher: name: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
Year: 2020

description: Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege, Bd. 26 Nr. 5 (1973): Kunstchronik. Monatsschrift für Kunstwissenschaft, Museumswesen und Denkmalpflege
The metallicity's fundamental dependence on both local and global galactic quantities
Creators: name: Baker, William M.
name: Maiolino, Roberto
name: Belfiore, Francesco
name: Curti, Mirko
name: Bluck, Asa F. L.
name: Lin, Lihwai
name: Ellison, Sara L.
name: Thorp, Mallory
name: Pan, Hsi-An
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study the scaling relations between gas-phase metallicity, stellar mass surface density ($Σ_*$), star formation rate surface density ($Σ_{SFR}$), and molecular gas surface density ($Σ_{H_2}$) in local star-forming galaxies on scales of a kpc. We employ optical integral field spectroscopy from the MaNGA survey, and ALMA data for a subset of MaNGA galaxies. We use Partial Correlation Coefficients and Random Forest regression to determine the relative importance of local and global galactic properties in setting the gas-phase metallicity. We find that the local metallicity depends primarily on $Σ_*$ (the resolved mass-metallicity relation, rMZR), and has a secondary anti-correlation with $Σ_{SFR}$ (i.e. a spatially-resolved version of the 'Fundamental Metallicity Relation', rFMR). We find that $Σ_{H_2}$ is less important than $Σ_{SFR}$ in determining the local metallicity. This result indicates that gas accretion, resulting in local metallicity dilution and local boosting of star formation, is unlikely to be the primary origin of the rFMR. The local metallicity depends also on the global properties of galaxies. We find a strong dependence on the total stellar mass ($M_*$) and a weaker (inverse) dependence on the total SFR. The global metallicity scaling relations, therefore, do not simply stem out of their resolved counterparts; global properties and processes, such as the global gravitational potential well, galaxy-scale winds and global redistribution/mixing of metals, likely contribute to the local metallicity, in addition to local production and retention.
description: 22 pages, 24 figures, Accepted for publication in MNRAS
Discovery of the millisecond pulsar PSR J2043+1711 in a Fermi source with the Nancay Radio Telescope
Creators: name: Guillemot, L.
name: Freire, P. C. C.
name: Cognard, I.
name: Johnson, T. J.
name: Takahashi, Y.
name: Kataoka, J.
name: Desvignes, G.
name: Camilo, F.
name: Ferrara, E. C.
name: Harding, A. K.
name: Janssen, G. H.
name: Keith, M.
name: Kerr, M.
name: Kramer, M.
name: Parent, D.
name: Ransom, S. M.
name: Ray, P. S.
name: Parkinson, P. M. Saz
name: Smith, D. A.
name: Stappers, B. W.
name: Theureau, G.
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We report the discovery of the millisecond pulsar PSR J2043+1711 in a search of a Fermi Large Area Telescope (LAT) source with no known associations, with the Nancay Radio Telescope. The new pulsar, confirmed with the Green Bank Telescope, has a spin period of 2.38 ms, is relatively nearby (d
description: 14 pages, 6 figures, 3 tables, accepted for publication in MNRAS
Performance of the low-rank tensor-train SVD (TT-SVD) for large dense tensors on modern multi-core CPUs
Creators: name: Röhrig-Zöllner, Melven
name: Thies, Jonas
name: Basermann, Achim
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: Mathematical Software (cs.MS)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: G.4; G.1.3
subject: 15A23, 15A69, 65F99, 65Y05, 65Y20

description: There are several factorizations of multi-dimensional tensors into lower-dimensional components, known as `tensor networks'. We consider the popular `tensor-train' (TT) format and ask: How efficiently can we compute a low-rank approximation from a full tensor on current multi-core CPUs? Compared to sparse and dense linear algebra, kernel libraries for multi-linear algebra are rare and typically not as well optimized. Linear algebra libraries like BLAS and LAPACK may provide the required operations in principle, but often at the cost of additional data movements for rearranging memory layouts. Furthermore, these libraries are typically optimized for the compute-bound case (e.g.\ square matrix operations) whereas low-rank tensor decompositions lead to memory bandwidth limited operations. We propose a `tensor-train singular value decomposition' (TT-SVD) algorithm based on two building blocks: a `Q-less tall-skinny QR' factorization, and a fused tall-skinny matrix-matrix multiplication and reshape operation. We analyze the performance of the resulting TT-SVD algorithm using the Roofline performance model. In addition, we present performance results for different algorithmic variants for shared-memory as well as distributed-memory architectures. Our experiments show that commonly used TT-SVD implementations suffer severe performance penalties. We conclude that a dedicated library for tensor factorization kernels would benefit the community: Computing a low-rank approximation can be as cheap as reading the data twice from main memory. As a consequence, an implementation that achieves realistic performance will move the limit at which one has to resort to randomized methods that only process part of the data.
description: 26 pages, 16 figures, accepted by SISC
Theory of Optical Activity in Doped Systems with Application to Twisted Bilayer Graphene
Creators: name: Chang, K.
name: Zheng, Z.
name: Sipe, J. E.
name: Cheng, J. L.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We theoretically study the optical activity in a doped system and derive the optical activity tensor from a light wavevector-dependent linear optical conductivity. Although the light-matter interaction is introduced through the velocity gauge from a minimal coupling Hamiltonian, we find that the well-known ``false divergences'' problem can be avoided in practice if the electronic states are described by a finite band effective Hamiltonian, such as a few-band tight-binding model. The expression we obtain for the optical activity tensor is in good numerical agreement with a recent theory derived for an undoped topologically trivial gapped system. We apply our theory to the optical activity of a gated twisted bilayer graphene, with a detailed discussion of the dependence of the results on twist angle, chemical potential, gate voltage, and location of rotation center forming the twisted bilayer graphene.
Evaluation of different recipes for chromospheric radiative losses in solar flares
Creators: name: Tian, J.
name: Hong, J.
name: Li, Y.
name: Ding, M. D.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Context. Radiative losses are an indispensable part in the numerical simulation of flares. Detailed calculations could be computationally expensive, especially in the chromosphere. There have been some approximate recipes for chromospheric radiative losses in flares, yet their feasibility in flare simulations needs further evaluation. Aims. We aim to evaluate the performance of different recipes for chromospheric radiative losses in flare simulations. Methods. We compare the atmospheric structure and line profiles in beam-heated flares calculated with detailed radiative losses and the approximate recipes. Results. Both GF90 and HCD22 recipes provide acceptable total radiative losses compared with detailed one, but there are discrepancies in the different atmospheric layers during the different evolutionary phases, which leads to misestimations of temperature and line intensity. The recipe of GF90 overestimates the coolings in the upper chromosphere greatly when temperature exceeds 10^5 K, which also affects the flare evolution and line asymmetries. Radiative heating in the middle chromosphere only functions in the initial stage and could be safely neglected. However, radiative heating from Lyman continuum could dominate near the transition region.
description: 16 pages, 11 figures, 3 tables. A&A accepted
Staggered moment dependence on field-tuned quantum fluctuations in 2D frustrated antiferromagnets
Creators: name: Siahatgar, Mohammad
name: Schmidt, Burkhard
name: Thalmeier, Peter
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We propose an efficient method to identify the degree of frustration in quasi-2D antiferromagnets described by the J_1-J_2 Heisenberg model. The frustration ratio J_2/J_1 is usually obtained from analysis of susceptibility, specific heat and saturation field. We show that the non-monotonic field dependence of the staggered moment caused by the suppression of quantum fluctuations in a field depends strongly on the frustration ratio. This gives a powerful criterion to determine J_2/J_1 using a combination of exact diagonalization (ED) method for finite clusters and spin wave analysis. We apply this method to the quasi-2D compound Cu(pz)_2(ClO_4)_2 and show that it leads to an intermediate ratio J_2/J_1 ~ 0.2 for the frustration. We also explain the observed anomalous increase of transition temperature in applied fields as an effect of reduced quantum fluctuations.
description: 5 pages, 5 figures, accepted for publication in Phys. Rev. B
An Online Approach to Cyberattack Detection and Localization in Smart Grid
Creators: name: Li, Dan
name: Gebraeel, Nagi
name: Paynabar, Kamran
name: Meliopoulos, A. P. Sakis
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applications (stat.AP)
subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: Complex interconnections between information technology and digital control systems have significantly increased cybersecurity vulnerabilities in smart grids. Cyberattacks involving data integrity can be very disruptive because of their potential to compromise physical control by manipulating measurement data. This is especially true in large and complex electric networks that often rely on traditional intrusion detection systems focused on monitoring network traffic. In this paper, we develop an online detection algorithm to detect and localize covert attacks on smart grids. Using a network system model, we develop a theoretical framework by characterizing a covert attack on a generator bus in the network as sparse features in the state-estimation residuals. We leverage such sparsity via a regularized linear regression method to detect and localize covert attacks based on the regression coefficients. We conduct a comprehensive numerical study on both linear and nonlinear system models to validate our proposed method. The results show that our method outperforms conventional methods in both detection delay and localization accuracy.
Gluon Distribution Functions and Higgs Boson Production at Moderate Transverse Momentum
Creators: name: Sun, Peng
name: Xiao, Bo-Wen
name: Yuan, Feng
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We investigate the gluon distribution functions and their contributions to the Higgs boson production in pp collisions in the transverse momentum dependent factorization formalism. In addition to the usual azimuthal symmetric transverse momentum dependent gluon distribution, we find that the azimuthal correlated gluon distribution also contributes to the Higgs boson production. This explains recent findings on the additional contribution in the transverse momentum resummation for the Higgs boson production as compared to that for electroweak boson production processes. We further examine the small-x naive k_t-factorization in the dilute region and find that the azimuthal correlated gluon distribution contribution is consistently taken into account, and the result agrees with the transverse momentum dependent factorization formalism. We comment on the possible breakdown of the naive k_t-factorization in the dense medium region, due to the unique behaviors for the gluon distributions.
description: 11 pages, no figure
Nándor Kalicz und János Makkay, Die Linienbandkeramik in der großen ungarischen Tiefebene
Creators: name: Lüning, Jens
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Nándor Kalicz und János Makkay, Die Linienbandkeramik in der großen ungarischen Tiefebene. Studia Archaeologica 7. Akadémiai Kiadö, Budapest 1977. 234 Seiten, 47 Abbildungen, 189 Tafeln, 8 Karten.
description: Bonner Jahrbücher, Bd. 182.1982: Bonner Jahrbücher
Turbulence drag modulation by dispersed droplets in Taylor-Couette flow: the effects of the dispersed phase viscosity
Creators: name: Wang, Cheng
name: Yi, Lei
name: Jiang, Linfeng
name: Sun, Chao
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The dispersed phase in turbulence can vary from almost inviscid fluid to highly viscous fluid. By changing the viscosity of the dispersed droplet phase, we experimentally investigate how the deformability of dispersed droplets affects the global transport quantity of the turbulent emulsion. Different kinds of silicone oil are employed to result in the viscosity ratio, $ζ$, ranging from $0.53$ to $8.02$. The droplet volume fraction, $ϕ$, is varied from 0\% to 10\% with a spacing of 2\%. The global transport quantity, quantified by the normalized friction coefficient $c_{f,ϕ}/c_{f,ϕ=0}$, shows a weak dependence on the turbulent intensity due to the vanishing finite-size effect of the droplets. The interesting fact is that, with increasing $ζ$, the $c_{f,ϕ}/c_{f,ϕ=0}$ first increases and then saturates to a plateau value which is similar to that of the rigid particle suspension. By performing image analysis, this drag modification is interpreted from the aspect of droplet deformability, which is responsible for the breakup and coalescence effect of the droplets. The statistics of the droplet size distribution show that, with increasing $ζ$, the stabilizing effect induced by interfacial tension comes to be substantial and the pure inertial breakup process becomes dominant. The measurement of the droplet distribution along the radial direction of the system shows a bulk-clustering effect, which can be attributed to the non-negligible coalescence effect of the droplet. It is found that the droplet coalescence effect could be suppressed as the $ζ$ increases, thereby affecting the contribution of interfacial tension to the total stress, and accounting for the observed emulsion rheology.
description: 17 pages, 8 figures
Squirals and beyond: Substitution tilings with singular continuous spectrum
Creators: name: Baake, Michael
name: Grimm, Uwe
Publisher: name: arXiv
Year: 2012
Subjects: subject: Dynamical Systems (math.DS)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 52C23, 42B05

description: The squiral inflation rule is equivalent to a bijective block substitution rule and leads to an interesting lattice dynamical system under the action of $\mathbb{Z}^{2}$. In particular, its balanced version has purely singular continuous diffraction. The dynamical spectrum is of mixed type, with pure point and singular continuous components. We present a constructive proof that admits a generalisation to bijective block substitutions of trivial height on $\mathbb{Z}^{d}$.
description: 23 pages, 7 figures