cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Factors controlling the energetics of the oxygen reduction reaction on the Pd-Co electro-catalysts: Insight from first principles
Creators: name: Zuluaga, Sebastian
name: Stolbov, Sergey
Publisher: name: arXiv
Year: 2011
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report here results of our density functional theory based computational studies of the electronic structure of the Pd-Co alloy electrocatalysts and energetics of the oxygen reduction reaction (ORR) on their surfaces. The calculations have been performed for the (111) surfaces of pure Pd, Pd0.75Co0.25 and Pd0.5Co0.5 alloys, as well as of the surface segregated Pd/Pd0.75Co0.25 alloy. We find the hybridization of dPd and dCo electronic states to be the main factor controlling the electrocatalytic properties of Pd/Pd0.75Co0.25. Namely the dPd - dCo hybridization causes low energy shift of the surface Pd d-band with respect to that for Pd(111). This shift weakens chemical bonds between the ORR intermediates and the Pd/Pd0.75Co0.25 surface, which is favorable for the reaction. Non-segregated Pd0.75Co0.25 and Pd0.5Co0.5 surfaces are found to be too reactive for ORR due to bonding of the intermediates to the surface Co atoms. Analysis of the ORR free energy diagrams, built for the Pd and Pd/Pd0.75Co0.25, shows that the co-adsorption of the ORR intermediates and water changes the ORR energetics significantly and makes ORR more favorable. We find the onset ORR potential estimated for the configurations with the O - OH and OH - OH co-adsorption to be in very good agreement with experiment. The relevance of this finding to the real reaction environment is discussed.
Photometric search for variable stars in young open cluster Berkeley 59
Creators: name: Lata, Sneh
name: Pandey, A. K.
name: G., Maheswar
name: Mondal, Soumen
name: Kumar, Brijesh
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present time-series photometry of stars located in the extremely young open cluster Berkeley 59. Using the 1.04 m telescope at ARIES, Nainital, we have identified 42 variables in a field of 13'x13' around the cluster. The probable members of the cluster are identified using (V, V-I) colour-magnitude diagram and (J-H, H-K) colour-colour diagram. Thirty one variables are found to be pre-main sequence stars associated with the cluster. The ages and masses of pre-main sequence stars are derived from colour-magnitude diagram by fitting theoretical models to the observed data points. The ages of the majority of the probable pre-main sequence variable candidates range from 1 to 5 Myrs. The masses of these pre-main sequence variable stars are found to be in the range of ~0.3 to ~3.5 Msun and these could be T Tauri stars. The present statistics reveal that about 90% T Tauri stars have periods < 15 days. The classical T Tauri stars are found to have larger amplitude in comparison to the weak line T Tauri stars. There is an indication that the amplitude decreases with increase of the mass, which could be due to the dispersal of disk of relatively massive stars.
description: 11 pages, 12 Figures and 2 tables, Accepted for publication in MNRAS
Testing charge-radius coupling of the composite Higgs boson at hadron colliders
Creators: name: Cacciapaglia, G.
name: Gascon-Shotkin, S.
name: Lesauvage, A.
name: Manglani, N.
name: Sridhar, K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We explore the collider relevance of a charge-radius coupling among light mesons in composite Higgs models. In particular, we focus of a coupling of the photon to the composite Higgs and a composite singlet, arising from isospin violation in the underlying theory. This coupling offers a deep probe of the composite nature of the Higgs mechanism, being sensitive to the electromagnetic and weak isospin structure of its constituents. The main collider effect consists in the production of the Higgs boson in association with a light composite pseudo-scalar. We present an exploratory cut-and-count analysis at hadron colliders, like the LHC, showing that an efficient background suppression can be achieved. More sophisticated techniques, however, are necessary to select a sufficient number of signal events, due to the small production rates. This justifies further investigation of this channel, which is highly complementary to other searches for compositeness in the Higgs sector.
Generalized uncertainty principles and localization in discrete space
Creators: name: Bojowald, Martin
name: Kempf, Achim
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Generalized uncertainty principles are able to serve as useful descriptions of some of the phenomenology of quantum gravity effects, providing an intuitive grasp on non-trivial space-time structures such as a fundamental discreteness of space, a universal bandlimit or an irreducible extendedness of elementary particles. In this article, uncertainty relations are derived by a moment expansion of states for quantum systems with a discrete coordinate, and correspondingly a periodic momentum. Corrections to standard uncertainty relations are found, with some similarities but also key differences to what is often assumed in this context. The relations provided can be applied to discrete models of matter or space-time, including loop quantum cosmology.
description: 26 pages
A Geometric Kinematic Model for Flexible Voxel-Based Robots
Creators: name: Tebyani, Maryam
name: Spaeth, Alex
name: Cramer, Nicholas
name: Teodorescu, Mircea
Publisher: name: arXiv
Year: 2021
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Voxel-based structures provide a modular, mechanically flexible periodic lattice which can be used as a soft robot through internal deformations. To engage these structures for robotic tasks, we use a finite element method to characterize the motion caused by deforming single degrees of freedom and develop a reduced kinematic model. We find that node translations propagate periodically along geometric planes within the lattice, and briefly show that translational modes dominate the energy usage of the actuators. The resulting kinematic model frames the structural deformations in terms of user-defined control and end effector nodes, which further reduces the model size. The derived Planes of Motion (POM) model can be equivalently used for forward and inverse kinematics, as demonstrated by the design of a tripod stable gait for a locomotive voxel robot and validation of the quasi-static model through physical experiments.
description: 10 pages, 7 figures
Petersen, Jan. Gamle gårdsanlegg i Rogaland. (Alte Hofanlagen in Rogaland). Fortsetzung
Creators: name: Jacob-Friesen, Karl Hermann
Publisher: name: Nachrichten aus Niedersachsens Urgeschichte
Year: 2020

description: Rezension zu: Petersen, Jan. Gamle gårdsanlegg i Rogaland. (Alte Hofanlagen in Rogaland). Fortsetzung. Institut für vergleichende Kulturforschung Oslo Serie B. XXXI. 1936, 4°, 100 Seiten, 65 Tafeln. Oslo 1936. H. Aschehoug & Co. (W. Nygaard)
description: Nachrichten aus Niedersachsens Urgeschichte, Bd. 10 (1936): Nachrichten aus Niedersachsens Urgeschichte
Winthuis, J. Mythos und Kult der Steinzeit
Creators: name: Asmus, Wolfgang-Dietrich
Publisher: name: Nachrichten aus Niedersachsens Urgeschichte
Year: 2020

description: Rezension zu: Winthuis, J. Mythos und Kult der Steinzeit. Stuttgart 1935. Verlag Strecker und Schröder
description: Nachrichten aus Niedersachsens Urgeschichte, Bd. 10 (1936): Nachrichten aus Niedersachsens Urgeschichte
Kapazitätsplanung bei zufälligem Auftragseingang und -umfang
Creators: name: Krappinger, Odo
Publisher: name: TUHH Universitätsbibliothek
Year: 1990
Subjects: classificationCode: 52.00
subject: Maschinenbau, Energietechnik, Fertigungstechnik: Allgemeines

description: Kapazitätsplanung bei zufälligem Auftragseingang und -umfang
Metallo-dielectric hybrid antennas for ultrastrong enhancement of spontaneous emission
Creators: name: Chen, Xue-Wen
name: Agio, Mario
name: Sandoghdar, Vahid
Publisher: name: arXiv
Year: 2012
Subjects: subject: Optics (physics.optics)
subject: Atomic Physics (physics.atom-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We devise new optical antennas that reduce the excited-state radiative lifetimes of emitters to the order of 100 femtoseconds while maintaining quantum efficiencies of about 80% at a broadband operation. Here, we combine metallic nanoparticles with planar dielectric structures and exploit design strategies from plasmonic nanoantennas and concepts from Cavity Quantum Electrodynamics to maximize the local density of states and minimize the nonradiative losses incurred by the metallic constituents. The proposed metallo-dielectric hybrid antennas promise important impact on various fundamental and applied research fields, including photophysics, ultrafast plasmonics, bright single photon sources and Raman spectroscopy.
Strong lens systems search in the Dark Energy Survey using Convolutional Neural Networks
Creators: name: Rojas, K.
name: Savary, E.
name: Clément, B.
name: Maus, M.
name: Courbin, F.
name: Lemon, C.
name: Chan, J. H. H.
name: Vernardos, G.
name: Joseph, R.
name: Cañameras, R.
name: Galan, A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We performed a search for strong lens galaxy-scale systems in the first data release of the Dark Energy Survey (DES), from a color-selected parent sample of 18~745~029 Luminous Red Galaxies (LRGs). Our search was based on a Convolutional Neural Network (CNN) to grade our LRG selection with values between 0 (non-lens) and 1 (lens). Our training set was data-driven, i.e. using lensed sources taken from HST COSMOS images and where the light distribution of the lens plane was taken directly from DES images of our LRGs. A total of 76~582 cutouts obtained a score above 0.9. These were visually inspected and resulted in two catalogs. The first one contains 405 lens candidates, where 90 present clear lensing features and counterparts, while the others 315 require more evidence, such as higher resolution images or spectra to be conclusive. A total of 186 candidates were totally new identified in this search. The second catalog includes 539 ring galaxy candidates that will be useful to train CNNs against this type of false positives. For the 90 best lens candidates we carried out color-based deblending of the lens and source light without fitting any analytical profile to the data. The method turned out to be very efficient in the deblending, even for very compact objects and for objects with very complex morphology. Finally, from the 90 best lens candidates we selected 52 systems having one single deflector, to test an automated modeling pipeline which successfully modeled 79\% of the sample within an acceptable amount of computing time.
description: 37 pages, 31 figures, submitted to A&A
Inertial spin dynamics in epitaxial cobalt films
Creators: name: Unikandanunni, Vivek
name: Medapalli, Rajasekhar
name: Asa, Marco
name: Albisetti, Edoardo
name: Petti, Daniela
name: Bertacco, Riccardo
name: Fullerton, Eric E.
name: Bonetti, Stefano
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate the spin dynamics driven by terahertz magnetic fields in epitaxial thin films of cobalt in its three crystalline phases. The terahertz magnetic field generates a torque on the magnetization which causes it to precess for about 1 ps, with a sub-picosecond temporal lag from the driving force. Then, the magnetization undergoes natural damped THz oscillations at a frequency characteristic of the crystalline phase. We describe the experimental observations solving the inertial Landau-Lifshitz-Gilbert equation. Using the results from the relativistic theory of magnetic inertia, we find that the angular momentum relaxation time $η$ is the only material parameter needed to describe all the experimental evidence. Our experiments suggest a proportionality between $η$ and the strength of the magneto-crystalline anisotropy.
description: 6 pages, 4 figures, Supplemental Material
Electron Distribution in the Galactic Disk - Results From a Non-Equilibrium Ionization Model of the ISM
Creators: name: de Avillez, M. A.
name: Asgekar, A.
name: Breitschwerdt, D.
name: Spitoni, E.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Using three-dimensional non-equilibrium ionization (NEI) hydrodynamical simulation of the interstellar medium (ISM), we study the electron density, $n_{e}$, in the Galactic disk and compare it with the values derived from dispersion measures towards pulsars with known distances located up to 200 pc on either side of the Galactic midplane. The simulation results, consistent with observations, can be summarized as follows: (i) the DMs in the simulated disk lie between the maximum and minimum observed values, (ii) the log derived from lines of sight crossing the simulated disk follows a Gaussian distribution centered at μ=-1.4 with a dispersion σ=0.21, thus, the Galactic midplane =0.04\pm 0.01$ cm$^{-3}$, (iii) the highest electron concentration by mass (up to 80%) is in the thermally unstable regime (200
description: Letter accepted for publication in Monthly Notices of the Royal Astronomical Society
Non-Locality$\neq$Quantum Entanglement
Creators: name: Guo, Xingyu
name: Ma, Chen-Te
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The unique entanglement measure is concurrence in a 2-qubit pure state. The maximum violation of Bell's inequality is monotonically increasing for this quantity. Therefore, people expect that pure state entanglement is relevant to the non-locality. For justification, we extend the study to three qubits. We consider all possible 3-qubit operators with a symmetric permutation. When only considering one entanglement measure, the numerical result contradicts expectation. Therefore, we conclude ``Non-Locality$\neq$Quantum Entanglement''. We propose the generalized $R$-matrix or correlation matrix for the new diagnosis of Quantum Entanglement. We then demonstrate the evidence by restoring the monotonically increasing result.
description: 38 pages, 10 figures, minor changes, reference added
Observational signatures of particle acceleration in supernova remnants
Creators: name: Helder, E. A.
name: Vink, J.
name: Bykov, A. M.
name: Ohira, Y.
name: Raymond, J. C.
name: Terrier, R.
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 evaluate the current status of supernova remnants as the sources of Galactic cosmic rays. We summarize observations of supernova remnants, covering the whole electromagnetic spectrum and describe what these obser- vations tell us about the acceleration processes by high Mach number shock fronts. We discuss the shock modification by cosmic rays, the shape and maximum energy of the cosmic-ray spectrum and the total energy budget of cosmic rays in and surrounding supernova remnants. Additionally, we discuss problems with supernova remnants as main sources of Galactic cosmic rays, as well as alternative sources.
description: Accepted for publication by Space Science Reviews, 81 pages
Wie archiviert man immaterielles Kulturgut
Creators: name: Neidhöfer, Andrea
Publisher: name: AKMB-news: Informationen zu Kunst, Museum und Bibliothek
Year: 2020

description: AKMB-news: Informationen zu Kunst, Museum und Bibliothek, Bd. 25 Nr. 1 (2019): AKMB-news
HYPE with stochastic events
Creators: name: Bortolussi, Luca
name: Galpin, Vashti
name: Hillston, Jane
Publisher: name: arXiv
Year: 2011
Subjects: subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences

description: The process algebra HYPE was recently proposed as a fine-grained modelling approach for capturing the behaviour of hybrid systems. In the original proposal, each flow or influence affecting a variable is modelled separately and the overall behaviour of the system then emerges as the composition of these flows. The discrete behaviour of the system is captured by instantaneous actions which might be urgent, taking effect as soon as some activation condition is satisfied, or non-urgent meaning that they can tolerate some (unknown) delay before happening. In this paper we refine the notion of non-urgent actions, to make such actions governed by a probability distribution. As a consequence of this we now give HYPE a semantics in terms of Transition-Driven Stochastic Hybrid Automata, which are a subset of a general class of stochastic processes termed Piecewise Deterministic Markov Processes.
description: In Proceedings QAPL 2011, arXiv:1107.0746
100 Jahre Bauhaus – ein Roman über die Anfänge in Weimar und was aus den Protagonisten wurde
Creators: name: Gierke, Bettina
Publisher: name: AKMB-news: Informationen zu Kunst, Museum und Bibliothek
Year: 2020

description: AKMB-news: Informationen zu Kunst, Museum und Bibliothek, Bd. 25 Nr. 1 (2019): AKMB-news
Quantitative Evidence for an Intrinsic Age Spread in the Orion Nebula Cluster
Creators: name: Reggiani, M.
name: Robberto, M.
name: Da Rio, N.
name: Meyer, M. R.
name: Soderblom, D. R.
name: Ricci, L.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Aims. We present a study of the distribution of stellar ages in the Orion Nebula Cluster (ONC) based on accurate HST photometry taken from the HST Treasury Program observations of the ONC utilizing the most recent estimate of the cluster's distance (Menten et al. 2007). We investigate the presence of an intrinsic age spread in the region and a possible trend of age with the spatial distribution. Methods. We estimate the extinction and accretion luminosity towards each source by performing synthetic photometry on an empirical calibration of atmospheric models (Da Rio et al. 2010) using the package Chorizos (Maiz-Apellaniz 2004). The position of the sources in the HR-diagram is compared with different theoretical isochrones to estimate the mean cluster age and age dispersion. Through Monte Carlo simulations we quantify the amount of intrinsic age spread in the region, taking into account uncertainties on the distance, spectral type, extinction, unresolved binaries, accretion and photometric variability. Results. According to Siess et al. (2000) evolutionary models the mean age of the Cluster is 2.2 Myr with a scatter of few Myrs. With Monte Carlo simulations we find that the observed age spread is inconsistent with a coeval stellar population, but is in agreement with a star formation activity between 1.5 and 3.5 Myrs. We also observe light evidence for a trend of ages with spatial distribution.
description: 12 pages, 12 figures, Accepted for publication in Astronomy and Astrophysics
Left-right splitting of elliptic flow due to directed flow in heavy ion collisions
Creators: name: Zhang, Chao
name: Lin, Zi-Wei
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Recently the splitting of elliptic flow $v_2$ at finite rapidities has been proposed as a result of the global vorticity in non-central relativistic heavy ion collisions. In this study, we find that this left-right (i.e., on opposite sides of the impact parameter axis) splitting of the elliptic flow at finite rapidities is a result of the non-zero directed flow $v_1$, with the splitting magnitude $\approx 8v_1(1-3v_2)/(3π)$. We also use a multi-phase transport model, which automatically includes the vorticity field and flow fluctuations, to confirm the $v_2$ splitting. In addition, we find that the analytical expectations for the $v_2$ splitting work for the raw $v_2$ and $v_1$ (i.e., before event plane resolutions are applied) measured relative to either the first- or second-order event plane. Since the $v_2$ splitting is mostly driven by $v_1$, it vanishes at zero transverse momentum ($p_{\rm T}$), and its magnitude and sign may have non-trivial dependencies on $p_{\rm T}$, centrality, collision energy, and hadron species.
description: 8 pages, 10 figures; v2 splitting results are now shown to 2nd order, added a new section with six figures to show results from the event plane method
D-module Representations of N=2,4,8 Superconformal Algebras and Their Superconformal Mechanics
Creators: name: Kuznetsova, Zhanna
name: Toppan, Francesco
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The linear (homogeneous and inhomogeneous) (k, N, N-k) supermultiplets of the N-extended one-dimensional Supersymmetry Algebra induce D-module representations for the N=2,4,8 superconformal algebras. For N=2, the D-module representations of the A(1,0) superalgebra are obtained. For N=4 and scaling dimension λ=0, the D-module representations of the A(1,1) superalgebra are obtained. For $λ\neq 0$, the D-module representations of the D(2,1;α) superalgebras are obtained, with $α$ determined in terms of the scaling dimension $λ$ according to: $α=-2λ$ for k=4, i.e. the (4,4) supermultiplet, $α=-λ$ for k=3, i.e. (3,4,1), and $α=λ$ for k=1, i.e. (1,4,3). For $λ\neq 0$ the (2,4,2) supermultiplet induces a D-module representation for the centrally extended sl(2|2) superalgebra. For N=8, the (8,8) root supermultiplet induces a D-module representation of the D(4,1) superalgebra at the fixed value $λ=1/4$. A Lagrangian framework to construct one-dimensional, off-shell, superconformal invariant actions from single-particle and multi-particles D-module representations is discussed. It is applied to explicitly construct invariant actions for the homogeneous and inhomogeneous N=4 (1,4,3) D-module representations (in the last case for several interacting supermultiplets of different chirality).
description: 22 pages
Nanoscale Metallic Iron for Environmental Remediation: Prospects and Limitations
Creators: name: Noubactep, Chicgoua
name: Caré, Sabine
name: Crane, Richard
Publisher: name: arXiv
Year: 2012
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: The amendment of the subsurface with nanoscale metallic iron particles (nano-Fe0) has been discussed in the literature as an efficient in situ technology for groundwater remediation. However, the introduction of this technology was controversial and its efficiency has never been univocally established. This unsatisfying situation has motivated this communication whose objective was a comprehensive discussion of the intrinsic reactivity of nano-Fe0 based on the contemporary knowledge on the mechanism of contaminant removal by Fe0 and a mathematical model. It is showed that due to limitations of the mass transfer of nano-Fe0 to contaminants, available concepts cannot explain the success of nano-Fe0 injection for in situ groundwater remediation. It is recommended to test the possibility of introducing nano-Fe0 to initiate the formation of roll-fronts which propagation would induce the reductive transformation of both dissolved and adsorbed contaminants. Within a roll-front, FeII from nano-Fe0 is the reducing agent for contaminants. FeII is recycled by biotic or abiotic FeIII reduction. While the roll-front concept could explain the success of already implemented reaction zones, more research is needed for a science-based recommendation of nano- Fe0 for subsurface treatment by roll-fronts
Renate Tölle-Kastenbein, Frühklassische Peplosfiguren. Originale
Creators: name: Sismondo Ridgway, Brunilde
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Renate Tölle-Kastenbein, Frühklassische Peplosfiguren. Originale. Verlag Philipp von Zabern, Mainz 1980. 2 vols. Text: IV + 247 pp. wich 35 ills.; Plates: 176.
description: Bonner Jahrbücher, Bd. 182.1982: Bonner Jahrbücher
Hans-Georg Pflaum, Les fastes de la province de Narbonnaise
Creators: name: Petersen, Leiva
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Hans-Georg Pflaum, Les fastes de la province de Narbonnaise, mit einem Vorwort von A. Grenier. Gallia, Supplement 30. Centre National de la Recherche Scientifique, Paris 1978, 514 Seiten.
description: Bonner Jahrbücher, Bd. 182.1982: Bonner Jahrbücher
Magnetic field decay with Hall drift in neutron star crusts
Creators: name: Kojima, Yasufumi
name: Kisaka, Shota
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The dynamics of magnetic field decay with Hall drift is investigated. Assuming that axisymmetric magnetic fields are located in a spherical crust with uniform conductivity and electron number density, long-term evolution is calculated up to Ohmic dissipation. The nonlinear coupling between poloidal and toroidal components is explored in terms of their energies and helicity. Nonlinear oscillation by the drift in strongly magnetized regimes is clear only around the equipartition between two components. Significant energy is transferred to the poloidal component when the toroidal component initially dominates. However, the reverse is not true. Once the toroidal field is less dominant, it quickly decouples due to a larger damping rate. The polar field at the surface is highly distorted from the initial dipole during the Hall drift timescale, but returns to the initial dipole in a longer dissipation timescale, since it is the least damped one.
description: 11 pages, 9 figures
Lorenzo Quilici und Stefania Quilici Gigli, Antemnae
Creators: name: Steingräber, Stephan
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Lorenzo Quilici und Stefania Quilici Gigli, Antemnae. Latium vetus 1. Centro di studi perl'archeologia etrusco-italica, Rom 1978. XVI und 182 Seiten, 58 Tafeln.
description: Bonner Jahrbücher, Bd. 182.1982: Bonner Jahrbücher
Length Regulation Drives Self-Organization in Filament-Motor Mixtures
Creators: name: Striebel, Moritz
name: Brauns, Fridtjof
name: Frey, Erwin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: Cytoskeletal networks form complex intracellular structures. Here we investigate a minimal model for filament-motor mixtures in which motors act as depolymerases and thereby regulate filament length. Combining agent-based simulations and hydrodynamic equations, we show that resource-limited length regulation drives the formation of filament clusters despite the absence of mechanical interactions between filaments. Even though the orientation of individual remains fixed, collective filament orientation emerges in the clusters, aligned orthogonal to their interfaces.
description: Merged manuscript + SI, Movies S1 and S2 in source file
Gisela Jeremias, Die Holztür der Basilika S. Sabina in Rom
Creators: name: Brenk, Beat
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Gisela Jeremias, Die Holztür der Basilika S. Sabina in Rom. Bilderhefte des Deutschen Archäologischen Instituts Rom, Heft 7. Verlag Wasmuth, Tübingen 1980. 166 Seiten, 80 Tafeln.
description: Bonner Jahrbücher, Bd. 182.1982: Bonner Jahrbücher
From Quantum Groups to Liouville and Dilaton Quantum Gravity
Creators: name: Fan, Yale
name: Mertens, Thomas G.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Quantum Algebra (math.QA)
subject: Representation Theory (math.RT)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We investigate the underlying quantum group symmetry of 2d Liouville and dilaton gravity models, both consolidating known results and extending them to the cases with $\mathcal{N} = 1$ supersymmetry. We first calculate the mixed parabolic representation matrix element (or Whittaker function) of $\text{U}_q(\mathfrak{sl}(2, \mathbb{R}))$ and review its applications to Liouville gravity. We then derive the corresponding matrix element for $\text{U}_q(\mathfrak{osp}(1|2, \mathbb{R}))$ and apply it to explain structural features of $\mathcal{N} = 1$ Liouville supergravity. We show that this matrix element has the following properties: (1) its $q\to 1$ limit is the classical $\text{OSp}^+(1|2, \mathbb{R})$ Whittaker function, (2) it yields the Plancherel measure as the density of black hole states in $\mathcal{N} = 1$ Liouville supergravity, and (3) it leads to $3j$-symbols that match with the coupling of boundary vertex operators to the gravitational states as appropriate for $\mathcal{N} = 1$ Liouville supergravity. This object should likewise be of interest in the context of integrability of supersymmetric relativistic Toda chains. We furthermore relate Liouville (super)gravity to dilaton (super)gravity with a hyperbolic sine (pre)potential. We do so by showing that the quantization of the target space Poisson structure in the (graded) Poisson sigma model description leads directly to the quantum group $\text{U}_q(\mathfrak{sl}(2, \mathbb{R}))$ or the quantum supergroup $\text{U}_q(\mathfrak{osp}(1|2, \mathbb{R}))$.
description: 66 pages, v4: fixed further typos
J. Ramin, La technique minière et metallurgique des Anciens / J. F. Healy, Mining and Metallurgy in the Greek and Roman World. Aspects of Greek and Roman Life
Creators: name: Raub, Christoph
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: J. Ramin, La technique minière et metallurgique des Anciens. Mit einem Vorwort von R. Chevallier. Collection Latomus 153. Edition Latomus, Brüssel 1977. 223 Seiten. J. F. Healy, Mining and Metallurgy in the Greek and Roman World. Aspects of Greek and Roman Life. Verlag Thames and Hudson, London 1978. 316 Seiten, 73 Abbildungen, 28 Strichzeichnungen, 2 Karten.
description: Bonner Jahrbücher, Bd. 182.1982: Bonner Jahrbücher
Sarah Macready und F. H. Thompson (Hrsg.), Cross-Channel Trade between Gaul and Britain in the Pre-Roman Iron Age
Creators: name: Joachim, Hans-Eckart
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Sarah Macready und F. H. Thompson (Hrsg.), Cross-Channel Trade between Gaul and Britain in the Pre-Roman Iron Age. The Society of Antiquaries of London, Occasional Paper NS IV, London 1984. 1 14 Seiten, 26 Abbildungen.
description: Bonner Jahrbücher, Bd. 185.1985: Bonner Jahrbücher
Bernhard Schmaltz, Griechische Grabreliefs
Creators: name: Stupperich, Reinhard
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Bernhard Schmaltz, Griechische Grabreliefs. Erträge der Forschung 192. Wissenschaftliche Buchgesellschaft, Darmstadt 1983. XXI, 252 Seiten, 11 Textabbildungen, 32 Tafeln.
description: Bonner Jahrbücher, Bd. 185.1985: Bonner Jahrbücher
Classifying minimum energy states for interacting particles: Regular simplices
Creators: name: Davies, Cameron
name: Lim, Tongseok
name: McCann, Robert J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: Optimization and Control (math.OC)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: Primary 49Q10. Secondary 31B10, 35Q70, 37L30, 70F45, 90C20

description: Densities of particles on $\Rn$ which interact pairwise through an attractive-repulsive power-law potential $W_{\al,\bt}(x) = |x|^\al/\al-|x|^\bt/\bt$ have often been used to explain patterns produced by biological and physical systems. In the mildly repulsive regime $\al> \bt \ge 2$ with $n \ge 2$, we show there exists a decreasing homeomorphism $\al_{Δ^n}$ from $[2,4]$ to itself such that: distributing the particles uniformly over the vertices of a regular unit diameter $n$-simplex minimizes the potential energy if and only if $\al\ge \al_{\De^n}(\bt)$. Moreover this minimum is uniquely attained up to rigid motions when $\al > \al_{\De^n}(\bt)$. We estimate $\al_{\De^n}(\bt)$ above and below, and identify its limit as the dimension grows large. These results are derived from a new northeast comparison principle in the space of exponents. At the endpoint $(\al,\bt)=(4,2)$ of this transition curve, we characterize all minimizers by showing they lie on a sphere and share all first and second moments with the spherical shell. Suitably modified versions of these statements are also established (i) for $W_{α,β}$ and corresponding energies in the case where $n=1$, and (ii) for the attractive-repulsive potentials $D_\al(x) = |x|^\al(\al\log |x|-1)$ that arise in the limit $\bt \nearrow \al$.
description: Reference [15] has been added and Remark 1.6 revised in ver2. v3 updates its content and title and will be published in Comm.Math.Phys
Rolf A. Stucky, Tribüne d’Echmoun. Ein griechischer Reliefzyklus des 4. Jahrhunderts in Sidon
Creators: name: Linfert, Andreas
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Rolf A. Stucky, Tribüne d’Echmoun. Ein griechischer Reliefzyklus des 4. Jahrhunderts in Sidon. Antike Kunst Beiheft 13. Basel 1984. 84 Seiten, 18 Tafeln, 1 Falttafel (zus. 60 Abbildungen).
description: Bonner Jahrbücher, Bd. 185.1985: Bonner Jahrbücher
Arminda Lozano, La esclavitud en Asia Menor Helenística
Creators: name: Backhaus, Wilhelm
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Arminda Lozano, La esclavitud en Asia Menor Helenística. Estudios de Historia Antigua 1. Asociación Trajano y Departamento de Historia Antigua. Universidad de Oviedo [o. J., 1981], 324 Seiten.
description: Bonner Jahrbücher, Bd. 185.1985: Bonner Jahrbücher
A comment on lepton mixing
Creators: name: Metaxas, Dimitrios
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Since right-handed neutrinos, if added to the Standard Model, have no gauge interactions, their kinetic terms can be mixed. I examine the related rotations of the gauge eigenstates in order to derive the propagators for the kinetic and mass terms, and I comment on the resulting lepton mixing, on the possibility of not having well-defined mass eigenstates, and on the modifications to weak contributions and observables (anomalous magnetic moment, muon decay, neutrino oscillations).
description: Comments and references added, accepted in EPL
Far-infrared Spectral Energy Distribution Fitting for Galaxies Near and Far
Creators: name: Casey, Caitlin M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Spectral Energy Distribution (SED) fitting in the far-infrared (FIR) is greatly limited by a dearth of data and an excess of free parameters - from galaxies' dust composition, temperature, mass, orientation, opacity, to heating from AGN. This paper presents a simple FIR SED fitting technique joining a modified, single dust temperature greybody, representing the reprocessed starburst emission in the whole galaxy, to a mid-infrared powerlaw, which approximates hot-dust emission from AGN heating or clumpy, hot starbursting regions. This FIR SED can be used to measure infrared luminosities, dust temperatures and dust masses for both local and high-z galaxies with 3 to 10+ FIR photometric measurements. This fitting method is compared to infrared template SEDs in the literature using photometric data on 65 local luminous and ultraluminous infrared galaxies, (U)LIRGs. Despite relying only on 2-4 free parameters, the coupled greybody/powerlaw SED fitting described here produces better fits to photometric measurements than best-fit literature template SEDs (with residuals a factor of ~2 lower). A mean emissivity index of beta=1.60+-0.38 and mid-infrared powerlaw slope of alpha=2.0+-0.5 is measured; the former agrees with the widely presumed emissivity index of beta=1.5 and the latter is indicative of an optically-thin dust medium with a shallow radial density profile, ~r^-0.5. Adopting characteristic dust temperature as the inverse wavelength where the SED peaks, dust temperatures ~25-45K are measured for local (U)LIRGs, ~5-15K colder than previous estimates using only simple greybodies. This comparative study highlights the impact of SED fitting assumptions on the measurement of physical properties such as infrared luminosity (and thereby infrared-based star formation rate), dust temperature and dust mass, for both local and high-redshift galaxies. [abridged]
description: 12 pages, 7 figures, MNRAS accepted
Helmuth Schneider (Hrsg.), Sozial- und Wirtschaftsgeschichte der römischen Kaiserzeit
Creators: name: Schneider, Hans-Christian
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Helmuth Schneider (Hrsg.), Sozial- und Wirtschaftsgeschichte der römischen Kaiserzeit. Wege der Forschung 552. Wissenschaftliche Buchgesellschaft, Darmstadt 1981. 460 Seiten.
description: Bonner Jahrbücher, Bd. 185.1985: Bonner Jahrbücher
Dorothee Renner, Die koptischen Textilien in den Vatikanischen Museen
Creators: name: Simon, Erika
Publisher: name: Bonner Jahrbücher
Year: 2020

description: Rezension zu: Dorothee Renner, Die koptischen Textilien in den Vatikanischen Museen. Monumenti, Musei e Gallerie Pontificie, Pinacoteca Vaticana, Kataloge Band 2. Franz Steiner Verlag, Wiesbaden 1982. 154 Seiten, 6 Farbtafeln, 56 Schwarzweißtafeln.
description: Bonner Jahrbücher, Bd. 185.1985: Bonner Jahrbücher
Average-Case Verification of the Quantum Fourier Transform Enables Worst-Case Phase Estimation
Creators: name: Linden, Noah
name: de Wolf, Ronald
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The quantum Fourier transform (QFT) is a key primitive for quantum computing that is typically used as a subroutine within a larger computation, for instance for phase estimation. As such, we may have little control over the state that is input to the QFT. Thus, in implementing a good QFT, we may imagine that it needs to perform well on arbitrary input states. Verifying this worst-case correct behaviour of a QFT-implementation would be exponentially hard (in the number of qubits) in general, raising the concern that this verification would be impossible in practice on any useful-sized system. In this paper we show that, in fact, we only need to have good average-case performance of the QFT to achieve good worst-case performance for key tasks -- phase estimation, period finding and amplitude estimation. Further we give a very efficient procedure to verify this required average-case behaviour of the QFT.
description: 18 pages LaTeX. Version 3: small changes for final version that will appear in Quantum
An asteroseismic membership study of the red giants in three open clusters observed by Kepler: NGC6791, NGC6819, and NGC6811
Creators: name: Stello, D.
name: Meibom, S.
name: Gilliland, R. L.
name: Grundahl, F.
name: Hekker, S.
name: Mosser, B.
name: Kallinger, T.
name: Mathur, S.
name: García, R. A.
name: Huber, D.
name: Basu, S.
name: Bedding, T. R.
name: Brogaard, K.
name: Chaplin, W. J.
name: Elsworth, Y. P.
name: Molenda-Żakowicz, J.
name: Szabó, R.
name: Still, M.
name: Jenkins, J. M.
name: Christensen-Dalsgaard, J.
name: Kjeldsen, H.
name: Serenelli, A. M.
name: Wohler, B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Studying star clusters offers significant advances in stellar astrophysics due to the combined power of having many stars with essentially the same distance, age, and initial composition. This makes clusters excellent test benches for verification of stellar evolution theory. To fully exploit this potential, it is vital that the star sample is uncontaminated by stars that are not members of the cluster. Techniques for determining cluster membership therefore play a key role in the investigation of clusters. We present results on three clusters in the Kepler field of view based on a newly established technique that uses asteroseismology to identify fore- or background stars in the field, which demonstrates advantages over classical methods such as kinematic and photometry measurements. Four previously identified seismic non-members in NGC6819 are confirmed in this study, and three additional non-members are found -- two in NGC6819 and one in NGC6791. We further highlight which stars are, or might be, affected by blending, which needs to be taken into account when analysing these Kepler data.
description: 12 pages, 9 figures, 5 tables, accepted by ApJ
Natural selection. IV. The Price equation
Creators: name: Frank, Steven A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: The Price equation partitions total evolutionary change into two components. The first component provides an abstract expression of natural selection. The second component subsumes all other evolutionary processes, including changes during transmission. The natural selection component is often used in applications. Those applications attract widespread interest for their simplicity of expression and ease of interpretation. Those same applications attract widespread criticism by dropping the second component of evolutionary change and by leaving unspecified the detailed assumptions needed for a complete study of dynamics. Controversies over approximation and dynamics have nothing to do with the Price equation itself, which is simply a mathematical equivalence relation for total evolutionary change expressed in an alternative form. Disagreements about approach have to do with the tension between the relative valuation of abstract versus concrete analyses. The Price equation's greatest value has been on the abstract side, particularly the invariance relations that illuminate the understanding of natural selection. Those abstract insights lay the foundation for applications in terms of kin selection, information theory interpretations of natural selection, and partitions of causes by path analysis. I discuss recent critiques of the Price equation by Nowak and van Veelen.
Field O stars: formed in situ or as runaways?
Creators: name: Gvaramadze, V. V.
name: Weidner, C.
name: Kroupa, P.
name: Pflamm-Altenburg, J.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: A significant fraction of massive stars in the Milky Way and other galaxies are located far from star clusters. It is known that some of these stars are runaways and therefore most likely were formed in embedded clusters and then ejected into the field because of dynamical few-body interactions or binary-supernova explosions. However, there exists a group of field O stars whose runaway status is difficult to prove via direct proper motion measurements or whose low space velocities and/or young ages appear to be incompatible with their large separation from known star clusters. The existence of this group led some authors to believe that field O stars can form in situ. In this paper, we examine the runaway status of the best candidates for isolated formation of massive stars in the Milky Way and the Magellanic Clouds by searching for bow shocks around them, by using the new reduction of the Hipparcos data, and by searching for stellar systems from which they could originate within their lifetimes. We show that most of the known O stars thought to have formed in isolation are instead very likely runaways. We show also that the field must contain a population of O stars whose low space velocities and/or young ages are in apparent contradiction with the large separation of these stars from their parent clusters and/or the ages of these clusters. These stars (the descendants of runaway massive binaries) cannot be traced back to their parent clusters and therefore can be mistakenly considered as having formed in situ. We argue also that some field O stars could be detected in optical wavelengths only because they are runaways, while their cousins residing in the deeply embedded parent clusters might still remain totally obscured. The main conclusion of our study is that there is no significant evidence whatsoever in support of the in situ proposal on the origin of massive stars.
description: 14 pages, 10 figures, 3 tables. Accepted for publication in MNRAS
Free Surface in 2D Potential Flow: Singularities, Invariants and Virtual Fluid
Creators: name: Dyachenko, A. I.
name: Dyachenko, S. A.
name: Zakharov, V. E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Mathematical Physics (math-ph)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences
subject: 76B07

description: We study a 2D potential flow of an ideal fluid with a free surface with decaying conditions at infinity. By using the conformal variables approach, we study a particular solution of Euler equations having a pair of square-root branch points in the conformal plane, and find that the analytic continuation of the fluid complex potential and conformal map define a flow in the entire complex plane, excluding a vertical cut between the branch points. The expanded domain is called the "virtual" fluid, and it contains a vortex sheet whose dynamics is equivalent to the equations of motion posed at the free surface. The equations of fluid motion are analytically continued to both sides of the vertical branch cut (the vortex sheet), and additional time-invariants associated with the topology of conformal plane and Kelvin's theorem for virtual fluid are explored. We called them "winding" and virtual circulation. This result can be generalized to a system of many cuts connecting many branch points, and resulting in a pair of invariants for each pair of branch points. We develop an asymptotic theory that shows how a solution originating from a single vertical cut forms a singularity at the free surface in infinite time, the rate of singularity approach is double-exponential, and supercedes the previous result of the short branch cut theory with finite time singularity formation. The present work offers a new look at fluid dynamics with free surface by unifying the problem of motion of vortex sheets, and the problem of 2D water waves. A particularly interesting question that arises in this context is whether instabilities of the virtual vortex sheet are related to breaking of steep ocean waves when gravity effects are included.