cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Orbital contributions to the electron g-factor in semiconductor nanowires
Creators: name: Winkler, Georg W.
name: Varjas, Dániel
name: Skolasinski, Rafal
name: Soluyanov, Alexey A.
name: Troyer, Matthias
name: Wimmer, Michael
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Recent experiments on Majorana fermions in semiconductor nanowires [Albrecht et al., Nat. 531, 206 (2016)] revealed a surprisingly large electronic Landé g-factor, several times larger than the bulk value - contrary to the expectation that confinement reduces the g-factor. Here we assess the role of orbital contributions to the electron g-factor in nanowires and quantum dots. We show that an LS coupling in higher subbands leads to an enhancement of the g-factor of an order of magnitude or more for small effective mass semiconductors. We validate our theoretical finding with simulations of InAs and InSb, showing that the effect persists even if cylindrical symmetry is broken. A huge anisotropy of the enhanced g-factors under magnetic field rotation allows for a straightforward experimental test of this theory.
description: Supplemental Material appended
A correction to a remark in a paper by Procacci and Yuhjtman: new lower bounds for the convergence radius of the virial series
Creators: name: Procacci, Aldo
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 82B05, 82B21

description: In this note we deduce a new lower bound for the convergence radius of the Virial series of a continuous system of classical particles interacting via a stable and tempered pair potential using the estimates on the Mayer coefficients obtained in the recent paper by Procacci and Yuhjtman (Lett Math Phys 107:31-46, 2017). This corrects the wrongly optimistic lower bound for the same radius claimed (but not proved) in the above cited paper (in Remark 2 below Theorem 1). The lower bound for the convergence radius of the Virial series provided here represents a strong improvement on the classical estimate given by Lebowitz and Penrose in 1964.
description: To appear in JSP
On the last stable orbit around rapidly rotating neutron stars
Creators: name: Cipolletta, Federico
name: Cherubini, Christian
name: Filippi, Simonetta
name: Rueda, Jorge A.
name: Ruffini, Remo
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We compute the binding energy and angular momentum of a test-particle at the last stable circular orbit (LSO) on the equatorial plane around a general relativistic, rotating neutron star (NS). We present simple, analytic, but accurate formulas for these quantities that fit the numerical results and which can be used in several astrophysical applications. We demonstrate the accuracy of these formulas for three different equations of state (EOS) based on nuclear relativistic mean-field theory models and argue that they should remain still valid for any NS EOS that satisfy current astrophysical constraints. We compare and contrast our numerical results with the corresponding ones for the Kerr metric characterized by the same mass and angular momentum.
description: Accepted for publication in Phys. Rev. D
Geodesics in nonexpanding impulsive gravitational waves with $Λ$, II
Creators: name: Sämann, Clemens
name: Steinbauer, Roland
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Physics (math-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences
subject: 83C15, 83C35, 46F30, 34A36

description: We investigate all geodesics in the entire class of nonexpanding impulsive gravitational waves propagating in an (anti-)de Sitter universe using the distributional metric. We extend the regularization approach of part I, [SSLP16] to a full nonlinear distributional analysis within the geometric theory of generalized functions. We prove global existence and uniqueness of geodesics that cross the impulsive wave and hence geodesic completeness in full generality for this class of low regularity spacetimes. This, in particular, prepares the ground for a mathematically rigorous account on the 'physical equivalence' of the continuous with the distributional `from' of the metric.
description: 21 pages, 1 figure; v2: close to final version
Generation of Coupled Monopoles and Gravity Waves in the Sun
Creators: name: Frost, Randall S.
Publisher: name: figshare
Year: 2023
Subjects: classificationCode: 519999
subject: Other physical sciences not elsewhere classified

description: It is shown that magnetic monopole rotations in the Sun generate a critical number of gravitons in one year. These gravitons are then converted into a gravity wave. The gravity wave couples to a (second) magnetic monopole that is generated by the rotation of an electron about the original monopole. The gravity wave couples to the generated monopole and the coupled pair leaves the Sun at the speed of light.
Rank two topological and infinitesimal embedded jump loci of quasi-projective manifolds
Creators: name: Papadima, Stefan
name: Suciu, Alexander I.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Algebraic Geometry (math.AG)
subject: Algebraic Topology (math.AT)
subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 14F35, 55N25, 20C15, 55P62

description: We study the germs at the origin of $G$-representation varieties and the degree 1 cohomology jump loci of fundamental groups of quasi-projective manifolds. Using the Morgan-Dupont model associated to a convenient compactification of such a manifold, we relate these germs to those of their infinitesimal counterparts, defined in terms of flat connections on those models. When the linear algebraic group $G$ is either $\textrm{SL}_2(\mathbb{C})$ or its standard Borel subgroup and the depth of the jump locus is 1, this dictionary works perfectly, allowing us to describe in this way explicit irreducible decompositions for the germs of these embedded jump loci. On the other hand, if either $G=\textrm{SL}_n(\mathbb{C})$ for some $n\ge 3$, or the depth is greater than 1, then certain natural inclusions of germs are strict.
description: 36 pages; accepted for publication in Journal of the Institute of Mathematics of Jussieu
Spectral flow for an integrable staggered superspin chain
Creators: name: Frahm, Holger
name: Hobuß, Konstantin
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The flow of the low energy eigenstates of a $U_q[sl(2|1)]$ superspin chain with alternating fundamental ($3$) and dual ($\bar{3}$) representations is studied as function of a twist angle determining the boundary conditions. The finite size spectrum is characterized in terms of scaling dimensions and quasi momenta representing the two families of commuting transfer matrices for the model which are even and odd under the interchange $3\leftrightarrow \bar{3}$, respectively. Based on the extrapolation of our finite size data we find that under a variation of the boundary conditions from periodic to antiperiodic for the fermionic degrees of freedom levels from the continuous part of the spectrum flow into discrete levels and vice versa.
description: 12 pages, 3 figures
Solvable Markovian dynamics of lattice quantum spin models
Creators: name: Mesterházy, D.
name: Hebenstreit, F.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We address the real-time dynamics of lattice quantum spin models coupled to single or multiple Markovian dissipative reservoirs using the method of closed hierarchies of correlation functions. This approach allows us to solve a number of quantum spin models exactly in arbitrary dimensions, which is illustrated explicitly with two examples of driven-dissipative systems. We investigate their respective nonequilibrium steady states as well as the full real-time evolution on unprecedented system sizes. Characteristic time scales are derived analytically, which allows us to understand the nontrivial finite-size scaling of the dissipative gap. The corresponding scaling exponents are confirmed by solving numerically for the full real-time evolution of two-point correlation functions.
description: 6 pages, 2 figures; version accepted for publication in PRA
Casimir Force in a Model with Strongly Adsorbing Competing Walls: Analytical Results
Creators: name: Dantchev, Daniel
name: Vassilev, Vassil
name: Djondjorov, Peter
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We present both analytical and numerical results for the behaviour of the Casimir force in a Ginzburg-Landau type model of a film of a simple fluid or binary liquid mixture in which the confining surfaces are strongly adsorbing but preferring different phases of the simple fluid, or different components of the mixture. Under such boundary conditions an interface is formed between the competing phases inside the system which are forced to coexist. We investigate the force as a function of the temperature and in the presence of an external ordering field and determine the (temperature-field) relief map of the force. We prove the existence of a single global maximum of the force and find its position and value. We find the asymptotic behavior of the force when any of the scaling fields becomes large while the other one is negligible. Contrary to the case of symmetric boundary conditions we find, as expected, that the finite system does not possess a phase transition of its own for any finite values of the scaling variables corresponding to the temperature and the ordering field. We perform the study near the bulk critical temperature of the corresponding bulk system and find a perfect agreement with the finite-size scaling theory.
description: 19 pages, 5 figures; two references and the text needed to incorporate them added, one reference updated
The ideal relativistic fluid limit for a medium with polarization
Creators: name: Montenegro, David
name: Tinti, Leonardo
name: Torrieri, Giorgio
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We use Lagrangian effective field theory techniques to construct the equations of motion for an ideal relativistic fluid whose constituent degrees of freedom have microscopic polarization. We discuss the meaning of such a system, and argue that it is the first term in the EFT appropriate for describing polarization observables in heavy ion collisions, such as final state particle polarization and chiral magnetic and vortaic effects. We show that this system will generally require non-dissipative dynamics at higher order in gradient than second order, leading to potential stability issues known with such systems. We comment on the significance of this in the light of conjectured lower limits on viscosity.
description: Version accepted for publication in Phys.Rev.D Discussion extended and clarified, conclusions and main ideas unchanged
Quantum correlations in composite systems
Creators: name: Sperling, J.
name: Agudelo, E.
name: Walmsley, I. A.
name: Vogel, W.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study emerging notions of quantum correlations in compound systems. Based on different definitions of quantumness in individual subsystems, we investigate how they extend to the joint description of a composite system. Especially, we study the bipartite case and the connection of two typically applied and distinctively different concepts of nonclassicality in quantum optics and quantum information. Our investigation includes the representation of correlated states in terms of quasiprobability matrices, a comparative study of joint and conditional quantum correlations, and an entanglement characterization. It is, for example, shown that our composition approach always includes entanglement as one form of quantum correlations. Yet, other forms of quantum correlations can also occur without entanglement. Finally, we give an outlook towards multimode systems and temporal correlations.
Hyperfiniteness of boundary actions of cubulated hyperbolic groups
Creators: name: Huang, Jingyin
name: Sabok, Marcin
name: Shinko, Forte
Publisher: name: arXiv
Year: 2017
Subjects: subject: Group Theory (math.GR)
subject: Logic (math.LO)
subject: FOS: Mathematics
subject: 03E15, 20F65

description: We show that if a hyperbolic group acts geometrically on a CAT(0) cube complex, then the induced boundary action is hyperfinite. This means that for a cubulated hyperbolic group the natural action on its Gromov boundary is hyperfinite, which generalizes an old result of Dougherty, Jackson and Kechris for the free group case.
description: updated questions
Soliton solutions for the elastic metric on spaces of curves
Creators: name: Bauer, Martin
name: Bruveris, Martins
name: Harms, Philipp
name: Michor, Peter
Publisher: name: arXiv
Year: 2017
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 58E10 (Primary) 49M25, 58B20, 58D10 (Secondary)

description: In this article we investigate a first order reparametrization-invariant Sobolev metric on the space of immersed curves. Motivated by applications in shape analysis where discretizations of this infinite-dimensional space are needed, we extend this metric to the space of Lipschitz curves, establish the wellposedness of the geodesic equation thereon, and show that the space of piecewise linear curves is a totally geodesic submanifold. Thus, piecewise linear curves are natural finite elements for the discretization of the geodesic equation. Interestingly, geodesics in this space can be seen as soliton solutions of the geodesic equation, which were not known to exist for reparametrization-invariant Sobolev metrics on spaces of curves.
description: Minor corrections; 27 pages, 4 figures, 3 movies
Generalized fermion symmetry, its currents algebra and Ward-Takahashi identities
Creators: name: Fariborz, Amir H.
name: Jora, Renata
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We introduce a new local symmetry into the fermion sector of a gauge invariant Lagrangian which may or may not contain a scalar or spontaneous symmetry breaking. The Standard Model in the unitary gauge and QCD are particular cases where this symmetry may apply. We determine the associated vector and axial vector currents and their conservation laws. We show that a single current conservation law may lead to multiple Ward-Takahashi identities. Our results can potentially have important consequences for effective models of low-energy QCD and hadron structure. As an specific example, we discuss the construction of tetraquark states within a generalized linear sigma model and show that this new symmetry probes the tetraquarks in a manner that is consistent with the large $N_c$ limit of QCD.
description: 10 pages, version published in Phys. Rev. D
Magnetically Advected Winds
Creators: name: Contopoulos, Ioannis
name: Kazanas, Demosthenes
name: Fukumura, Keigo
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Observations of X-ray absorption lines in magnetically driven disk winds around black hole binaries and active galactic nuclei yield a universal radial density profile rho proportional to r^{-1.2} in the wind. This is in disagreement with the standard Blandford & Payne profile rho_BP proportional to r^{-1.5} expected when the magnetic field is neither advected nor diffusing through the accretion disk. In order to account for this discrepancy, we establish a new paradigm for magnetically driven astrophysical winds according to which the large scale ordered magnetic field that threads the disk is continuously generated by the Cosmic Battery around the inner edge of the disk and continuously diffuses outward. We obtain self-similar solutions of such magnetically advected winds (MAW) and discuss their observational ramifications.
description: 5 pages, 1 figures, accepted for publication in Monthly Notices Letters
A contour for the entanglement entropies in harmonic lattices
Creators: name: Coser, Andrea
name: De Nobili, Cristiano
name: Tonni, Erik
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We construct a contour function for the entanglement entropies in generic harmonic lattices. In one spatial dimension, numerical analysis are performed by considering harmonic chains with either periodic or Dirichlet boundary conditions. In the massless regime and for some configurations where the subsystem is a single interval, the numerical results for the contour function are compared to the inverse of the local weight function which multiplies the energy-momentum tensor in the corresponding entanglement hamiltonian, found through conformal field theory methods, and a good agreement is observed. A numerical analysis of the contour function for the entanglement entropy is performed also in a massless harmonic chain for a subsystem made by two disjoint intervals.
description: 49 pages, 15 figures. v2: minor improvements, a figure added, published version
Growing length scale accompanying the vitrification: A perspective based on non-singular density fluctuations
Creators: name: Furukawa, Akira
Publisher: name: arXiv
Year: 2017
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: In glass forming liquids close to the glass transition point, even a very slight increase in the macroscopic density results in a dramatic slowing down of the macroscopic relaxation. Concomitantly, the local density itself fluctuates in space. Therefore, one can imagine that even very small local density variations control the local glassy nature. Based on this perspective, a model for describing growing length scale accompanying the vitrification is introduced, in which we assume that in a subsystem whose density is above a certain threshold value, $ρ_{\rm c}$, owing to steric constraints, particle rearrangements are highly suppressed for a sufficiently long time period ($\sim$ structural relaxation time). We regard such a subsystem as a glassy cluster. Then, based on the statistics of the subsystem-density, we predict that with compression (increasing average density $ρ$) at a fixed temperature $T$ in supercooled states, the characteristic length of the clusters, $ξ$, diverges as $ξ\sim(ρ_{\rm c}-ρ)^{-2/d}$, where $d$ is the spatial dimensionality. This $ξ$ measures the average persistence length of the steric constraints in blocking the rearrangement motions and is determined by the subsystem density. Additionally, with decreasing $T$ at a fixed $ρ$, the length scale diverges in the same manner as $ξ\sim(T-T_{\rm c})^{-2/d}$, for which $ρ$ is identical to $ρ_{\rm c}$ at $T=T_{\rm c}$. The exponent describing the diverging length scale is the same as the one predicted by some theoretical models and indeed has been observed in some simulations and experiments. However, the basic mechanism for this divergence is different; that is, we do not invoke thermodynamic anomalies associated with the thermodynamic phase transition as the origin of the growing length scale. We further present arguements for the cooperative properties based on the clusters.
description: 10 pages, 7 figures
Effective Target Aware Visual Navigation for UAVs
Creators: name: Potena, Ciro
name: Nardi, Daniele
name: Pretto, Alberto
Publisher: name: arXiv
Year: 2017
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: In this paper we propose an effective vision-based navigation method that allows a multirotor vehicle to simultaneously reach a desired goal pose in the environment while constantly facing a target object or landmark. Standard techniques such as Position-Based Visual Servoing (PBVS) and Image-Based Visual Servoing (IBVS) in some cases (e.g., while the multirotor is performing fast maneuvers) do not allow to constantly maintain the line of sight with a target of interest. Instead, we compute the optimal trajectory by solving a non-linear optimization problem that minimizes the target re-projection error while meeting the UAV's dynamic constraints. The desired trajectory is then tracked by means of a real-time Non-linear Model Predictive Controller (NMPC): this implicitly allows the multirotor to satisfy both the required constraints. We successfully evaluate the proposed approach in many real and simulated experiments, making an exhaustive comparison with a standard approach.
description: Conference paper at "European Conference on Mobile Robotics" (ECMR) 2017
British Gallup Poll CQ 339
Creators: name: Social Surveys (Gallup Poll) Limited
Publisher: name: Roper Center for Public Opinion Research
Year: 2022

description: Government approval (1); James Callaghan performance (1); Margaret Thatcher performance (1); Daniel Steel performance (1); party support (1); last general election (2); urgent problems (2); best party to handle problems (1); next general election (2); party with best policies (1); party with best leaders (1); party unity (2); difference in parties (1); best Prime Minister (1); government price policy (11); energy shortage (4); nationalizing industries and oil (8); oil companies (11); building societies (42); sewing machine (4); kitchen furniture (48); bedroom furniture (41); living room furniture (5); Mothercare (1); perfume (26); bread mixes (17).
Parton saturation scaling function for exclusive production of vector mesons and Deeply Virtual Compton Scattering
Creators: name: Ben, F. G.
name: Machado, M. V. T.
name: Sauter, W. K.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We provide a universal expression of cross sections for the exclusive vector meson production and Deeply Virtual Compton Scattering (DVCS) in photon-proton and photon-nucleus interactions based on the geometric scaling phenomenon. The theoretical parameterization based on the scaling property depends only on the single variable $τ_A = Q^2/Q_{\mathrm{sat}}^2$, where the saturation scale, $Q_{\mathrm{sat}}$, drives the energy dependence and the corresponding nuclear effects. This phenomenological result describes all available data from DESY-HERA for $ρ,\,ϕ,\,J/ψ$ production and DVCS measurements. A discussion on the size of nuclear shadowing corrections on photon-nucleus interaction is also done.
description: 8 pages, 3 figures and 2 tables. Extended version to be published in Physical Review D. Title has been changed
title: Critical mineral resources related to the rise and fall of a supercontinent
Creators: name: Burisch, Mathias
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:

The European Variscides host significant resources of energy and technology critical raw materials (ETRs) associated to various types of hydrothermal systems. Hydrothermal mineralization in central and western Europe is mainly related to the i) amalgamation and ii) the breakup of the supercontinent Pangea during the Late-Paleozoic and Mesozoic, respectively. These mega tectonic events also facilitated the formation of mineral deposits in northern Africa and eastern North America. Late-Paleozoic magmatic-hydrothermal activity was associated with the formation of greisen, skarn and epithermal vein systems that host valuable Li, Sn, W, Ag, Zn, Sb Cu and In. Conversely, Mesozoic rift-related hydrothermal activity resulted in the formation of unconformity-related vein type mineralization, which host significant resources of Co, Ni, Bi, Ag, Zn and fluorite.

This talk provides a brief overview on the different deposit types and associated ETRs in central Europe and discusses ore-forming mechanisms in two distinctly different geological environments (orogenic vs. rift-related). After discussing ore-forming mechanisms on the deposit scale, the findings are complemented by a large amount of recent geochronological data (mainly in-situ LA-ICP-MS U-Pb) that constrain the age of individual ore deposits and mineral occurrences in the context of the larger tectonic framework of central Europe. These results are integrated into preliminary continental-scale geological models for Late-Paleozoic and Mesozoic hydrothermal systems in central and western Europe. The preliminary models convincingly demonstrate that individual ore deposits are local expressions of geological processes that occur on a mega tectonic scale – driven by the rise and fall of the supercontinent Pangea.  
Approximating quantum many-body wave-functions using artificial neural networks
Creators: name: Cai, Zi
name: Liu, Jinguo
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In this paper, we demonstrate the expressibility of artificial neural networks (ANNs) in quantum many-body physics by showing that a feed-forward neural network with a small number of hidden layers can be trained to approximate with high precision the ground states of some notable quantum many-body systems. We consider the one-dimensional free bosons and fermions, spinless fermions on a square lattice away from half-filling, as well as frustrated quantum magnetism with a rapidly oscillating ground-state characteristic function. In the latter case, an ANN with a standard architecture fails, while that with a slightly modified one successfully learns the frustration-induced complex sign rule in the ground state and approximates the ground states with high precisions. As an example of practical use of our method, we also perform the variational method to explore the ground state of an anti-ferromagnetic $J_1-J_2$ Heisenberg model.
description: variational results of J1-J2 model have been added
Fast and slow thermal processes in harmonic scalar lattices
Creators: name: Kuzkin, Vitaly A.
name: Krivtsov, Anton M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Classical Physics (physics.class-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: An approach for analytical description of thermal processes in harmonic lattices is presented. We cover longitudinal and transverse vibrations of chains and out-of-plane vibrations of two-dimensional lattices with interactions of an arbitrary number of neighbors. Motion of each particle is governed by a single scalar equation and therefore the notion "scalar lattice" is used. Evolution of initial temperature field in an infinite lattice is investigated. An exact equation describing the evolution is derived. Continualization of this equation with respect to spatial coordinates is carried out. The resulting continuum equation is solved analytically. The solution shows that the kinetic temperature is represented as the sum of two terms, one describing short time behavior, the other large time behavior. At short times, the temperature performs high-frequency oscillations caused by redistribution of energy among kinetic and potential forms (fast process). Characteristic time of this process is of order of ten periods of atomic vibrations. At large times, changes of the temperature are caused by ballistic heat transfer (slow process). The temperature field is represented as a superposition of waves having the shape of initial temperature distribution and propagating with group velocities dependent on the wave vector. Expressions describing fast and slow processes are invariant with respect to substitution $t$ by $-t$. However examples considered in the paper demonstrate that these processes are irreversible. Numerical simulations show that presented theory describes the evolution of temperature field at short and large time scales with high accuracy.
description: 26 pages, 7 figures
Prospects for Measuring Cosmic Microwave Background Spectral Distortions in the Presence of Foregrounds
Creators: name: Abitbol, Maximilian H.
name: Chluba, Jens
name: Hill, J. Colin
name: Johnson, Bradley R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Measurements of cosmic microwave background spectral distortions have profound implications for our understanding of physical processes taking place over a vast window in cosmological history. Foreground contamination is unavoidable in such measurements and detailed signal-foreground separation will be necessary to extract cosmological science. We present MCMC-based spectral distortion detection forecasts in the presence of Galactic and extragalactic foregrounds for a range of possible experimental configurations, focusing on the Primordial Inflation Explorer (PIXIE) as a fiducial concept. We consider modifications to the baseline PIXIE mission (operating 12 months in distortion mode), searching for optimal configurations using a Fisher approach. Using only spectral information, we forecast an extended PIXIE mission to detect the expected average non-relativistic and relativistic thermal Sunyaev-Zeldovich distortions at high significance (194$σ$ and 11$σ$, respectively), even in the presence of foregrounds. The $Λ$CDM Silk damping $μ$-type distortion is not detected without additional modifications of the instrument or external data. Galactic synchrotron radiation is the most problematic source of contamination in this respect, an issue that could be mitigated by combining PIXIE data with future ground-based observations at low frequencies ($ν< 15-30$GHz). Assuming moderate external information on the synchrotron spectrum, we project an upper limit of $|μ| < 3.6\times 10^{-7}$ (95\% c.l.), slightly more than one order of magnitude above the fiducial $Λ$CDM signal from the damping of small-scale primordial fluctuations, but a factor of $\simeq 250$ improvement over the current upper limit from COBE/FIRAS. This limit could be further reduced to $|μ| < 9.4\times 10^{-8}$ (95\% c.l.) with more optimistic assumptions about low-frequency information. (Abridged)
description: (16 pages, 11 figures, submitted to MNRAS. Fisher code available at https://github.com/mabitbol/sd_foregrounds. Updated with published version.)
Magnetized strange quark model with Big Rip singularity in $f(R,T)$ gravity
Creators: name: Sahoo, P. K.
name: Sahoo, Parbati
name: Bishi, Binaya K.
name: Aygün, S.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences
subject: 83F05, 83C15

description: LRS (Locally Rotationally symmetric) Bianchi type-I magnetized strange quark matter cosmological model have been studied based on $f(R,T)$ gravity. The exact solutions of the field equations are derived with linearly time varying deceleration parameter which is consistent with observational data (from SNIa, BAO and CMB) of standard cosmology. It is observed that the model start with big bang and ends with a Big Rip. The transition of deceleration parameter from decelerating phase to accelerating phase with respect to redshift obtained in our model fits with the recent observational data obtained by Farook et al. in 2017. The well known Hubble parameter $H(z)$ and distance modulus $μ(z)$ are discussed with redshift.
description: Accepted for publication in MPLA
Magnetic field instability driven by anomalous magnetic moments of massive fermions and electroweak interaction with background matter
Creators: name: Dvornikov, Maxim
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: It is shown that the electric current of massive fermions along the external magnetic field can be excited in the case when particles possess anomalous magnetic moments and electroweakly interact with background matter. This current is calculated on the basis of the exact solution of the Dirac equation in the external fields. It is shown that the magnetic field becomes unstable if this current is taken into account in the Maxwell equations. Considering a particular case of a degenerate electron gas, which can be found in a neutron star, it is revealed that the seed magnetic field can be significantly enhanced. The application of the results to astrophysics is also discussed.
description: 9 pages in LaTeX2e, 2 eps figures; paper is significantly revised, the comparison with the chiral magnetic effect is added; version to be published in JETP Letters
Vertical Landing for Micro Air Vehicles using Event-Based Optical Flow
Creators: name: Hordijk, Bas J. Pijnacker
name: Scheper, Kirk Y. W.
name: de Croon, Guido C. H. E.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Small flying robots can perform landing maneuvers using bio-inspired optical flow by maintaining a constant divergence. However, optical flow is typically estimated from frame sequences recorded by standard miniature cameras. This requires processing full images on-board, limiting the update rate of divergence measurements, and thus the speed of the control loop and the robot. Event-based cameras overcome these limitations by only measuring pixel-level brightness changes at microsecond temporal accuracy, hence providing an efficient mechanism for optical flow estimation. This paper presents, to the best of our knowledge, the first work integrating event-based optical flow estimation into the control loop of a flying robot. We extend an existing 'local plane fitting' algorithm to obtain an improved and more computationally efficient optical flow estimation method, valid for a wide range of optical flow velocities. This method is validated for real event sequences. In addition, a method for estimating the divergence from event-based optical flow is introduced, which accounts for the aperture problem. The developed algorithms are implemented in a constant divergence landing controller on-board of a quadrotor. Experiments show that, using event-based optical flow, accurate divergence estimates can be obtained over a wide range of speeds. This enables the quadrotor to perform very fast landing maneuvers.
description: 29 pages, 14 figures, under peer review
title: Applied mineralogy for sustainable use of materials
Creators: name: Weidenthaler, Claudia
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
Adapting nature offers a wide variety of opportunities to create advanced materials in the laboratory that find their templates in natural minerals. Materials, which are nowadays gaining increasing importance, are mainly those related to economically, environmentally and socially sustainable processes. Minerals and their synthetic counterparts are used, for instance, for purification processes, energy conversion and storage materials, or as bio-inspired materials with structures and properties mimicking those of natural materials.

One example of a success story in which minerals provide the original for synthetic materials used on a large scale is zeolites. Natural zeolites, microporous aluminosilicates, are mostly formed in volcanic rocks by a hydrothermal transformation of e.g. volcanic ashes at low temperatures and almost without pressure. The formation conditions may sound relatively simple but the reconstruction of synthetic zeolite analogues is much more complex than might have been expected at first. The fascinating crystal structures with different channel and pore architectures have opened a wide field of technical applications. Both natural and synthetic representatives are used on a large scale in industry and agriculture. Zeolites are utilized as absorbers for water purification, gas-cleaning processes and catalysis. For the understanding of their physical and chemical properties, detailed information about formation conditions and crystal structures is essential.

The profound knowledge of minerals, their synthesis, crystal chemistry and characterization methods makes applied mineralogy and crystallography indispensable disciplines in the development of new and exciting materials for sustainable processes.
Exact dynamics following an interaction quench in a one-dimensional anyonic gas
Creators: name: Piroli, Lorenzo
name: Calabrese, Pasquale
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the nonequilibrium quench dynamics of a one-dimensional anyonic gas. We focus on the integrable anyonic Lieb-Liniger model and consider the quench from non-interacting to hard-core anyons. We study the dynamics of the local properties of the system. By means of integrability-based methods we compute analytically the one-body density matrix and the density-density correlation function at all times after the quench and in particular at infinite time. Our results show that the system evolves from an initial state where the local momentum distribution function is non-symmetric to a steady state where it becomes symmetric. Furthermore, while the initial momentum distribution functions (and the equilibrium ones) explicitly depend on the anyonic parameter, the final ones do not. This is reminiscent of the dynamical fermionization observed in the context of free expansions after release from a confining trap.
description: 24 pages, 7 figures; v2: minor revision and references added
Defects in the Tri-critical Ising model
Creators: name: Makabe, Isao
name: Watts, Gerard M T
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider two different conformal field theories with central charge c=7/10. One is the diagonal invariant minimal model in which all fields have integer spins; the other is the local fermionic theory with superconformal symmetry in which fields can have half-integer spin. We construct new conformal (but not topological or factorised) defects in the minimal model. We do this by first constructing defects in the fermionic model as boundary conditions in a fermionic theory of central charge c=7/5, using the folding trick as first proposed by Gang and Yamaguchi. We then acting on these with interface defects to find the new conformal defects. As part of the construction, we find the topological defects in the fermionic theory and the interfaces between the fermionic theory and the minimal model. We also consider the simpler case of defects in the theory of a single free fermion and interface defects between the Ising model and a single fermion as a prelude to calculations in the tri-critical Ising model.
description: 54 pages, 5 figures, version as accepted for publication with minor changes
Gravity stabilizes itself
Creators: name: Chakraborty, Sumanta
name: SenGupta, Soumitra
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We show that a possible resolution to the stabilization of an extra spatial dimension (radion) can be obtained solely in the context of gravitational dynamics itself without the necessity of introducing any external stabilizing field. In this scenario the stabilized value of the radion field gets determined in terms of the parameters appearing in the higher curvature gravitational action. Furthermore, the mass of the radion field and its coupling to the standard model fields are found to be in the weak scale implying possible signatures in the TeV scale colliders. Some resulting implications are also discussed.
description: Revised Version, 19 pages, no figures
Quantum simulation of quantum channels in nuclear magnetic resonance
Creators: name: Xin, Tao
name: Wei, Shi-Jie
name: Pedernales, Julen S.
name: Solano, Enrique
name: Long, Gui-Lu
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose and experimentally demonstrate an efficient framework for the quantum simulation of quantum channels in NMR. Our approach relies on the suitable decomposition of non-unitary operators in a linear combination of $d$ unitary ones, which can be then experimentally implemented with the assistance of a number of ancillary qubits that grows logarithmically in $d$. As a proof-of-principle demonstration, we realize the quantum simulation of three quantum channels for a single-qubit: phase damping (PD), amplitude damping (AD), and depolarizing (DEP) channels. For these paradigmatic cases, we measure key features, such as the fidelity of the initial state and the associated von Neuman entropy for a qubit evolving through these channels. Our experiments are carried out using nuclear spins in a liquid sample and NMR control techniques.
description: 8 pages, 7 figures, All comments are welcome
Scaling law of high harmonic generation in the framework of photon channel
Creators: name: Li, Liang
name: Lan, Pengfei
name: He, Lixin
name: Zhu, Xiaosong
name: Chen, Jing
name: Lu, Peixiang
Publisher: name: arXiv
Year: 2017
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Photon channel perspective on high harmonic generation (HHG) is proposed by quantizing both the driving laser and high harmonics. It is shown that the HHG yield can be expressed as a sum of the contribution of all the photon channels. From this perspective, the contribution of a specific photon channel follows a simple scaling law and the competition between the channels is well interpreted. Our prediction is shown to be in good agreement with the simulations by solving the time-dependent Schrodinger equation. It also can well explains the experimental results of the HHG in the noncollinear two-color field and bicicular laser field.
title: Green in grey: ecosystem services and disservices perceptions from small-scale green infrastructure along a rural-urban gradient in Bengaluru, India
Creators: name: Thapa, Pramila
name: Torralba, Mario
name: Bhaskar, Dhanya
name: Nagendra, Harini
name: Plieninger, Tobias
Publisher: name: Universität Kassel
Year: 2023
Subjects: subject: multifunctionality
subject: photoelicitation
subject: socio-economic preferences
subject: trees
subject: urbanization
subject: 570
subject: Bangalore
subject: Indien
subject: Urbanität
subject: Photoanregung
subject: Baum
subject: Multifunktionalität

description: Gefördert durch den Publikationsfonds der Universität Kassel
Uncertainty quantification in the dynamic analysis of offshore structures
Creators: name: Lim, HyeongUk
name: 0000-0003-1262-0517
Publisher: name: The University of Texas at Austin
Year: 2019
Subjects: Uncertainty quantification
Structural dynamics
Surrogate modeling
Dimension reduction
Offshore structures

description: Consideration for uncertainty is critical in problems associated with structural dynamics, especially in the offshore environment. Deterministic solutions are often insufficient to achieve confidence in computational results and for use in design. In uncertainty quantification (UQ) for problems dealing with many random or stochastic sources, surrogate models are often developed to reduce costs associated with running a "truth" model to verify response levels associated with low probability. Polynomial chaos expansion (PCE) is one approach used in developing such surrogate models. However, conventional PCE relies on parametric families to define the polynomials for expansion. Also, for high-dimensional problems, PCE can be inefficient if appropriate dimension reduction is not employed. Arbitrary PCE (aPCE) approaches, based on Gram-Schmidt orthogonalization, can be used to define polynomials in terms of the uncertain variables and offers a non-parametric option for UQ. An aPCE approach that can systematically account for multivariate stochasticity is developed in this study. Dimension reduction can aid in developing computationally efficient surrogate models; in this study, a gradient-based active subspace approach that identifies dominant influences on a model output's variability is employed for dimension reduction. Both aPCE and active-subspace dimension reduction are employed in studies that are focused on the dynamics of offshore structures and on low-probability events of interest. This dissertation represents a collection of four papers that deal with PCE surrogate modeling and dimension reduction. Each paper, representing a separate chapter, contributes to the development of accurate and efficient UQ approaches for offshore structure dynamics problems involving various sources of uncertainty. We demonstrate the proposed approaches in different applications: I. estimation of fatigue damage in a marine riser due to vortex-induced vibration; II. prediction of the long-term extreme response of a moored floating structure; III. surrogate model development for structural reliability analysis; and IV. dimension reduction in the extreme response prediction of offshore structures.
Positivity of LCK potential
Creators: name: Ornea, Liviu
name: Verbitsky, Misha
Publisher: name: arXiv
Year: 2017
Subjects: subject: Differential Geometry (math.DG)
subject: Complex Variables (math.CV)
subject: FOS: Mathematics

description: Let $M$ be a complex manifold and $L$ an oriented real line bundle on M equipped with a flat connection. An LCK ("locally conformally Kahler") form is a closed, positive (1,1)-form taking values in L, and an LCK manifold is one which admits an LCK form. Locally, any LCK form is expressed as an L-valued pluri-Laplacian of a function called LCK potential. We consider a manifold $M$ with an LCK form admitting a global LCK potential, and prove that M admits a global, positive LCK potential. Then M admits a holomorphic embedding to a Hopf manifold.
description: 14 pages, version 2.0. Several proofs simplified