cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Small prey for small cats: the importance of prey-size in the diet of southern tiger cat Leopardus guttulus in a competitor-free environment
Creators: name: Tortato, Marcos Adriano
name: Oliveira-Santos, Luiz Gustavo Rodrigues
name: Moura, Maurício Osvaldo
name: de Oliveira, Tadeu Gomes
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology

description: Small cats can have a direct influence on the organization of small Neotropical vertebrate communities. However, the magnitude of influence and role(s) played by small felids, including Leopardus guttulus, in regulating prey populations is not well understood. This study aims to determine if there is a key-taxon in the dietary composition of the southern tiger (S-tiger) cat and evaluate the relationship between prey availability and use in the restinga habitat of Southern Brazil. Oligoryzomys spp. were identified as one of the main prey items and found to be among the highest density mammal species in the restinga habitat. However, as Oligoryzomys spp. were not among the preferred prey species in the S-tiger cat’s diet, the high frequency of predation is probably a consequence of their high abundance. The diet of the S-tiger cat is characteristic of a generalist predator, eating a high diversity of different prey species, consumed per their availability, and selected according to mass and accessibility. However, in this area devoid of other felid competitors and with abundant prey, S-tiger cat seems to consume prey species within a relatively narrow mass spectrum (6–25 g), although it does not appear to select any specific taxon of any class size.
Saul : Oratorium
Creators: name: Händel, Georg Friedrich
Publisher: name: Hofmeister
Year: 1821

description: von G.F. Händel ; mit untergelegtem deutschen Text von C.D.E. ; im vollst. Klavierauszug von J.F. Naue
description: Ite und IIte Abtheilung in einem Band zusammengebunden. IIte Abtheilung bestehend aus: Zweiter Theil (S. 1-59), Dritter Theil (S. 60-109)
description: Text: deutsch ; HWV 53
description: Originalbesetzung: Singstimme (mehrere), Chor, Orchester
Orbital entanglement and electron localization in quantum wires
Creators: name: Aleta, Alberto
name: Villarubia-Rojo, Héctor
name: Frustaglia, Diego
name: Gopar, Víctor A.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the signatures of disorder in the production of orbital electron entanglement in quantum wires. Disordered entanglers suffer the effects of localization of the electron wave function and random fluctuations in the entanglement production. This manifests in the statistics of the concurrence, a measure of the produced two-qubit entanglement. We calculate the concurrence distribution as a function of the disorder strength within a random-matrix approach. We also identify significant constraints on the entanglement production as a consequence of the breaking/preservation of time-reversal invariance. Additionally, our theoretical results are independently supported by simulations of disordered quantum wires based on a tight-binding model.
description: 6 pages, 4 figures. Minor changes
title: (Digitale) Präsenz in der Lehre
Creators: name: Bachmeier, Regine
Publisher: name: Zentrum für Hochschul- und Wissenschaftsdidaktik, Universität Regensburg
Year: 2021

description: Im Podcast spricht Dr. Marija Stanisavljevic über den Stellenwert und die Funktionen von Präsenz in realen und virtuellen Lehrveranstaltungen.
Ravines as conservation strongholds for small wildcats under pressure from free-ranging dogs and cats in Mediterranean landscapes of Chile
Creators: name: Beltrami, Esperanza
name: Gálvez, Nicolás
name: Osorio, Christian
name: Kelly, Marcella J.
name: Morales-Moraga, David
name: Bonacic, Cristian
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Neuroscience
subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology
subject: 69999 Biological Sciences not elsewhere classified
subject: Inorganic Chemistry
subject: FOS: Chemical sciences

description: The Chilean Mediterranean ecosystem is threatened by anthropogenic pressures, such as habitat loss by intensive agriculture and urban sprawl. Abandoned dogs (Canis lupus familiaris) and cats (Felis silvestris catus) pose conservation challenges for Chilean wildlife including the pampas cat (Leopardus colocolo) and the güiña (Leopardus guigna). We used camera trap data to investigate influences of natural and anthropogenic landscape features on spatiotemporal trends of these species. We also used co-occurrence modeling and kernel density estimation to investigate spatial and temporal patterns overlap of wildcats, free-ranging (FR) dogs, and FR-cats. FR-dogs showed the highest detection and site use probabilities, while güiñas had the lowest across 80 camera trap sites. Top models showed no spatial avoidance between species and co-occurrence of wildcats was positively influenced by forest habitat. However, FR-dogs negatively affected detection of wildcats. Ravines surrounded by forest positively influenced güiña and pampas cat detection probabilities when dominant species were not present. FR-dogs and wildcats had significantly different temporal activity patterns and low overlap coefficients, while wildcats and FR-cats showed high overlap in activity patterns. We suggest changing current policies to control domestic animals and strategic planning in agricultural areas of central Chile to better conserve native wildcat species.
Evidence for non-Markovian electron dynamics in the microwave absorption of a two-dimensional electron system
Creators: name: Dorozhkin, S. I.
name: Kapustin, A. A.
name: Dmitriev, I. A.
name: Umansky, V.
name: von Klitzing, K.
name: Smet, J. H.
Publisher: name: Universität Regensburg
Year: 2017
Subjects: subject: CYCLOTRON-RESONANCE; MAGNETIC-FIELD; ANTIDOT ARRAYS; LORENTZ MODEL; MAGNETOTRANSPORT; LOCALIZATION; MAGNETORESISTANCE; GAS;
subject: 530 Physik

description: We have studied the absorption of monochromatic microwave radiation in high-quality two-dimensional electron systems for the frequency span from 10 to 380 GHz using a bolometric method. For frequencies above 100 GHz the absorption exhibits an anomalous magnetic field dependence. Minima form at harmonics of the cyclotron resonance frequency. The results contrast previously reported data for other frequency ranges. Quasiclassical memory effects originating from the non-Markovian dynamics of electrons in a disorder potential containing short-range scatterers on top of a smooth potential background favorably account for the observed behavior.
D3.1 Tools and techniques for the management of trustworthy evidence-v1
Creators: name: Regueiro, Cristina
Publisher: name: Zenodo
Year: 2022
Subjects: Evidence gathering tools
Trustworthiness
Blockchain
EUCS

description: This deliverable will encompass techniques how to integrate different tools to gather and manage trustworthy evidence on various levels as well as how to ensure the trustworthiness of evidence across the life-cycle, i.e. using blockchain/DLT. There will be three iterations of the deliverable, an initial prototype, reflecting an early stage of integration in the technical framework (D3.1.x), the second release will be based on a refinement of the technical architecture, finally the third iteration will reflect the implementation of the use cases. This deliverable is the result of Task 3.1 and Task 3.5.
Cryptic diversity in a neotropical avian species complex untangled by neglected genetic evidence
Creators: name: Forcina, Giovanni
name: Boesman, Peter
name: Jowers, Michael J.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Genetics
subject: FOS: Biological sciences
subject: Evolutionary Biology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology
subject: 69999 Biological Sciences not elsewhere classified
subject: Plant Biology

description: Over the last two decades, vocal and genetic data have been extensively used in avian studies addressing taxonomic and systematic issues. However, even when multiple lines of evidence lean toward lumping or splitting of species, some taxonomic committees refuse to acknowledge their validity until convincing genetic evidence is produced and integrated with other sources of data. As a case in point, the genus Pseudocolaptes (Furnariidae) consists of three mostly allopatric and overtly distinct neotropical taxa differing in plumage and vocal features: the Streaked Tuftedcheek (P. boissonneautii), the Buffy Tuftedcheek (P. lawrencii), and the contentious Pacific Tuftedcheek (P. johnsoni). In this study, we assemble already available mitochondrial and nuclear DNA sequences to assess their taxonomy and to provide appointed committees with specific proof to ascertain the number of Pseudocolaptes species. Phylogenetic inference and species delimitation analysis indicate three species equally divergent from each other. We hope that this work will contribute to resolve the long-lasting taxonomical confusion regarding this genus, and that proper future conservation plans will be adopted to preserve each species within the inhabited biodiversity hotspot.
Excluding the Light Dark Matter Window of a 331 Model Using LHC and Direct Dark Matter Detection Data
Creators: name: Cogollo, D.
name: Gonzalez-Morales, Alma X.
name: Queiroz, Farinaldo S.
name: Teles, Patricia Rebello
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We sift the impact of the recent Higgs precise measurements, and recent dark matter direct detection results, on the dark sector of an electroweak extension of the Standard Model that has a complex scalar as dark matter. We find that in this model the Higgs decays with a large branching ratio into dark matter particles, and charged scalars when these are kinematically available, for any coupling strength differently from the so called Higgs portal. Moreover, we compute the abundance and spin-independent WIMP-nucleon scattering cross section, which are driven by the Higgs and $Z^{\prime}$ boson processes. We decisively exclude the $1-500$~GeV dark matter window and find the most stringent lower bound in the literature on the scale of symmetry breaking of the model namely $10$~TeV, after applying the LUX-2013 limit. Interestingly, the projected XENON1T constraint will be able to rule out the entire $1$~GeV-$1000$~GeV dark matter mass range. Lastly, for completeness, we compute the charged scalar production cross section at the LHC and comment on the possibility of detection at current and future LHC runnings.
description: 11 pages, 7 figures
Nonperturbative comparison of clover and highly improved staggered quarks in lattice QCD and the properties of the ϕ meson
Creators: name: Chakraborty, Bipasha
name: Davies, C. T. H.
name: Donald, G. C.
name: Koponen, J.
name: Lepage, G. P.
Publisher: name: Universität Regensburg
Year: 2017
Subjects: subject: PERTURBATION-THEORY; RENORMALIZATION; FERMIONS;
subject: 530 Physik

description: We compare correlators for pseudoscalar and vector mesons made from valence strange quarks using the clover quark and highly improved staggered quark (HISQ) formalisms in full lattice QCD. We use fully nonperturbative methods to normalize vector and axial vector current operators made from HISQ quarks, clover quarks and from combining HISQ and clover fields. This allows us to test expectations for the renormalization factors based on perturbative QCD, with implications for the error budget of lattice QCD calculations of the matrix elements of clover-staggered b-light weak currents, as well as further HISQ calculations of the hadronic vacuum polarization. We also compare the approach to the (same) continuum limit in clover and HISQ formalisms for the mass and decay constant of the phi meson. Our final results for these parameters, using single-meson correlators and allowing an uncertainty for the neglect of quark-line disconnected diagrams are: M-phi = 1.023(6) GeV and f(phi) = 0.238(3) GeV in good agreement with experiment. The results come fromcalculations in the HISQformalism using gluon fields that include the effect of u, d, s and c quarks in the sea with three lattice spacing values and mu/d values going down to the physical point.
Wilson loops in N=6 superspace for ABJM theory
Creators: name: Rosso, Matteo
name: Vergu, Cristian
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we construct a light-like polygonal Wilson loop in N=6 superspace for ABJM theory. We then use it to obtain constraints on its two- and three-loop bosonic version, by focusing on higher order terms in the $θ$ expansion. The Grassmann expansion of the three-loop answer contains integrals which may be elliptic polylogarithms. Our results take their simplest form when expressed in terms of OSp(6|4) supertwistors.
description: 29 pages, added references, added comments about the relation with scattering amplitudes; version accepted for publication
Propagation of gravitational waves in the nonperturbative spinor vacuum
Creators: name: Dzhunushaliev, Vladimir
name: Folomeev, Vladimir
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The propagation of gravitational waves on the background of a nonperturbative vacuum of a spinor field is considered. It is shown that there are several distinctive features in comparison with the propagation of plane gravitational waves through empty space: there exists the fixed phase difference between the $h_{yy,zz}$ and $h_{yz}$ components of the wave; the phase and group velocities of gravitational waves are not equal to the velocity of light; the group velocity is always less than the velocity of light; under some conditions the gravitational waves are either damped or absent; for given frequency, there exist two waves with different wave vectors. We also discuss the possibility of experimental verification of the obtained effects as a tool to investigate nonperurbative quantum field theories.
description: some changes
Entanglement in N-harmonium: bosons and fermions
Creators: name: Benavides-Riveros, C. L.
name: Toranzo, I. V.
name: Dehesa, J. S.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The ground-state entanglement of a single particle of the N-harmonium system (i.e., a completely-integrable model of $N$ particles where both the confinement and the two-particle interaction are harmonic) is shown to be analytically determined in terms of $N$ and the relative interaction strength. For bosons, we compute the von Neumann entropy of the one-body reduced density matrix by using the corresponding natural occupation numbers. There exists a critical number $N_c$ of particles so that below it, for positive values of the coupling constant, the entanglement grows when the number of particles is increasing; the opposite occurs for $N > N_c$. For fermions, we compute the one-body reduced density matrix for the closed-shell spinned case. In the strong coupling regime, the linear entropy of the system decreases when $N$ is growing. For fixed $N$, the entanglement is found (a) to decrease (increase) for negatively (positively) increasing values of the coupling constant, and (b) to grow when the energy is increasing. Moreover, the spatial and spin contributions to the total entanglement are found to be of comparable size.
description: 27 pages, 9 figures, minor changes, 4 improved figures, references added, some typos corrected
title: Lightboard-Lehrvideos: Spotlight auf das Wesentliche
Creators: name: Bachmaier, Regine
Publisher: name: Zentrum für Hochschul- und Wissenschaftsdidaktik, Universität Regensburg
Year: 2021

description: Der Beitrag informiert über die Umsetzung einen tafelunterstützten Vortrag als asynchrones Lehrvideo mit Hilfe eines Lightboards sowie dem Mehrwert dieses Format
Proximity Effects in Bilayer Graphene on Monolayer WSe2 : Field-Effect Spin Valley Locking, Spin-Orbit Valve, and Spin Transistor
Creators: name: Gmitra, Martin
name: Fabian, Jaroslav
Publisher: name: Universität Regensburg
Year: 2017
Subjects: subject: DER-WAALS HETEROSTRUCTURES; HGTE QUANTUM-WELLS; TRANSITION; SURFACE; SPINTRONICS; METAL; SEMICONDUCTOR; DEVICES; BANDGAP; STATE;
subject: 530 Physik

description: Proximity orbital and spin-orbit effects of bilayer graphene on monolayer WSe2 are investigated from first principles. We find that the built-in electric field induces an orbital band gap of about 10 me V in bilayer graphene. Remarkably, the proximity spin-orbit splitting for holes is 2 orders of magnitude-the spin-orbit splitting of the valence band at K is about 2 meV-more than for electrons. Effectively, holes experience spin valley locking due to the strong proximity of the lower graphene layer to WSe2. However, applying an external transverse electric field of some 1 V/nm, countering the built-in field of the heterostructure, completely reverses this effect and allows, instead of holes, electrons to be spin valley locked with 2 meV spin-orbit splitting. Such a behavior constitutes a highly efficient field-effect spin-orbit valve, making bilayer graphene on WSe2 a potential platform for a field-effect spin transistor.
Consistent inference of a general model using the pseudo-likelihood method
Creators: name: Mozeika, Alexander
name: Dikmen, Onur
name: Piili, Joonas
Publisher: name: arXiv
Year: 2014
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Recently maximum pseudo-likelihood (MPL) inference method has been successfully applied to statistical physics models with intractable likelihoods. We use information theory to derive a relation between the pseudo-likelihood and likelihood functions. We use this relation to show consistency of the pseudo-likelihood method for a general model.
description: A new more mathematically rigorous version accepted for publication in Physical Review E: Rapid Communication
An optimal survey geometry of weak lensing survey: minimizing super-sample covariance
Creators: name: Takahashi, Ryuichi
name: Soma, Shunji
name: Takada, Masahiro
name: Kayo, Issha
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Upcoming wide-area weak lensing surveys are expensive both in time and cost and require an optimal survey design in order to attain maximum scientific returns from a fixed amount of available telescope time. The super-sample covariance (SSC), which arises from unobservable modes that are larger than the survey size, significantly degrades the statistical precision of weak lensing power spectrum measurement even for a wide-area survey. Using the 1000 mock realizations of the log-normal model, which approximates the weak lensing field for a $Λ$-dominated cold dark matter model, we study an optimal survey geometry to minimize the impact of SSC contamination. For a continuous survey geometry with a fixed survey area, a more elongated geometry such as a rectangular shape of 1:400 side-length ratio reduces the SSC effect and allows for a factor 2 improvement in the cumulative signal-to-noise ratio ($S/N$) of power spectrum measurement up to $\ell_{\rm max}\simeq $ a few $10^3$, compared to compact geometries such as squares or circles. When we allow the survey geometry to be disconnected but with a fixed total area, assuming $1\times 1$ sq. degrees patches as the fundamental building blocks of survey footprints, the best strategy is to locate the patches with $\sim 15$ degrees separation. This separation angle corresponds to the scale at which the two-point correlation function has a negative minimum. The best configuration allows for a factor 100 gain in the effective area coverage as well as a factor 2.5 improvement in the $S/N$ at high multipoles, yielding a much wider coverage of multipoles than in the compact geometry.
description: 15 pages, 14 figures, accepted for publication in MNRAS
Interelectron interactions and the RKKY potential between H adatoms in graphene
Creators: name: Buividovich, Pavel
name: Smith, Dominik
name: Ulybyshev, Maksim
name: von Smekal, Lorenz
Publisher: name: Universität Regensburg
Year: 2017
Subjects: subject: ;
subject: 530 Physik

description: We use first-principles quantum Monte Carlo simulations to study the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between hydrogen adatoms attached to a graphene sheet. We find that the pairwise RKKY interactions at distances of a few lattice spacings are strongly affected by interelectron interactions, in particular, the potential barrier between widely separated adatoms and the dimer configuration becomes wider and thus harder to penetrate. We also point out that antiferrromagnetic and charge density wave orderings have very different effects on the RKKY interaction. Finally, we analyze the stability of several regular adatom superlattices with respect to small displacements of a single adatom, distinguishing the cases of adatoms which populate either both or only one sublattice of the graphene lattice.
Theoretical study of ionization profiles of molecular clouds near supernova remnants: Tracing the hadronic origin of GeV gamma radiation
Creators: name: Schuppan, Florian
name: Röken, Christian
name: Tjus, Julia Becker
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Context: Since a few years, signatures of supernova remnants associated with molecular clouds have been detected in gamma rays. Whether these gamma rays are generated by cosmic ray electrons or by cosmic ray protons is usually not known. The detection of hadronic ionization signatures in spatial coincidence with gamma ray signatures can help to unambiguously identify supernova remnants as sources of cosmic ray protons. Methods: In order to calculate hadronic signatures from cosmic ray-induced ionization for an examination of the origin of the observed gamma rays, the transport equation for cosmic ray protons propagating in a molecular cloud, including the relevant momentum loss processes, is solved analytically and the proton flux at any position in the cloud is determined. Results: Since the solution of the transport equation is obtained for arbitrary source functions, it can be used for a variety of supernova remnants. The corresponding theoretical ionization rate, as a function of the penetration depth, is derived and compared to photoinduced ionization profiles in a case study with four supernova remnants associated with molecular clouds. Three of the remnants show a clear dominance of the hadronically induced ionization rate, while for one remnant, X-ray emission seems to dominate by a factor of 10. Conclusions: This is the first derivation of position-dependent profiles for cosmic ray-induced ionization with an analytic solution for arbitrary cosmic ray source spectra. The cosmic ray-induced ionization has to be compared to X-ray ionization for strong X-ray sources. For sources dominated by cosmic ray-induced ionization (e.g., W49B), the ionization profiles can be used in the future to map the spatial structure of hadronic gamma rays and rotation-vibrational lines induced by cosmic ray protons, helping to identify sources of hadronic cosmic rays.
description: published in Astronomy and Astrophysics, 20 pages, 17 figures
Neutron Star instabilities in full General Relativity using a $Γ=2.75$ ideal fluid
Creators: name: De Pietri, Roberto
name: Feo, Alessandra
name: Franci, Luca
name: Löffler, Frank
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present results about the effect of the use of a stiffer equation of state, namely the ideal-fluid $Γ=2.75$ ones, on the dynamical bar-mode instability in rapidly rotating polytropic models of neutron stars in full General Relativity. We determine the change on the critical value of the instability parameter $β$ for the emergence of the instability when the adiabatic index $Γ$ is changed from 2 to 2.75 in order to mimic the behavior of a realistic equation of state. In particular, we show that the threshold for the onset of the bar-mode instability is reduced by this change in the stiffness and give a precise quantification of the change in value of the critical parameter $β_c$. We also extend the analysis to lower values of $β$ and show that low-beta shear instabilities are present also in the case of matter described by a simple polytropic equation of state.
description: 16 pages, 16 figures
Landau levels in QCD
Creators: name: Bruckmann, F.
name: Endrődi, G.
name: Giordano, M.
name: Katz, S. D.
name: Kovács, T. G.
name: Pittler, F.
name: Wellnhofer, J.
Publisher: name: Universität Regensburg
Year: 2017
Subjects: subject: EXACTLY MASSLESS QUARKS; STRONG MAGNETIC-FIELD; SYMMETRY-BREAKING; CATALYSIS; LATTICE;
subject: 530 Physik

description: We present first evidence for the Landau level structure of Dirac eigenmodes in full QCD for nonzero background magnetic fields, based on first principles lattice simulations using staggered quarks. Our approach involves the identification of the lowest Landau level modes in two dimensions, where topological arguments ensure a clear separation of these modes from energetically higher states, and an expansion of the full four-dimensional modes in the basis of these two-dimensional states. We evaluate various fermionic observables including the quark condensate and the spin polarization in this basis to find how much the lowest Landau level contributes to them. The results allow for a deeper insight into the dynamics of quarks and gluons in background magnetic fields and may be directly compared to low-energy models of QCD employing the lowest Landau level approximation.
title: Die Mischung machts – zum Verhältnis von synchroner und asynchroner Lehre
Creators: name: Quante, Alina
Publisher: name: Zentrum für Hochschul- und Wissenschaftsdidaktik, Universität Regensburg
Year: 2021

description: Der Beitrag gibt Empfehlungen, in welchem Verhältnis synchrone und asynchrone Sitzungen bei digitalen Veranstaltungen stehen sollten und welches Format wofür besonders geeignet ist.
Hydrodynamic Coulomb drag of strongly correlated electron liquids
Creators: name: Apostolov, S. S.
name: Levchenko, A.
name: Andreev, A. V.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We develop a theory of Coulomb drag in ultraclean double layers with strongly correlated carriers. In the regime where the equilibration length of the electron liquid is shorter than the interlayer spacing the main contribution to the Coulomb drag arises from hydrodynamic density fluctuations. The latter consist of plasmons driven by fluctuating longitudinal stresses, and diffusive modes caused by temperature fluctuations and thermal expansion of the electron liquid. We express the drag resistivity in terms of the kinetic coefficients of the electron fluid. Our results are nonperturbative in interaction strength and do not assume Fermi-liquid behavior of the electron liquid.
description: 5 pages, 1 figure
Designing MOF Nanoarchitectures for Electrochemical Water Splitting
Creators: name: Zhang, Ben
name: Zheng, Yijuan
name: Ma, Tian
name: Yang, Chengdong
name: Peng, Yifei
name: Zhou, Zhihao
name: Zhou, Mi
name: Li, Shuang
name: Wang, Yinghan
name: Cheng, Chong
Publisher: name: Technische Universität Berlin
Year: 2021
Subjects: subject: 540 Chemie und zugeordnete Wissenschaften
subject: electrocatalytic nanostructures and electrocatalysts
subject: hydrogen evolution reaction
subject: metal–organic frameworks
subject: oxygen evolution reaction
subject: water splitting

description: Electrochemical water splitting has attracted significant attention as a key pathway for the development of renewable energy systems. Fabricating efficient electrocatalysts for these processes is intensely desired to reduce their overpotentials and facilitate practical applications. Recently, metal–organic framework (MOF) nanoarchitectures featuring ultrahigh surface areas, tunable nanostructures, and excellent porosities have emerged as promising materials for the development of highly active catalysts for electrochemical water splitting. Herein, the most pivotal advances in recent research on engineering MOF nanoarchitectures for efficient electrochemical water splitting are presented. First, the design of catalytic centers for MOF‐based/derived electrocatalysts is summarized and compared from the aspects of chemical composition optimization and structural functionalization at the atomic and molecular levels. Subsequently, the fast‐growing breakthroughs in catalytic activities, identification of highly active sites, and fundamental mechanisms are thoroughly discussed. Finally, a comprehensive commentary on the current primary challenges and future perspectives in water splitting and its commercialization for hydrogen production is provided. Hereby, new insights into the synthetic principles and electrocatalysis for designing MOF nanoarchitectures for the practical utilization of water splitting are offered, thus further promoting their future prosperity for a wide range of applications.
Ultraviolet fixed point and massive composite particles in TeV scales
Creators: name: Xue, She-Sheng
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present a further study of the dynamics of high-dimension fermion operators attributed to the theoretical inconsistency of the fundamental cutoff (quantum gravity) and the parity-violating gauge symmetry of the standard model. Studying the phase transition from a symmetry-breaking phase to a strong-coupling symmetric phase and the $β$-function behavior in terms of four-fermion coupling strength, we discuss the critical transition point as a ultraviolet-stable fixed point where a quantum field theory preserving the standard model gauge symmetry with composite particles can be realized. The form-factors and masses of composite particles at TeV scales are estimated by extrapolating the solution of renormalization-group equations from the infrared-stable fixed point where the quantum field theory of standard model is realized and its phenomenology including Higgs mass has been experimentally determined. We discuss the probability of composite-particle formation and decay that could be experimentally verified in the LHC by measuring the invariant mass of relevant final states and their peculiar kinetic distributions.
description: Both theoretical parts and in particular the predictions in experimental part have been clarified. Beside, the discussions on the lepton sector in the previous version (v1) have seen removed due to the length limit of the Letter, and will be submitted to elsewhere. The version (v2) reproduces the version (v1). I have corrected this error and the version (v3) should be final as appeared in PLB
Skewness and kurtosis of net baryon-number distributions at small values of the baryon chemical potential
Creators: name: Bazavov, A.
name: Ding, H.-T.
name: Hegde, P.
name: Kaczmarek, O.
name: Karsch, F.
name: Laermann, E.
name: Mukherjee, Swagato
name: Ohno, H.
name: Petreczky, P.
name: Rinaldi, E.
name: Sandmeyer, H.
name: Schmidt, C.
name: Schroeder, Chris
name: Sharma, S.
name: Soeldner, W.
name: Soltz, R. A.
name: Steinbrecher, P.
name: Vranas, P. M.
Publisher: name: Universität Regensburg
Year: 2017
Subjects: subject: PHASE-DIAGRAM; FREEZE-OUT; TEMPERATURE; RESTORATION; DENSITY;
subject: 530 Physik

description: We present results for the ratios of mean (MB), variance (sigma(2)(B)), skewness (SB) and kurtosis(kappa B) of net baryon-number fluctuations obtained in lattice QCD calculations with physical values of light and strange quark masses. Using next-to-leading order Taylor expansions in baryon chemical potential we find that qualitative features of these ratios closely resemble the corresponding experimentally measured cumulant ratios of net proton-number fluctuations for beam energies down to root s(NN) >= 19.6 GeV. We show that the difference in cumulant ratios for the mean net baryon-number, M-B/sigma(2)(B) = chi(1)(B) (T, mu(B)) / chi(2)(B) (T, mu(B)), and the normalized skewness, S-B sigma(B) = chi(B)(3) (T, mu(B)) / chi(B)(2) (T, mu B), naturally arises in QCD thermodynamics. Moreover, we establish a close relation between skewness and kurtosis ratios, S-B sigma(3)(B) / M-B = chi(B)(3) (T, mu(B)) / chi(B)(1) (T, mu(B)) and kappa(B)sigma(2)(B) = chi(B)(4) (T, mu(B)) /chi(B)(2) (T, mu(B)), valid at small values of the baryon chemical potential.
Consecutive β,β′‐Selective C(sp3)−H Silylation of Tertiary Amines with Dihydrosilanes Catalyzed by B(C6F5)3
Creators: name: Fang, Huaquan
name: Xie, Kaixue
name: Kemper, Sebastian
name: Oestreich, Martin
Publisher: name: Technische Universität Berlin
Year: 2021
Subjects: subject: 540 Chemie und zugeordnete Wissenschaften
subject: amines
subject: boron
subject: C−H activation
subject: Si−H activation
subject: silicon

description: Tris(pentafluorophenyl)borane has been found to catalyze the two‐fold C(sp3)−H silylation of various trialkylamine derivatives with dihydrosilanes, furnishing the corresponding 4‐silapiperidines in decent yields. The multi‐step reaction cascade involves amine‐to‐enamine dehydrogenation at two alkyl residues and two electrophilic silylation reactions of those enamines, one inter‐ and one intramolecular.
Diffusion in the Lorentz gas
Creators: name: Dettmann, Carl P.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The Lorentz gas, a point particle making mirror-like reflections from an extended collection of scatterers, has been a useful model of deterministic diffusion and related statistical properties for over a century. This survey summarises recent results, including periodic and aperiodic models, finite and infinite horizon, external fields, smooth or polygonal obstacles, and in the Boltzmann-Grad limit. New results are given for several moving particles and for obstacles with flat points. Finally, a variety of applications are presented.
description: 28 pages, 5 figures
Optimized Biocatalytic Synthesis of 2‐Selenopyrimidine Nucleosides by Transglycosylation**
Creators: name: Hellendahl, Katja F.
name: Kaspar, Felix
name: Zhou, Xinrui
name: Yang, Zhaoyi
name: Huang, Zhen
name: Neubauer, Peter
name: Kurreck, Anke
Publisher: name: Technische Universität Berlin
Year: 2021
Subjects: subject: 540 Chemie und zugeordnete Wissenschaften
subject: nucleosides
subject: selenium
subject: transglycosylation
subject: equilibrium constant
subject: nucleoside phosphorylase

description: Selenium‐modified nucleosides are powerful tools to study the structure and function of nucleic acids and their protein interactions. The widespread application of 2‐selenopyrimidine nucleosides is currently limited by low yields in established synthetic routes. Herein, we describe the optimization of the synthesis of 2‐Se‐uridine and 2‐Se‐thymidine derivatives by thermostable nucleoside phosphorylases in transglycosylation reactions using natural uridine or thymidine as sugar donors. Reactions were performed at 60 or 80 °C and at pH 9 under hypoxic conditions to improve the solubility and stability of the 2‐Se‐nucleobases in aqueous media. To optimize the conversion, the reaction equilibria in analytical transglycosylation reactions were studied. The equilibrium constants of phosphorolysis of the 2‐Se‐pyrimidines were between 5 and 10, and therefore differ by an order of magnitude from the equilibrium constants of any other known case. Hence, the thermodynamic properties of the target nucleosides are inherently unfavorable, and this complicates their synthesis significantly. A tenfold excess of sugar donor was needed to achieve 40−48 % conversion to the target nucleoside. Scale‐up of the optimized conditions provided four Se‐containing nucleosides in 6–40 % isolated yield, which compares favorably to established chemical routes.
Exciton broadening in WS2 /graphene heterostructures
Creators: name: Hill, Heather M.
name: Rigosi, Albert F.
name: Raja, Archana
name: Chernikov, Alexey
name: Roquelet, Cyrielle
name: Heinz, Tony F.
Publisher: name: Universität Regensburg
Year: 2017
Subjects: subject: DER-WAALS HETEROSTRUCTURES; TRANSITION-METAL DICHALCOGENIDES; MONOLAYER MOS2; ENERGY-TRANSFER; 2-DIMENSIONAL MATERIALS; CHARGE-TRANSFER; VALLEY POLARIZATION; TUNGSTEN DISULFIDE; ELECTRIC-FIELD; LAYER MOS2;
subject: 530 Physik

description: We have used optical spectroscopy to observe spectral broadening of WS2 exciton reflectance peaks in heterostructures of monolayer WS2 capped with mono- to few-layer graphene. The broadening is found to be similar for the A and B excitons and on the order of 5-10 meV. No strong dependence on the number of graphene layers was observed within experimental uncertainty. The broadening can be attributed to charge- and energy-transfer processes between the two materials, providing an observed lower bound for the corresponding time scales of 65 fs.
The Generation of Flood Damage Time Sequences
Creators: name: Breaden, John P.
Publisher: name: Kentucky Water Resources Research Institute, University of Kentucky
Year: 1971

description: Abstract:
There is a need in water resources planning to develop a procedure for determining the time pattern in which flood damages occur as a function of the rise and fall of the flood hydrograph. The widely-used approach for estimation of flood damages does not take into account the fact that the frequency of the annual flood peak may not be the same as the frequency of the total annual flood damages. As examples, several small storms during the year may do more damage than a single larger storm, or flood damages may be reduced by a reduction in flood duration rather than the flood peaks.
This report presents a digital computer subroutine DAMAGE which can be used to estimate the direct and indirect damages to property in the four basic categories of crop, field, urban, and public facilities as functions of the depth and duration of flooding, seasons, and the time laps between flood events. DAMAGE may be called with recorded or simulated annual hydrographs and used to analyze the time pattern of damages in the flood plain for optimizing the policies for operating reservoir flood control storage or for estimating the average annual damages for use in formulation of alternative flood control schemes.
Preparation of Knill-Lafamme-Milburn states based on superconducting qutrits
Creators: name: Liu, Qi-Gong
name: Wu, Qi-Cheng
name: Ji, Xin
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose two schemes for generating the Knill-Lafamme-Milburn (KLM) states of two distant polar molecules (PMs) ensembles respectively in two transmission-line resonators (TLRs) connected by a superconducting charge qutrit (SCQ), and of two SCQs in a TLR, respectively. Both of the schemes are robust against photon decay due to the virtual excitations of the microwave photons of the TLRs, and the spontaneous emission can be suppressed owing to the virtual transitions of the SCQs in the second scheme. In addition, the schemes have high controllability and feasibility under the current available techniques.
description: 19 pages, 3 figures
Giant Spin Lifetime Anisotropy in Graphene Induced by Proximity Effects
Creators: name: Cummings, Aron W.
name: Garcia, Jose H.
name: Fabian, Jaroslav
name: Roche, Stephan
Publisher: name: Universität Regensburg
Year: 2017
Subjects: subject: DER-WAALS HETEROSTRUCTURES; QUANTUM TRANSPORT; CRYSTALS;
subject: 530 Physik

description: We report on fundamental aspects of spin dynamics in heterostructures of graphene and transition metal dichalcogenides (TMDCs). By using realistic models derived from first principles we compute the spin lifetime anisotropy, defined as the ratio of lifetimes for spins pointing out of the graphene plane to those pointing in the plane. We find that the anisotropy can reach values of tens to hundreds, which is unprecedented for typical 2D systems with spin-orbit coupling and indicates a qualitatively new regime of spin relaxation. This behavior is mediated by spin-valley locking, which is strongly imprinted onto graphene by TMDCs. Our results indicate that this giant spin lifetime anisotropy can serve as an experimental signature of materials with strong spin-valley locking, including graphene-TMDC hetero-structures and TMDCs themselves. Additionally, materials with giant spin lifetime anisotropy can provide an exciting platform for manipulating the valley and spin degrees of freedom, and for designing novel spintronic devices.
A novel phase‐field approach to brittle damage mechanics of gradient metamaterials combining action formalism and history variable
Creators: name: Abali, Bilen Emek
name: Klunker, Andre
name: Barchiesi, Emilio
name: Placidi, Luca
Publisher: name: Technische Universität Berlin
Year: 2021
Subjects: subject: 530 Physik
subject: damage mechanics
subject: generalized mechanics
subject: metamaterials
subject: phase‐field
subject: variational formalism

description: Metamaterials response is generally modeled by generalized continuum based theories. Their inherent substructure leads to a necessity for higher‐order theories, and especially in damage mechanics, such a generalization is difficult to acquire. We exploit the action formalism in order to obtain the governing equations in generalized damage mechanics for metamaterials. Additionally, by using auxilliary variables, the variational formulation is endowed with the first rate of damage variable that is missing in standard approaches. The presented action formalism with auxilliary variables leads directly to the weak form. We implement a finite element method based approach by using open‐source computing platform called FEniCS and solve this weak in order to obtain the deformation and damage numerically. Metamaterials simulations are demonstrated for simple geometries in mixed mode (I and II) as well as in mode III.
Photon and photino as Nambu-Goldstone zero modes in an emergent SUSY QED
Creators: name: Chkareuli, J. L.
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We argue that supersymmetry with its well known advantages, such as naturalness, grand unification and dark matter candidate seems to possess one more attractive feature: it may trigger, through its own spontaneous violation in the visible sector, a dynamical generation of gauge fields as massless Nambu-Goldstone modes during which physical Lorentz invariance itself is ultimately preserved. We consider the supersymmetric QED model extended by an arbitrary polynomial potential of massive vector superfield that breaks gauge invariance in the SUSY invariant phase. However, the requirement of vacuum stability in such class of models makes both supersymmetry and Lorentz invariance to become spontaneously broken. As a consequence, massless photino and photon appear as the corresponding Nambu-Goldstone zero modes in an emergent SUSY QED, and also a special gauge invariance is simultaneously generated. Due to this invariance all observable relativistically noninvariant effects appear to be completely cancelled out among themselves and physical Lorentz invariance is recovered. Nevertheless, such theories may have an inevitable observational evidence in terms of the goldstino-photino like state presented in the low-energy particle spectrum. Its study is of a special interest for this class of SUSY models that, apart from some indication of an emergence nature of QED and the Standard Model, may appreciably extend the scope of SUSY breaking physics being actively studied in recent years.
description: 23 pages, to appear in Eur. Phys. J. C 74 (2014) issue 6. arXiv admin note: substantial text overlap with arXiv:1305.6898
Audience expectations in international bargaining
Creators: name: Walsh, David Hunter
Publisher: name: No Publisher Supplied
Year: 2018

description: This dissertation project proposes a novel theoretical framework for understanding theconstraining role that opinionated audiences play in international bargaining. The well-knownaudience cost paradigm assumes that domestic audiences have a strong generalpreference for their leader making good on the threats they issue, which has led to a numberof serious empirical challenges for that paradigm. I argue on psychological grounds thataudiences' reactionary tendencies to policy shifts of all kinds effectively generate a similarbut distinct expectation cost; these patterns of reaction, when fully understood, can explaina wide range of empirical phenomena in international security, including but not limited tothose with which audience cost theory is concerned.The theory indicates that: the median voter theorem generally does not hold over time;positive reactions to popular shifts are always weaker than they would otherwise be; and,ultimately, acting in an inconsistent manner leads inevitably and unconditionally to a lossof domestic approval which can be used for signaling purposes in international bargaining.Most importantly, this theory can provide a unique and more proper explanation forthe democratic peace phenomenon: the generally dovish attitudes that democracies' audienceshave toward other democracies interact with their deviations from classical utility maximizationto produce a virtuous cycle of non-conflict.Most chapters constitute empirical tests of the theory, focusing on the quantifiable existence of expectation costs as well as their qualitative nuance. Nonlinear regression models on ANES panel data exhibit the fact that voters' reactions to policy shifts as they perceive them are subject to loss aversion, as predicted by prospect theory. Qualitative studies of the four cases in which a U.S. president violated a major campaign promise relating to foreign policy provide more comprehensive evidence of the expectation cost mechanism at work in real and substantively important cases of international bargaining.