cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Gravitational potential in spherical topologies
Creators: name: Vigneron, Quentin
name: Roukema, Boudewijn F.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the properties of the Newtonian gravitational potential in a spherical Universe for different topologies. For this, we use the non-Euclidean Newtonian theory developed in Vigneron [2022, Class. & Quantum Gravity, 39, 155006] describing Newtonian gravitation in a spherical or hyperbolic Universe. The potential is calculated for a point mass in all the globally homogeneous regular spherical topologies, i.e. whose fundamental domain is unique and is a platonic solid. We provide the exact solution and the Taylor expansion series of the potential at a test position near the point mass. We show that the odd terms of the expansion can be interpreted as coming from the presence of a non-zero spatial scalar curvature, while the even terms relate to the closed nature of the topological space. A consequence is that, compared to the point mass solution in a 3-torus, widely used in Newtonian cosmological simulations, the spherical cases all feature an additional attractive first order term dependent solely on the spatial curvature. The choice of topology only affects the potential at second order and higher. For typical estimates of cosmological scales (curvature and topology), the strongest topological effect occurs in the case of the Poincaré dodecahedral space, but in general the effect of curvature dominates over topology. We also provide the set of equations that can be used to perform $N$-body simulations of structure formation in spherical topologies.
description: Accepted in Physical Review D, 12 pages, 4 tables, calculation source code at https://codeberg.org/boud/topoaccel
Anomalous Symmetry Fractionalization and Surface Topological Order
Creators: name: Chen, Xie
name: Burnell, Fiona J.
name: Vishwanath, Ashvin
name: Fidkowski, Lukasz
Publisher: name: arXiv
Year: 2014
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In addition to possessing fractional statistics, anyon excitations of a 2D topologically ordered state can realize symmetry in distinct ways , leading to a variety of symmetry enriched topological (SET) phases. While the symmetry fractionalization must be consistent with the fusion and braiding rules of the anyons, not all ostensibly consistent symmetry fractionalizations can be realized in 2D systems. Instead, certain `anomalous' SETs can only occur on the surface of a 3D symmetry protected topological (SPT) phase. In this paper we describe a procedure for determining whether an SET of a discrete, onsite, unitary symmetry group $G$ is anomalous or not. The basic idea is to gauge the symmetry and expose the anomaly as an obstruction to a consistent topological theory combining both the original anyons and the gauge fluxes. Utilizing a result of Etingof, Nikshych, and Ostrik, we point out that a class of obstructions are captured by the fourth cohomology group $H^4( G, \,U(1))$, which also precisely labels the set of 3D SPT phases, with symmetry group $G$. We thus establish a general bulk-boundary correspondence between the anomalous SET and the 3d bulk SPT whose surface termination realizes it. We illustrate this idea using the chiral spin liquid ($U(1)_2$) topological order with a reduced symmetry $\mathbb{Z}_2 \times \mathbb{Z}_2 \subset SO(3)$, which can act on the semion quasiparticle in an anomalous way. We construct exactly solved 3d SPT models realizing the anomalous surface terminations, and demonstrate that they are non-trivial by computing three loop braiding statistics. Possible extensions to anti-unitary symmetries are also discussed.
description: 18 pages + 3 pages appendices. v2: added section on identifying the SPT order from nontrivial loop statistics in the 3D bulk with projective semion surface state
A filtered no arbitrage model for term structures from noisy data
Creators: name: Gombani, Andrea
name: Jaschke, Stefan R.
name: Runggaldier, Wolfgang R.
Publisher: name: Weierstrass Institute
Year: 2002
Subjects: subject: term structure of interest rates
subject: linear estimation
subject: Kalman filter
subject: 93E11
subject: 60G35

description: We consider an affine term structure model of interest rates, where the factors satisfy a linear diffusion equation. We assume that the information available to an agent comes from observing the yields of a finite number of traded bonds and that this information is not sufficient to reconstruct exactly the factors. We derive a method to obtain arbitrage-free prices of illiquid or non traded bonds that are compatible with the available incomplete information. The method is based on an application of the Kalman filter for linear Gaussian systems.
title: EU-Beihilfen an gemeinwirtschaftliche Unternehmen
title: Eine mehrdimensionale Betrachtung
titleType: AlternativeTitle
Creators: name: Oehl, Benedikt
Publisher: name: TU Dortmund
Year: 2022
Subjects: subject: EU-Beihilfen
subject: Gemeinwirtschaftlichkeit
subject: Daseinsvorsorge
subject: AEUV
subject: 340
subject: Beihilfenrecht
subject: Gemeinwesen
subject: Daseinsvorsorge

description: Um die Funktionalität eines Gemeinwesens hinreichend gewährleisten zu können, ist durch den einzelnen Nationalstaat eine ausreichende Versorgung seiner Bevölkerung mit öffentlichen Dienstleistungen sicherzustellen. Die Bereitstellung dieser öffentlichen Dienstleistungen im Sinne einer Daseinsvorsorge obliegt innerhalb der Europäischen Union dabei den einzelnen Mitgliedsstaaten. Zur eigentlichen Leistungserbringung bedienen sich die Mitgliedsstaaten überwiegend privatwirtschaftlichen Unternehmen, welche mit dieser Aufgabenerfüllung betraut werden. Hierbei werden durch die Mitgliedsstaaten verbindliche Vorgaben für diese Dienstleistungen zur Daseinsvorsorge festgelegt. Aus diesem Umstand ergibt sich, dass diese Dienstleistungen für die erbringenden privatwirtschaftlichen Unternehmen oft nicht kostendeckend betrieben werden können und so folglich am freien Markt nicht im geforderten Maße erbracht werden würden. Aus diesem Grund gewähren die Mitgliedsstaaten den mit Dienstleistungen von allgemeinem wirtschaftlichen Interesse (DAWI) betrauten Unternehmen Zuwendungen, um die gemeinwirtschaftlich bedingten Aufwendungen zu kompensieren. Staatliche Zuwendungen stellen allerdings einen Eingriff in den freien Markt dar, welches dem Grundgedanken auf einen freien Wettbewerb innerhalb der Europäischen Union zuwiderläuft. Es stellt sich daher die Frage, inwieweit Zuwendungen an betraute Unternehmen mit dem europäischen Beihilfenrecht vereinbar sind. Diese Dissertation hat einerseits den Anspruch, einen Überblick über das europäische Beihilfenrecht zu offerieren und dabei die relevanten Begrifflichkeiten zu erläutern. Andererseits darzustellen, inwieweit diese Zuwendungen notwendig und geboten sind. Um die gegenwärtige Rechtsprechung der Europäischen Gerichte und die Entscheidungspraxis der Europäischen Kommission im Sinne eines dualistischen Systems im gebotenen Maße bewerten zu können, wurde eine quantitative Datenanalyse betreffend DAWI durchgeführt. Im Ergebnis kann festgestellt werden, dass sowohl der Anteil von Daseinsvorsorgeleistungen in den einzelnen Mitgliedsstaaten wie auch das einzelstaatliche Verständnis der Begrifflichkeiten stark heterogen ist. Das Europäische Beihilfenrecht berücksichtigt dieses hinreichend und bietet den einzelnen Akteuren ein ausreichendes Regelwerk an, um einen guten Interessenausgleich zwischen diesen Antipoden zu gewährleisten. Im Zuge des gesamtgesellschaftlich stattfindenden Wandels, zeigt sich das europäische Beihilfenrecht nicht nur als statisches Konstrukt, sondern trägt diesem dynamischen Anpassungsprozess auch unter Zuhilfenahme seiner umfassenden historischen Genese gebührend Rechnung.
Bouquets, vertex covers and edge ideals
Creators: name: Erey, Nursel
Publisher: name: arXiv
Year: 2014
Subjects: subject: Commutative Algebra (math.AC)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: We give a new combinatorial characterization of the big height of a squarefree monomial ideal leading to a new bound for the projective dimension of a monomial ideal.
Generating Haar-uniform Randomness using Stochastic Quantum Walks on a Photonic Chip
Creators: name: Tang, Hao
name: Banchi, Leonardo
name: Wang, Tian-Yu
name: Shang, Xiao-Wen
name: Tan, Xi
name: Zhou, Wen-Hao
name: Feng, Zhen
name: Pal, Anurag
name: Li, Hang
name: Hu, Cheng-Qiu
name: Kim, M. S.
name: Jin, Xian-Min
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: As random operations for quantum systems are intensively used in various quantum information tasks, a trustworthy measure of the randomness in quantum operations is highly demanded. The Haar measure of randomness is a useful tool with wide applications such as boson sampling. Recently, a theoretical protocol was proposed to combine quantum control theory and driven stochastic quantum walks to generate Haar-uniform random operations. This opens up a promising route to converting classical randomness to quantum randomness. Here, we implement a two-dimensional stochastic quantum walk on the integrated photonic chip and demonstrate that the average of all distribution profiles converges to the even distribution when the evolution length increases, suggesting the 1-pad Haar-uniform randomness. We further show that our two-dimensional array outperforms the one-dimensional array of the same number of waveguide for the speed of convergence. Our work demonstrates a scalable and robust way to generate Haar-uniform randomness that can provide useful building blocks to boost future quantum information techniques.
description: 6 pages and 4 figures for main text ; 16 pages and 16 figures for supplementary note
Metal insulator transitions in perovskite SrIrO3 thin films
Creators: name: Biswas, Abhijit
name: Kim, Ki-Seok
name: Jeong, Yoon Hee
Publisher: name: arXiv
Year: 2013
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Understanding of metal insulator transitions in a strongly correlated system, driven by Anderson localization (disorder) and/or Mott localization (correlation), is a long standing problem in condensed matter physics. The prevailing fundamental question would be how these two mechanisms contrive to accomplish emergent anomalous behaviors. Here, we have grown high quality perovskite SrIrO3 thin films, containing a strong spin orbit coupled 5d element Ir, on various substrates such as GdScO3 (110), DyScO3 (110), SrTiO3 (001), and NdGaO3 (110) with increasing lattice mismatch, in order to carry out a systematic study on the transport properties. We found that metal insulator transitions can be induced in this system; by either reducing thickness (on best lattice matched substrate) or changing degree of lattice strain (by lattice mismatch between film and substrates) of films. Surprisingly these two pathways seek two distinct types of metal insulator transitions; the former falls into disorder driven Anderson type whereas the latter turns out to be of unconventional Mott-Anderson type with the interplay of disorder and correlation. More interestingly, in the metallic phases of SrIrO3, unusual non-Fermi liquid characteristics emerge in resistivity as the resistivity exponent evolves from from 4/5 to 1 to 3/2 with increasing lattice strain. We discuss theoretical implications of these phenomena to shed light on the metal insulator transitions.
description: Some figures are redrawn, appears in Journal of Applied Physics
M-Chem: a modular software package for molecular simulation that spans scientific domains
Creators: name: Witek, Jagna
name: Heindel, Joseph P.
name: Guan, Xingyi
name: Leven, Itai
name: Hao, Hongxia
name: Naullage, Pavithra
name: LaCour, Allen
name: Sami, Selim
name: Menger, M. F. S. J.
name: Cofer-Shabica, D. Vale
name: Berquist, Eric
name: Faraji, Shirin
name: Epifanovsky, Evgeny
name: Head-Gordon, Teresa
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Biophysics
subject: Biochemistry
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: 80699 Information Systems not elsewhere classified
subject: FOS: Computer and information sciences
subject: Inorganic Chemistry
subject: Computational Biology

description: We present a new software package called M-Chem that is designed from scratch in C++ and parallelised on shared-memory multi-core architectures to facilitate efficient molecular simulations. Currently, M-Chem is a fast molecular dynamics (MD) engine that supports the evaluation of energies and forces from two-body to many-body all-atom potentials, reactive force fields, coarse-grained models, combined quantum mechanics molecular mechanics (QM/MM) models, and external force drivers from machine learning, augmented by algorithms that are focused on gains in computational simulation times. M-Chem also includes a range of standard simulation capabilities including thermostats, barostats, multi-timestepping, and periodic cells, as well as newer methods such as fast extended Lagrangians and high quality electrostatic potential generation. At present M-Chem is a developer friendly environment in which we encourage new software contributors from diverse fields to build their algorithms, models, and methods in our modular framework. The long-term objective of M-Chem is to create an interdisciplinary platform for computational methods with applications ranging from biomolecular simulations, reactive chemistry, to materials research.
Bayesian Shrinkage Estimation for Stratified Count Data
Creators: name: Hamura, Yasuyuki
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics

description: In this paper, we consider simultaneous estimation of Poisson parameters in situations where we can use side information in aggregated data. We use standardized squared error and entropy loss functions. Bayesian shrinkage estimators are derived based on conjugate priors. We compare the risk functions of direct estimators and Bayesian estimators with respect to different priors that are constructed based on different subsets of observations. We obtain conditions for domination and also prove minimaxity and admissibility in a simple setting.
description: 48 pages
title: The transfer and mobilisation of sustainability concepts to Abu Dhabi:
title: the case of Masdar and the Urban Planning Council.
titleType: Subtitle
Creators: name: Mascarenhas, Prianjali
Publisher: name: London School of Economics and Political Science (LSE)
Year: 2018
Subjects: subject: HT Communities. Classes. Races

description: This thesis aims to understand the politics, implications and interpretations associated with the transfer and mobilisation of sustainability concepts from elsewhere into Abu Dhabi. The emirate’s pursuit of sustainability encompasses opportunities and also complexities which require trade-offs and creative solutions amidst the demands of globalisation and the existing authoritarian status quo. Exploring the rationale for the transfer of sustainability concepts from elsewhere into Abu Dhabi and its subsequent mobilisation in the local context expands our understanding of the different mechanisms, processes, platforms and change agents that enable sustainability-driven assemblages to thrive.
 By juxtaposing theoretical constructs from the academic literature on policy mobility, policy transfer and related governance, against empirical data in the areas of housing, transport, energy and urban design, nuanced meanings and experiences associated with the transfer and mobilisation of sustainability emerge. By situating Abu Dhabi’s sustainability developments relationally within the context of the Gulf Co-operation Council (GCC) nations, exploring the historical, social and political factors that have influenced the adaptation and interpretation of foreign sustainability concepts at multiple levels including the institutional level at Masdar and the UPC, this research on Abu Dhabi adds new knowledge to studies on policy mobility. Similarly, solutions that emerge as a result of concepts and actors moving and engaging across time and space expands our understanding of policy transfer processes in an authoritarian context. The nuances of the local context cannot be underestimated, particularly around the assertion of authoritarian power, persisting inequalities, and the forms of knowledge production and governance that emerge.
Role of Surgical and Medical Management of Chronic Thromboembolic Pulmonary Hypertension: A Systematic Review
Creators: name: Crowley, Alexandra
name: Banfield, Megan
name: Gupta, Aditi
name: Raj, Rhea
name: Thomas, Sneha
name: Gorantla, Vasavi R.
Publisher: name: figshare
Year: 2023
Subjects: Cardiology (incl. cardiovascular diseases)

description: A systematic review comparing pulmonary endarterectomy, balloon pulmonary angioplasty and anticoagulant therapies on the treatment of chronic thromboembolic pulmonary hypertension.
VIX pricing in the rBergomi model under a regime switching change of measure
Creators: name: Guerreiro, Henrique
name: Guerra, João
Publisher: name: arXiv
Year: 2022
Subjects: subject: Pricing of Securities (q-fin.PR)
subject: FOS: Economics and business
subject: 60G22, 60J28, 91G20, 60J20, 91G60, 45D05

description: The rBergomi model under the physical measure consists of modeling the log-variance as a truncated Brownian semi-stationary process. Then, a deterministic change of measure is applied. The rBergomi model is able to reproduce observed market SP500 smiles with few parameters, but by virtue of the deterministic change of measure, produces flat VIX smiles, in contrast to the upward sloping smiles observed in the market. We use the exact solution for a certain inhomogeneous fractional Ornstein-Uhlenbeck equation to build a regime switching stochastic change of measure for the rBergomi model that both yields upward slopping VIX smiles and is equipped with an efficient semi-analytic Monte Carlo method to price VIX options. The model also allows an approximation of the VIX, which leads to a significant reduction of the computational cost of pricing VIX options and futures. A variance reduction technique based on the underlying continuous time Markov chain allows us to further reduce the computational cost. We verify the capabilities of our model by calibrating it to observed market smiles and discuss the results.
description: 34 pages, 9 figures
Stability of <100> Dislocations formed in W Collision Cascades
Creators: name: Bhardwaj, Utkarsh
name: Sand, Andread E.
name: Warrier, Manoj
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Experiments and simulations both have verified the presence of <100> dislocations in irradiated W. It is essential to know the properties and behavior of these defects to study the evolution of microstructures at higher scales. We study the thermal stability and transition mechanism of various <100> dislocations formed in a molecular dynamics (MD) database of 230 collision cascades using three different interatomic potentials. The energy of transition of <100> dislocations to more stable <111> dislocations is calculated for various defects that transition within the 100 nanosecond time scale readily accessible to MD. The stability of <100> dislocations increases with size, but the trend is not strict. The reasons for irregularities are the aspects of internal configuration such as (i) the arrangement of <100> directed crowdions within the defect, (ii) the presence and arrangement of non-<100> crowdions on the fringes of the defect. We show the typical pathways of transitions and discuss the sources of instability in the defect configurations. We also discuss the similarities and differences in stability found across different interatomic potentials. Understanding transition mechanisms and internal morphology gives insights into the stability of <100> dislocations, useful in higher scale models such as Kinetic Monte Carlo (KMC).
description: 18 pages, 6 figures, presented at MoD-PMI 2021 workshop and IAEA-CCN 2021 meeting
Critical exponents of the 3d Ising and related models from Conformal Bootstrap
Creators: name: Gliozzi, Ferdinando
name: Rago, Antonio
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The constraints of conformal bootstrap are applied to investigate a set of conformal field theories in various dimensions. The prescriptions can be applied to both unitary and non unitary theories allowing for the study of the spectrum of low-lying primary operators of the theory. We evaluate the lowest scaling dimensions of the local operators associated with the Yang-Lee edge singularity for $2 \le D \le 6$. Likewise we obtain the scaling dimensions of six scalars and four spinning operators for the 3d critical Ising model. Our findings are in agreement with existing results to a per mill precision and estimate several new exponents.
description: Latex, 19 pages, 9 figures, v4: updated literature results
Graphs with $G^p$-connected medians
Creators: name: Bénéteau, Laurine
name: Chalopin, Jérémie
name: Chepoi, Victor
name: Vaxès, Yann
Publisher: name: arXiv
Year: 2022
Subjects: subject: Combinatorics (math.CO)
subject: Discrete Mathematics (cs.DM)
subject: Optimization and Control (math.OC)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: The median of a graph $G$ with weighted vertices is the set of all vertices $x$ minimizing the sum of weighted distances from $x$ to the vertices of $G$. For any integer $p\ge 2$, we characterize the graphs in which, with respect to any non-negative weights, median sets always induce connected subgraphs in the $p$th power $G^p$ of $G$. This extends some characterizations of graphs with connected medians (case $p=1$) provided by Bandelt and Chepoi (2002). The characteristic conditions can be tested in polynomial time for any $p$. We also show that several important classes of graphs in metric graph theory, including bridged graphs (and thus chordal graphs), graphs with convex balls, bucolic graphs, and bipartite absolute retracts, have $G^2$-connected medians. Extending the result of Bandelt and Chepoi that basis graphs of matroids are graphs with connected medians, we characterize the isometric subgraphs of Johnson graphs and of halved-cubes with connected medians.
description: 34 pages, 7 figures
Stochastic Lagrangian flows on the group of volume-preserving homeomorphisms of the spheres
Creators: name: Luo, Dejun
Publisher: name: arXiv
Year: 2013
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 58J65, 60H10

description: We consider stochastic differential equations on the group of volume-preserving homeomorphisms of the sphere $S^d\,(d\geq 2)$. The diffusion part is given by the divergence free eigenvector fields of the Laplacian acting on $L^2$-vector fields, while the drift is some other divergence free vector field. We show that the equation generates a unique flow of measure-preserving homeomorphisms when the drift has first order Sobolev regularity, and derive a formula for the distance between two Lagrangian flows. We also compute the rotation process of two particles on the sphere $S^2$ when they are close to each other.
description: 20 pages. It has been accepted by Stochastics
Extracting perfect GHZ states from imperfect weighted graph states via entanglement concentration
Creators: name: Frantzeskakis, Rafail
name: Liu, Chenxu
name: Raissi, Zahra
name: Barnes, Edwin
name: Economou, Sophia E.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Photonic GHZ states serve as the central resource for a number of important applications in quantum information science, including secret sharing, sensing, and fusion-based quantum computing. The use of photon-emitter entangling gates is a promising approach to creating these states that sidesteps many of the difficulties associated with intrinsically probabilistic methods based on linear optics. However, the efficient creation of high-fidelity GHZ states of many photons remains an outstanding challenge due to both coherent and incoherent errors during the generation process. Here, we propose an entanglement concentration protocol that is capable of generating perfect GHZ states using only local gates and measurements on imperfect weighted graph states. We show that our protocol is both efficient and robust to incoherent noise errors.
description: 11 pages, 8 figures
On the construction and properties of weak solutions describing dynamic cavitation
Creators: name: Miroshnikov, Alexey
name: Tzavaras, Athanasios E.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Analysis of PDEs (math.AP)
subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 35L67, 35L70, 74B20, 74H20, 74H60

description: We consider the problem of dynamic cavity formation in isotropic compressible nonlinear elastic media. For the equations of radial elasticity we construct self-similar weak solutions that describe a cavity emanating from a state of uniform deformation. For dimensions $d =2, 3$ we show that cavity formation is necessarily associated with a unique precursor shock. We also study the bifurcation diagram and do a detailed analysis of the singular asymptotics associated to cavity initiation as a function of the cavity speed of the self-similar profiles. We show that for stress free cavities the critical stretching associated with dynamically cavitating solutions coincides with the critical stretching in the bifurcation diagram of equilibrium elasticity. Our analysis treats both stress-free cavities and cavities with contents.
description: 49 pages
title: Rigid gauges and F-zips, and the fundamental sheaf of gauges Gn
Creators: name: Schnellinger, Felix
Publisher: name: Universität Regensburg
Year: 2009
Subjects: subject: Algebraische Geometrie , Kristalline Kohomologie , , algebraic geometry , crystalline cohomology
subject: 510 Mathematik

description: We establish an equivalence of categories between a category of gauges and Moonens and Wedhorns category of F-zips. We prove that cohomology of Fontaines and Jannsens sheaf Gn is equal for different good topologies.
description: Wir stellen eine Kategorienäquivalenz zwischen einer Kategorie von Gauges und Moonens und Wedhorns Kategorie der F-zips her. Wir beweisen, dass die Kohomologie von Fontaines und Jannsens Garbe Gn für verschiedene gute Topologien gleich ist.
Design of a hybrid Mie-Tamm photonic structure as a highly directional GHz single-photon source
Creators: name: Llorens, José M.
name: Alén, Benito
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We present a photonic structure where Mie, Tamm, and surface plasmon optical modes can be tailored to enhance the brightness of an embedded single-photon emitter. Contrary to most proposals, the structure is designed for excitation and collection through the substrate side. The front surface can be used instead to arrange metal contacts which serve both, as electrical gates and optical mirrors. The design is particularized for InGaAs QDs on GaAs resulting in an outcoupled single-photon rate exceeding 3 GHz in a narrow cone of NA = 0.17. The fabrication tolerances are also discussed.
Autonomous surface watercraft
Creators: name: Cardoza, Miguel A.
name: Benedict, Sarah
name: Mayoral, Anne
name: Bennett, Matthew
name: Hughes, J. Clark
name: Tucker, Donald
Publisher: name: United States Patent and Trademark Office
Year: 2005
Subjects: subject: B63B22/18
subject: B63B35/00
subject: B63C11/42
subject: B63B2035/007
subject: 114/144.RE

description: An autonomous surface watercraft is disclosed. The watercraft may include a control module, a communications module, a power management module, a differential thrust propulsion system, and a navigation module. One or more sensors may be provided internal to the watercraft and/or coupled to a sensor module coupling point on the watercraft. An operator may provide the watercraft with mission parameters such as but not limited to station point(s), a sensing location or area, a sensing duration, and/or a sensing time. The watercraft may determine a course heading to reach a station point or sensing area. The control module may control the propulsion system to reach the station point and for station keeping. The watercraft may gather sensor data. The sensor data may be analyzed, filtered, stored in memory and/or transmitted to a control center. The control center may receive real-time data from a plurality of such watercraft.
Bananas: multi-edge graphs and their Feynman integrals
Creators: name: Kreimer, Dirk
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences
subject: 81T18

description: We consider multi-edge or banana graphs $b_n$ on $n$ internal edges $e_i$ with different masses $m_i$. We focus on the cut banana graphs $\Im(Φ_R(b_n))$ from which the full result $Φ_R(b_n)$ can be derived through dispersion. We give a recursive definition of $\Im(Φ_R(b_n))$ through iterated integrals. We discuss the structure of this iterated integral in detail. A discussion of accompanying differential equations, of monodromy and of a basis of master integrals is included.
description: 43 pages, 7 figures, minor corrections
Which nuclear shape generates the strongest attraction on a relativistic electron? An open problem in relativistic quantum mechanics
Creators: name: Esteban, Maria J.
name: Lewin, Mathieu
name: Séré, Eric
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: In this article we formulate several conjectures concerning the lowest eigenvalue of a Dirac operator with an external electrostatic potential. The latter describes a relativistic quantum electron moving in the field of some (pointwise or extended) nuclei. The main question we ask is whether the eigenvalue is minimal when the nuclear charge is concentrated at one single point. This well-known property in nonrelativistic quantum mechanics has escaped all attempts of proof in the relativistic case.
description: Mathematics Going Forward, In press
Cumulant mapping as the basis of multi-dimensional spectrometry
Creators: name: Frasinski, Leszek J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Biological Physics (physics.bio-ph)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Cumulant mapping employs a statistical reconstruction of the whole by sampling its parts. The theory developed in this work formalises and extends ad hoc methods of `multi-fold' or `multi-dimensional' covariance mapping. Explicit formulae have been derived for the expected values of up to the 6th cumulant and the variance has been calculated for up to the 4th cumulant. A method of extending these formulae to higher cumulants has been described. The formulae take into account reduced fragment detection efficiency and a background from uncorrelated events. Number of samples needed for suppressing the statistical noise to a required level can be estimated using Matlab code included in Supplemental Material. The theory can be used to assess the experimental feasibility of studying molecular fragmentations induced by femtosecond or x-ray free-electron lasers. It is also relevant for extending the conventional mass spectrometry of biomolecules to multiple dimensions.
description: 13 pages, 6 figures; inconsequential mistakes in Eq. 8 corrected, a few typos weeded out, irrelevant comments from Matlab code removed
Analysis of the Potential Field and Equilibrium Points of Irregular-shaped Minor Celestial Bodies
Creators: name: Wang, Xianyu
name: Jiang, Yu
name: Gong, Shengping
Publisher: name: arXiv
Year: 2014
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The equilibrium points of the gravitational potential field of minor celestial bodies, including asteroids, comets, and irregular satellites of planets, are studied. In order to understand better the orbital dynamics of massless particles moving near celestial minor bodies and their internal structure, both internal and external equilibrium points of the potential field of the body are analyzed. In this paper, the location and stability of the equilibrium points of 23 minor celestial bodies are presented. In addition, the contour plots of the gravitational effective potential of these minor bodies are used to point out the differences between them. Furthermore, stability and topological classifications of equilibrium points are discussed, which clearly illustrate the topological structure near the equilibrium points and help to have an insight into the orbital dynamics around the irregular-shaped minor celestial bodies. The results obtained here show that there is at least one equilibrium point in the potential field of a minor celestial body, and the number of equilibrium points could be one, five, seven, and nine, which are all odd integers. It is found that for some irregular-shaped celestial bodies, there are more than four equilibrium points outside the bodies while for some others there are no external equilibrium points. If a celestial body has one equilibrium point inside the body, this one is more likely linearly stable.
description: 33pages, 1figure in Astrophysics and Space Science (2014)
An analysis of crystal cleavage in the passage from atomistic models to continuum theory
Creators: name: Friedrich, Manuel
name: Schmidt, Bernd
Publisher: name: arXiv
Year: 2013
Subjects: subject: Analysis of PDEs (math.AP)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 74R10, 49J45, 70G75

description: We study the behavior of atomistic models in general dimensions under uniaxial tension and investigate the system for critical fracture loads. We rigorously prove that in the discrete-to-continuum limit the minimal energy satisfies a particular cleavage law with quadratic response to small boundary displacements followed by a sharp constant cut-off beyond some critical value. Moreover, we show that the minimal energy is attained by homogeneous elastic configurations in the subcritical case and that beyond critical loading cleavage along specific crystallographic hyperplanes is energetically favorable. In particular, our results apply to mass spring models with full nearest and next-to-nearest pair interactions and provide the limiting minimal energy and minimal configurations.
description: The final publication is available at springerlink.com
Blind Orthogonal Least Squares based Compressive Spectrum Sensing
Creators: name: Lu, Liyang
name: Xu, Wenbo
name: Wang, Yue
name: Tian, Zhi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: As an enabling technique of cognitive radio (CR), compressive spectrum sensing (CSS) based on compressive sensing (CS) can detect the spectrum opportunities from wide frequency bands efficiently and accurately by using sub-Nyquist sampling rate. However, the sensing performance of most existing CSS excessively relies on the prior information such as spectrum sparsity or noise variance. Thus, a key challenge in practical CSS is how to work effectively even in the absence of such information. In this paper, we propose a blind orthogonal least squares based CSS algorithm (B-OLS-CSS), which functions properly without the requirement of prior information. Specifically, we develop a novel blind stopping rule for the OLS algorithm based on its probabilistic recovery condition. This innovative rule gets rid of the need of the spectrum sparsity or noise information, but only requires the computational-feasible mutual incoherence property of the given measurement matrix. Our theoretical analysis indicates that the signal-to-noise ratio required by the proposed B-OLS-CSS for achieving a certain sensing accuracy is relaxed than that by the benchmark CSS using the OMP algorithm, which is verified by extensive simulation results.
description: 14 figures, IEEE Transactions on Vehicular Technology (early access), Jun. 2023
Optically-induced magnetization switching in NiCo2O4 thin films using ultrafast lasers
Creators: name: Takahashi, Ryunosuke
name: Ohkochi, Takuo
name: Kan, Daisuke
name: Shimakawa, Yuichi
name: Wadati, Hiroki
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences
subject: J.2
subject: 93-05

description: Recently, all-optical magnetization control has been garnering considerable attention in realizing next-generation ultrafast magnetic information devices. Here, employing a magneto-optical Kerr effect (MOKE) microscope, we observed the laser-induced magnetization switching of ferrimagnetic oxide NiCo2O4 (NCO) epitaxial thin films with perpendicular magnetic anisotropy, where the sample was pumped at 1030-nm laser pulses, and magnetic domain images were acquired via the MOKE microscope with a white light emitting diode. Laser pulses irradiated an NCO thin film at various temperatures from 300 K to 400 K while altering the parameters of pulse interval, fluence, and the number of pulses with the absence of the external magnetic field. We observed accumulative all-optical switching at 380 K and above. Our observation of oxide NCO thin films facilitates the realization of chemically stable magnetization switching using ultrafast lasers, and without applying a magnetic field.
description: 6 pages, 6 figures
BV Ic CCD Observations of RR Lyrae variable SU Hor
Creators: name: V.V. Kravtsov
name: A.K. Dambis
name: A.Yu. Kniazev
name: L.N. Berdnikov
Publisher: name: Peremennye Zvezdy
Year: 2020

description: We present 3965 magnitude measurements in the B, V , and Ic filters acquired for the RR Lyrae star SU Hor. The star shows Blazhko effect.
Lower bounds for on-line graph colorings
Creators: name: Gutowski, Grzegorz
name: Kozik, Jakub
name: Micek, Piotr
name: Zhu, Xuding
Publisher: name: arXiv
Year: 2014
Subjects: subject: Combinatorics (math.CO)
subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: We propose two strategies for Presenter in on-line graph coloring games. The first one constructs bipartite graphs and forces any on-line coloring algorithm to use $2\log_2 n - 10$ colors, where $n$ is the number of vertices in the constructed graph. This is best possible up to an additive constant. The second strategy constructs graphs that contain neither $C_3$ nor $C_5$ as a subgraph and forces $Ω(\frac{n}{\log n}^\frac{1}{3})$ colors. The best known on-line coloring algorithm for these graphs uses $O(n^{\frac{1}{2}})$ colors.
The Coming Decades of Quantum Simulation
Creators: name: Fraxanet, Joana
name: Salamon, Tymoteusz
name: Lewenstein, Maciej
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Contemporary quantum technologies face major difficulties in fault tolerant quantum computing with error correction, and focus instead on various shades of quantum simulation (Noisy Intermediate Scale Quantum, NISQ) devices, analogue and digital quantum simulators and quantum annealers. There is a clear need and quest for such systems that, without necessarily simulating quantum dynamics of some physical systems, can generate massive, controllable, robust, entangled, and superposition states. This will, in particular, allow the control of decoherence, enabling the use of these states for quantum communications (e.g. to achieve efficient transfer of information in a safer and quicker way), quantum metrology, sensing and diagnostics (e.g. to precisely measure phase shifts of light fields, or to diagnose quantum materials). In this Chapter we present a vision of the golden future of quantum simulators in the decades to come.
New second derivative theories of gravity for spherically symmetric spacetimes
Creators: name: Tibrewala, Rakesh
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: We present new second derivative, generally covariant theories of gravity for spherically symmetric spacetimes (general covariance is in the $t-r$ plane) belonging to the class where the spherically symmetric Einstein-Hilbert theory is modified by the presence of $g_{θθ}$ dependent functions. In $3+1$ dimensional vacuum spacetimes there is three-fold infinity of freedom in constructing such theories as revealed by the presence of three arbitrary $g_{θθ}$ dependent functions in the Hamiltonian (matter Hamiltonian also has the corresponding freedom). This result is not a contradiction to the theorem of Hojman et. al. [1] which is applicable to the full theory whereas the above conclusion is for symmetry reduced sector of the theory (which has a much reduced phase space). In the full theory where there are no special symmetries, the result of Hojman et. al. will continue to hold. In the process we also show that theories where the constraint algebra is deformed by the presence of $g_{θθ}$ dependent functions - as is the case in the presence of inverse triad corrections in loop quantum gravity - can always be brought to the form where they obey the standard (undeformed) constraint algebra by performing a suitable canonical transformation. We prove that theories obtained after performing canonical transformation are inequivalent to the symmetry reduced general relativity and that the resulting theories fall within the purview of the theories mentioned above.
description: Significant changes made to the draft, title changed, conclusions remain unchanged. 24 pages
A classification of barycentrically associative polynomial functions
Creators: name: Marichal, Jean-Luc
name: Mathonet, Pierre
name: Tomaschek, Jörg
Publisher: name: arXiv
Year: 2014
Subjects: subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 13B25, 26B35, 39B72

description: We describe the class of polynomial functions which are barycentrically associative over an infinite commutative integral domain.
Gerrymandering Individual Fairness
Creators: name: Räz, Tim
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: Individual fairness, proposed by Dwork et al., is a fairness measure that is supposed to prevent the unfair treatment of individuals on the subgroup level, and to overcome the problem that group fairness measures are susceptible to manipulation, or gerrymandering. The goal of the present paper is to explore the extent to which it is possible to gerrymander individual fairness itself. It will be proved that gerrymandering individual fairness in the context of predicting scores is possible. It will also be argued that individual fairness provides a very weak notion of fairness for some choices of feature space and metric. Finally, it will be discussed how the general idea of individual fairness may be preserved by formulating a notion of fairness that allows us to overcome some of the problems with individual fairness identified here and elsewhere.
Vector Bundles associated to Monads on Cartesian Products of Projective Spaces
Creators: name: Maingi, Damian
Publisher: name: arXiv
Year: 2022
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14FO5, 14J60

description: In this paper we construct vector bundles associated to monads on $X=\mathbb{P}^n\times\mathbb{P}^n\times\mathbb{P}^m\times\mathbb{P}^m$. We first establish the existence of such monads on $X$. Once the monads exist, the next natural question is whether the cohomology vector bundle associated to these monads are simple or not. We study these vector bundles associated to monads and prove their stability and simplicity.
description: 12 pages
Transfer learning based physics-informed neural networks for solving inverse problems in engineering structures under different loading scenarios
Creators: name: Xu, Chen
name: Cao, Ba Trung
name: Yuan, Yong
name: Meschke, Günther
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Computer and information sciences

description: Recently, a class of machine learning methods called physics-informed neural networks (PINNs) has been proposed and gained prevalence in solving various scientific computing problems. This approach enables the solution of partial differential equations (PDEs) via embedding physical laws into the loss function. Many inverse problems can be tackled by simply combining the data from real life scenarios with existing PINN algorithms. In this paper, we present a multi-task learning method using uncertainty weighting to improve the training efficiency and accuracy of PINNs for inverse problems in linear elasticity and hyperelasticity. Furthermore, we demonstrate an application of PINNs to a practical inverse problem in structural analysis: prediction of external loads of diverse engineering structures based on limited displacement monitoring points. To this end, we first determine a simplified loading scenario at the offline stage. By setting unknown boundary conditions as learnable parameters, PINNs can predict the external loads with the support of measured data. When it comes to the online stage in real engineering projects, transfer learning is employed to fine-tune the pre-trained model from offline stage. Our results show that, even with noisy gappy data, satisfactory results can still be obtained from the PINN model due to the dual regularization of physics laws and prior knowledge, which exhibits better robustness compared to traditional analysis methods. Our approach is capable of bridging the gap between various structures with geometric scaling and under different loading scenarios, and the convergence of training is also greatly accelerated through not only the layer freezing but also the multi-task weight inheritance from pre-trained models, thus making it possible to be applied as surrogate models in actual engineering projects.
description: final version
Rigidity of 3D spherical caps via $μ$-bubbles
Creators: name: Hu, Yuhao
name: Liu, Peng
name: Shi, Yuguang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53C21, 53C24

description: By using Gromov's $μ$-bubble technique, we show that the $3$-dimensional spherical caps are rigid under perturbations that do not reduce the metric, the scalar curvature, and the mean curvature along its boundary. Several generalizations of this result will be discussed.
description: 20 pages, 1 figure, All comments are welcome