Results for "Fritz Körmann"

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Ab initio vibrational free energies including anharmonicity for multicomponent alloysFeb 28 2019A density-functional-theory based approach to efficiently compute numerically exact vibrational free energies - including anharmonicity - for chemically complex multicomponent alloys is developed. It is based on a combination of thermodynamic integration ... More
Impact of local lattice relaxations on phase stability and chemical ordering in bcc NbMoTaW high-entropy alloys explored by ab initio based machine-learning potentialsOct 25 2018Recently, high-entropy alloys (HEAs) attracted wide attention due to their extraordinary materials properties. A main challenge in identifying new HEAs is the lack of efficient approaches for exploring their huge compositional space. Ab initio calculations ... More
Temperature-dependent phonon spectra of magnetic random solid solutionsFeb 08 2017A first-principles-based method for computing phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed. The method takes fluctuations of force constants (FCs) due to magnetic excitations as well as due to chemical ... More
Anomalous phonon lifetime shortening in paramagnetic CrN caused by magneto-lattice coupling: A combined spin and ab initio molecular dynamics studyFeb 08 2018We study the mutual coupling of spin fluctuations and lattice vibrations in paramagnetic CrN by combining atomistic spin dynamics and ab initio molecular dynamics. The two degrees of freedom are dynamically coupled leading to non-adiabatic effects. Those ... More
Structural stability and thermodynamics of CrN magnetic phases from ab initio and experimentAug 14 2014The dynamical and thermodynamic phase stabilities of the stoichiometric compound CrN including different structural and magnetic configurations are comprehensively investigated using a first-principles density-functional-theory (DFT) plus U approach in ... More
Nonlocality with less ComplementarityJun 20 2011Feb 01 2012In quantum mechanics, nonlocality (a violation of a Bell inequality) is intimately linked to complementarity, by which we mean that consistently assigning values to different observables at the same time is not possible. Nonlocality can only occur when ... More
Beyond Bell's Theorem: Correlation ScenariosJun 22 2012Sep 02 2012Bell's Theorem witnesses that the predictions of quantum theory cannot be reproduced by theories of local hidden variables in which observers can choose their measurements independently of the source. Working out an idea of Branciard, Rosset, Gisin and ... More
Laser Cooling of TeV MuonsJul 20 2000We show that Compton scattering can be used to cool TeV-scale muon beams, and we derive analytical expressions for the equilibrium transverse angular spread, longitudinal energy spread, and power requirements. We find that a factor of a few thousand reduction ... More
Towards a Re-definition of the Second Based on Optical Atomic ClocksJan 09 2015Jan 28 2015The rapid increase in accuracy and stability of optical atomic clocks compared to the caesium atomic clock as primary standard of time and frequency asks for a future re-definition of the second in the International System of Units (SI). The status of ... More
Intensional Constructed Numbers: Towards Formalizing the Notion of AlgorithmSep 25 2017This work is meant to be a step towards the formal definition of the notion of algorithm, in the sense of an equivalence class of programs working "in a similar way". But instead of defining equivalence transformations directly on programs, we look at ... More
B+ and B0 Mean Lifetime MeasurementsSep 19 1994We review $B^+$ and $B^0$ mean lifetime measurements, including direct measurements and determination of the lifetime ratio via measurements of the ratio of branching ratios. We present world averages.
$B$ Physics with the CDF Run II UpgradeDec 21 1995We summarize Run I results relevant to an analysis of the CP asymmetry in $B\to J/\psi K_s$, the CDF upgrade plans for Run II, and some of the main $B$ physics goals related to the exploration of the origin of CP violation.
Quantum-Critical transport at a semimetal-to-insulator transition on the honeycomb latticeDec 01 2010Jan 25 2012In this paper we study transport properties of electrons on the two-dimensional honeycomb lattice. We consider a half-filled system in the vicinity of a symmetry-breaking transition from a semimetallic phase towards an insulating phase with either charge ... More
On the computation of harmonic maps by unconstrained algorithms based on totally geodesic embeddingsOct 17 2016In this paper, we present an algorithm for the computation of harmonic maps, and respectively, of the harmonic map heat flow between two closed Riemannian manifolds. Our approach is based on the totally geodesic embedding of the target manifold into $\mathbb{R}^N$ ... More
Generalized automorphic sheaves and the proportionality principle of Hirzebruch-MumfordMar 14 2016We axiomatize the algebraic structure of toroidal compactifications of Shimura varieties and their automorphic vector bundles. We propose a notion of generalized automorphic sheaf which includes the sheaves of sections of automorphic vector bundles with ... More
Inverse spectral theory as influenced by Barry SimonFeb 02 2010We survey Barry Simon's principal contributions to the field of inverse spectral theory in connection with one-dimensional Schrodinger and Jacobi operators.
Tsirelson's problem and Kirchberg's conjectureAug 06 2010May 04 2012Tsirelson's problem asks whether the set of nonlocal quantum correlations with a tensor product structure for the Hilbert space coincides with the one where only commutativity between observables located at different sites is assumed. Here it is shown ... More
Descent for coherent sheaves along formal/open coveringsMar 07 2016For a regular noetherian scheme $X$ with a divisor with strict normal crossings $D$ we prove that coherent sheaves satisfy descent w.r.t. the 'covering' consisting of the open parts in the various completions of $X$ along the components of $D$ and their ... More
Quantum analogues of Hardy's nonlocality paradoxJun 12 2010Apr 04 2011Hardy's nonlocality is a "nonlocality proof without inequalities": it exemplifies that quantum correlations can be qualitatively stronger than classical correlations. This paper introduces variants of Hardy's nonlocality in the CHSH scenario which are ... More
Quantum correlations in the temporal CHSH scenarioMay 19 2010Mar 26 2014We consider a temporal version of the CHSH scenario using projective measurements on a single quantum system. It is known that quantum correlations in this scenario are fundamentally more general than correlations obtainable with the assumptions of macroscopic ... More
On the existence of quantum representations for two dichotomic measurementsAug 18 2009Feb 16 2010Under which conditions do outcome probabilities of measurements possess a quantum-mechanical model? This kind of problem is solved here for the case of two dichotomic von Neumann measurements which can be applied repeatedly to a quantum system with trivial ... More
Long Baseline Neutrino Physics: From Fermilab to KamiokaMar 03 2002We have investigated the physics potential of very long baseline experiments designed to measure nu_mu to nu_e oscillation probabilities. The principles of our design are to tune the beam spectrum to the resonance energy for the matter effect, and to ... More
On infinite-dimensional state spacesFeb 16 2012Apr 26 2013It is well-known that the canonical commutation relation $[x,p]=i$ can be realized only on an infinite-dimensional Hilbert space. While any finite set of experimental data can also be explained in terms of a finite-dimensional Hilbert space by approximating ... More
From Sazonov's Non-Dcpo Natural Domains to Closed Directed-Lub Partial OrdersMay 06 2016Normann proved that the domains of the game model of PCF (the domains of sequential functionals) need not be dcpos. Sazonov has defined natural domains for a theory of such incomplete domains. This paper further develops that theory. It defines lub-rules ... More
Full Abstraction for a Recursively Typed Lambda Calculus with Parallel ConditionalJun 11 2008We define the syntax and reduction relation of a recursively typed lambda calculus with a parallel case-function (a parallel conditional). The reduction is shown to be confluent. We interpret the recursive types as information systems in a restricted ... More
Transition probabilities and measurement statistics of postselected ensemblesMar 23 2010Jul 20 2010It is well-known that a quantum measurement can enhance the transition probability between two quantum states. Such a measurement operates after preparation of the initial state and before postselecting for the final state. Here we analyze this kind of ... More
Antisymmetry of the stochastic order on all ordered metric spacesOct 16 2018In this short note, we prove that the stochastic order of Radon probability measures on any metric space is antisymmetric.
Quantum logic is undecidableJul 20 2016Nov 04 2016We investigate the first-order theory of closed subspaces of complex Hilbert spaces in the signature $(\lor,\perp,0,1)$, where `$\perp$' is the orthogonality relation. Our main result is that already its purely implicational fragment is undecidable: there ... More
Polyhedral duality in Bell scenarios with two binary observablesFeb 01 2012Jun 18 2012For the Bell scenario with two parties and two binary observables per party, it is known that the no-signaling polytope is the polyhedral dual (polar) of the Bell polytope. Computational evidence suggests that this duality also holds for three parties. ... More
Fibered Multiderivators and (co)homological descentMay 05 2015Nov 24 2015The theory of derivators enhances and simplifies the theory of triangulated categories. In this article a notion of fibered (multi-)derivator is developed, which similarly enhances fibrations of (monoidal) triangulated categories. We present a theory ... More
Six Functor Formalisms and Fibered MultiderivatorsMar 07 2016We define abstract six-functor-formalisms using the theory of (op)fibrations of 2-multicategories. We also give axioms for a Wirthm\"uller and Grothendieck formalism (where either $f_!=f_*$ or $f^!=f^*$) or intermediate formalisms (where we have e.g. ... More
Beyond Bell's Theorem II: Scenarios with arbitrary causal structureApr 18 2014Aug 10 2015It has recently been found that Bell scenarios are only a small subclass of interesting setups for studying the non-classical features of quantum theory within spacetime. We find that it is possible to talk about classical correlations, quantum correlations ... More
The dynamics of a charged particleApr 29 2008Using physical arguments, I derive the physically correct equations of motion for a classical charged particle from the Lorentz-Abraham-Dirac equations (LAD) which are well known to be physically incorrect. Since a charged particle can classically not ... More
Quantum logic is undecidableJul 20 2016We investigate the first-order theory of closed subspaces of complex Hilbert spaces in the signature $(\lor,\perp,0)$, where `$\perp$' is orthogonality. Our main result is that already its purely implicational fragment is undecidable: there is no algorithm ... More
On Berry's conjectures about the stable order in PCFAug 02 2011Oct 11 2012PCF is a sequential simply typed lambda calculus language. There is a unique order-extensional fully abstract cpo model of PCF, built up from equivalence classes of terms. In 1979, G\'erard Berry defined the stable order in this model and proved that ... More
A unified construction of semiring-homomorphic graph invariantsJan 04 2019Jan 22 2019It has recently been observed by Zuiddam that finite graphs form a preordered commutative semiring under the graph homomorphism preorder together with join and disjunctive product as addition and multiplication, respectively. This led to a new characterization ... More
The geometric and arithmetic volume of Shimura varieties of orthogonal typeMay 26 2011We apply the theory of Borcherds products to calculate arithmetic volumes (heights) of Shimura varieties of orthogonal type up to contributions from very bad primes. The approach is analogous to the well-known computation of their geometric volume by ... More
On recursive properties of certain p-adic Whittaker functionsOct 05 2010We investigate recursive properties of certain p-adic Whittaker functions (of which representation densities of quadratic forms are special values). The proven relations can be used to compute them explicitly in arbitrary dimensions, provided that enough ... More
Categories of Fractions RevisitedMar 18 2008Sep 16 2011The theory of categories of fractions as originally developed by Gabriel and Zisman is reviewed in a pedagogical manner giving detailed proofs of all statements. A weakening of the category of fractions axioms used by Higson is discussed and shown to ... More
Notes on Triangulated CategoriesJul 14 2014Jul 16 2014We give an elementary introduction to the theory of triangulated categories covering their axioms, homological algebra in triangulated categories, triangulated subcategories, and Verdier localization. We try to use a minimal set of axioms for triangulated ... More
Invariance entropy, quasi-stationary measures and control setsMay 24 2017Nov 27 2017For control systems in discrete time, this paper discusses measure-theoretic invariance entropy for a subset Q of the state space with respect to a quasi-stationary measure obtained by endowing the control range with a probability measure. The main results ... More
A generalization of Strassen's Positivstellensatz and its application to large deviation theoryOct 19 2018Jan 04 2019Strassen's Positivstellensatz is a powerful but little known theorem on preordered commutative semirings satisfying a boundedness condition similar to Archimedeanicity. It characterizes the relaxed preorder induced by all monotone homomorphisms to $\mathbb{R}_+$ ... More
Derivator Six Functor Formalisms --- Definition and Construction IJan 09 2017Jul 17 2017A theory of a derivator version of six-functor-formalisms is developed, using an extension of the notion of fibered multiderivator due to the author. Using the language of (op)fibrations of 2-multicategories this has (like a usual fibered multiderivator) ... More
Enlargement of (fibered) derivatorsJun 29 2017We show that the theory of derivators (or, more generally, of fibered multiderivators) on all small categories is equivalent to this theory on partially ordered sets, in the following sense: Every derivator (more generally, every fibered multiderivator) ... More
Operator system structures on the unital direct sum of C*-algebrasNov 04 2010Feb 09 2012This work is motivated by Radulescu's result on the comparison of C*-tensor norms on C*(F_n) x C*(F_n). For unital C*-algebras A and B, there are natural inclusions of A and B into their unital free product, their maximal tensor product and their minimal ... More
Unconventional Ideas for Axion and Dark Matter ExperimentsSep 26 2015In this contribution an entirely different way compared to conventional approaches for axion, hidden photon and dark matter (DM) detection is proposed for discussion. The idea is to use living plants which are known to be very sensitive to all kind of ... More
Distance Measurements and Stellar Population Properties via Surface Brightness FluctuationsMay 07 2012Surface Brightness Fluctuations (SBFs) are one of the most powerful techniques to measure the distance and to constrain the unresolved stellar content of extragalactic systems. For a given bandpass, the absolute SBF magnitude \bar{M} depends on the properties ... More
Integrable Systems in the Infinite Genus LimitJul 07 1999We provide an elementary approach to integrable systems associated with hyperelliptic curves of infinite genus. In particular, we explore the extent to which the classical Burchnall-Chaundy theory generalizes in the infinite genus limit, and systematically ... More
Generalized automorphic sheaves and the proportionality principle of Hirzebruch-MumfordMar 14 2016Jun 05 2019We axiomatize the algebraic properties of toroidal compactifications of (mixed) Shimura varieties and their automorphic vector bundles. A notion of generalized automorphic sheaf is proposed which includes sheaves of (meromorphic) sections of automorphic ... More
Differentiable equivalence of fractional linear mapsAug 10 2006A Moebius system is an ergodic fibred system $(B,T)$ (see \citer5) defined on an interval $B=[a,b]$ with partition $(J_k),k\in I,#I\geq 2$ such that $Tx=\frac{c_k+d_kx}{a_k+b_kx}$, $x\in J_k$ and $T|_{J_k}$ is a bijective map from $J_k$ onto $B$. It is ... More
Curious properties of hypergraph C*-algebrasAug 28 2018Oct 17 2018Given a finite hypergraph $H$, the associated hypergraph C*-algebra $C^*(H)$ is finitely presented by one projection for each vertex of $H$, such that each hyperedge forms a partition of unity. General hypergraph C*-algebras were first studied in the ... More
Velocity Polytopes of Periodic Graphs and a No-Go Theorem for Digital PhysicsSep 09 2011Jun 17 2013A periodic graph in dimension $d$ is a directed graph with a free action of $\Z^d$ with only finitely many orbits. It can conveniently be represented in terms of an associated finite graph with weights in $\Z^d$, corresponding to a $\Z^d$-bundle with ... More
A presentation of the category of stochastic matricesFeb 16 2009Mar 31 2009This note gives generators and relations for the strict monoidal category of probabilistic maps on finite cardinals (i.e., stochastic matrices).
Resource convertibility and ordered commutative monoidsApr 14 2015Jul 02 2015Resources and their use and consumption form a central part of our life. Many branches of science and engineering are concerned with the question of which given resource objects can be converted into which target resource objects. For example, information ... More
Convex Spaces I: Definition and ExamplesMar 31 2009Oct 19 2015We propose an abstract definition of convex spaces as sets where one can take convex combinations in a consistent way. A priori, a convex space is an algebra over a finitary version of the Giry monad. We identify the corresponding Lawvere theory as the ... More
Six Functor Formalisms and Fibered MultiderivatorsMar 07 2016Feb 28 2017We develop the theory of (op)fibrations of 2-multicategories and use it to define abstract six-functor-formalisms. We also give axioms for Wirthm\"uller and Grothendieck formalisms (where either $f^!=f^*$ or $f_!=f_*$) or intermediate formalisms where ... More
Derivator Six-Functor-Formalisms - Construction IIFeb 10 2019Starting from very simple and obviously necessary axioms on a (derivator enhanced) four-functor-formalism, we construct derivator six-functor-formalisms using compactifications. This works, for example, for various contexts over topological spaces and ... More
The Concept of an Emergent Cosmographic VacuumJul 10 2009Mar 12 2010The argument for an "Emergent Cosmographic Vacuum" state which generates fermion and weak boson masses is outlined. Its limitations and its consequences are discussed. Predictions for LHC are presented.
Central Baryons in Dual Models and the Possibility of a Backward Peak in DiffractionFeb 17 2000Mar 09 2000Two distinct interactions of Pomerons should occur in dense multi-string events. Besides the usual triple Pomeron processes transitions to membraned cylinders can be expected to contribute in a significant way. They offer an efficient mechanism for central ... More
Baryon Transport in Dual Models and the Possibility of a Backward Peak in DiffractionJan 17 2001Dual string models contain significant baryon transfers and seem essentially consistent with the available data. We here turn to a careful consideration of the relevant topological structures. The baryon transfer is associated with one of two possible ... More
Linear Representations of the Automorphism Group of a Free GroupJun 08 2006Let $F_n$ be the free group on $n\ge 2$ elements and $\A(F_n)$ its group of automorphisms. In this paper we present a rich collection of linear representations of $\A(F_n)$ arising through the action of finite index subgroups of it on relation modules ... More
Generating Optimal Plans in Highly-Dynamic DomainsMay 09 2012Generating optimal plans in highly dynamic environments is challenging. Plans are predicated on an assumed initial state, but this state can change unexpectedly during plan generation, potentially invalidating the planning effort. In this paper we make ... More
Weyl-Titchmarsh M-Function Asymptotics, Local Uniqueness Results, Trace Formulas, and Borg-type Theorems for Dirac OperatorsFeb 06 2001We explicitly determine the high-energy asymptotics for Weyl-Titchmarsh matrices associated with general Dirac-type operators on half-lines and on $\bbR$. We also prove new local uniqueness results for Dirac-type operators in terms of exponentially small ... More
Monads, partial evaluations, and rewritingOct 14 2018Monads can be interpreted as encoding formal expressions, or formal operations in the sense of universal algebra. We give a construction which formalizes the idea of "evaluating an expression partially": for example, "2+3" can be obtained as a partial ... More
A Probability Monad as the Colimit of Finite PowersDec 14 2017Nov 27 2018We define and study a probability monad on the category of complete metric spaces and short maps. It assigns to each space the space of Radon probability measures on it with finite first moment, equipped with the Kantorovich-Wasserstein distance. This ... More
Spin-liquid phase and order-by-disorder of classical Heisenberg spins on the swedenborgite latticeApr 07 2014Frustration refers to the inability to satisfy competing interactions simultaneously, often leading to a large number of degenerate ground states. This can suppress ordering tendencies, sometimes resulting in a spin liquid phase. An intrinsic effect lifting ... More
Quadratic sequences of powers and Mohanty's ConjectureOct 17 2016We prove under the Bombieri-Lang conjecture for surfaces that there is an absolute bound on the length of sequences of integer squares with constant second differences, for sequences which are not formed by the squares of integers in arithmetic progression. ... More
Derivation of the Leroux system as the hydrodynamic limit of a two-component lattice gasApr 29 2003May 13 2003The long time behavior of a couple of interacting asymmetric exclusion processes of opposite velocities is investigated in one space dimension. We do not allow two particles at the same site, and a collision effect (exchange) takes place when particles ... More
Spectral Properties of a Class of Reflectionless Schrödinger OperatorsMar 03 2006We prove that one-dimensional reflectionless Schr\"odinger operators with spectrum a homogeneous set in the sense of Carleson, belonging to the class introduced by Sodin and Yuditskii, have purely absolutely continuous spectra. This class includes all ... More
On Spectral Theory for Schrödinger Operators with Strongly Singular PotentialsMay 06 2005Jul 27 2010We examine two kinds of spectral theoretic situations: First, we recall the case of self-adjoint half-line Schr\"odinger operators on [a,\infty), a\in\bbR, with a regular finite end point a and the case of Schr\"odinger operators on the real line with ... More
A Multi-World Approach to Question Answering about Real-World Scenes based on Uncertain InputOct 01 2014May 05 2015We propose a method for automatically answering questions about images by bringing together recent advances from natural language processing and computer vision. We combine discrete reasoning with uncertain predictions by a multi-world approach that represents ... More
Self-averaging characteristics of spectral fluctuationsOct 20 2014The spectral form factor as well as the two-point correlator of the density of (quasi-)energy levels of individual quantum dynamics are not self-averaging. Only suitable smoothing turns them into useful characteristics of spectra. We present numerical ... More
On (conditional) positive semidefiniteness in a matrix-valued contextFeb 01 2016Jan 23 2017In a nutshell, we intend to extend Schoenberg's classical theorem connecting conditionally positive semidefinite functions $F\colon \mathbb{R}^n \to \mathbb{C}$, $n \in \mathbb{N}$, and their positive semidefinite exponentials $\exp(tF)$, $t > 0$, to ... More
Modification of the Lifshitz-Kosevich formula for anomalous quantum oscillations in inverted insulatorsApr 21 2017It is generally believed that quantum oscillations are a hallmark of a Fermi surface and the oscillations constitute the ringing of it. Recently, it was understood that in order to have well defined quantum oscillations you do not only not need well defined ... More
An Abstract Approach to Weak Convergence of Spectral Shift Functions and Applications to Multi-Dimensional Schrödinger OperatorsNov 01 2011We study the manner in which a sequence of spectral shift functions $\xi(\cdot;H_j,H_{0,j})$ associated with abstract pairs of self-adjoint operators $(H_j, H_{0,j})$ in Hilbert spaces $\cH_j$, $j\in\bbN$, converge to a limiting spectral shift function ... More
Factorizations and Hardy-Rellich-Type InequalitiesJan 31 2017Apr 14 2017The principal aim of this note is to illustrate how factorizations of singular, even-order partial differential operators yield an elementary approach to classical inequalities of Hardy-Rellich-type. More precisly, introducing the two-parameter $n$-dimensional ... More
A Borg-Type Theorem Associated with Orthogonal Polynomials on the Unit CircleJan 14 2005We prove a general Borg-type result for reflectionless unitary Cantero-Moral-Velazquez (CMV) operators U associated with orthogonal polynomials on the unit circle. The spectrum of U is assumed to be a connected arc on the unit circle. This extends a recent ... More
A Jost-Pais-type reduction of (modified) Fredholm determinants for semi-separable operators in infinite dimensionsApr 03 2014Aug 29 2014We study the analog of semi-separable integral kernels in $\mathcal{H}$ of the type $$ K(x,x')=\begin{cases} F_1(x)G_1(x'), & a<x'< x< b, \\ F_2(x)G_2(x'), & a<x<x'<b, \end{cases} $$ where $-\infty\leq a<b\leq \infty$, and for a.e.\ $x \in (a,b)$, $F_j ... More
Nonlocal Robin Laplacians and some remarks on a paper by Filonov on eigenvalue inequalitiesDec 10 2008Feb 03 2010The aim of this paper is twofold: First, we characterize an essentially optimal class of boundary operators $\Theta$ which give rise to self-adjoint Laplacians $-\Delta_{\Theta, \Omega}$ in $L^2(\Omega; d^n x)$ with (nonlocal and local) Robin-type boundary ... More
Nonadiabatic transitions between adiabatic surfaces: phase diffusion in superconducting atomic point contactsJun 03 2009Motivated by experiments with current biased superconducting atomic point contacts the general problem of nonadiabatic transitions between adiabatic surfaces in presence of strong dissipation is studied. For a single channel device the supercurrent is ... More
A Model with a Cosmographic LandscapeFeb 16 2007To argue against a too narrow focus in the LHC Higgs search, a simpleminded model with a rich "cosmographic" vacuum structure for the generation of masses is developed on a conceptual level. In this framework Higgs like bosons which could exist in the ... More
Phase transitions in the pseudogap Anderson and Kondo models: Critical dimensions, renormalization group, and local-moment criticalityAug 26 2004Jan 03 2005The pseudogap Kondo problem, describing quantum impurities coupled to fermionic quasiparticles with a pseudogap density of states, rho(omega) ~ |omega|^r, shows a rich zero-temperature phase diagram, with different screened and free moment phases and ... More
Is a Rich Vacuum Structure Responsible for Fermion and Weak-Boson MassesMar 06 2009An unconventional Cosmographical model for a generation of fermion and week boson masses without electro-weak Higgs bosons is outlined. It is based on a rich, non perturbative vacuum structure taken to be an object of qualitative phenomenology. Numerous ... More
FGS Astrometry with the Hubble Space TelescopeJul 05 2000This article describes astrometric science that can be done with the Hubble Space Telescope Fine Guidance Sensors and presents some recent science results. We outline how these data are modeled, acquired, and calibrated. We next show how the astrometer, ... More
Semiclassical spectra from periodic-orbit clusters in a mixed phase spaceMar 25 1997We determine semiclassical quasienergy spectra from periodic orbits for a system with a mixed phase space, the kicked top. Throughout the transition from integrability to well developed chaos the standard error incurred for the quasienergies is a small ... More
NN Correlations and Relativistic Hartree Fock in Finite NucleiSep 28 1993Two different approximation schemes for the self-consistent solution of the relativistic Brueckner-Hartree-Fock equation for finite nuclei are discussed using realistic One-Boson-Exchange potentials. In a first scheme, the effects of correlations are ... More
Connectedness of the Isospectral Manifold for One-Dimensional Half-Line Schrödinger OperatorsJul 01 2003Let V_0 be a real-valued function on [0,\infty) and V\in L^1([0,R]) for all R>0 so that H(V_0)= -\f{d^2}{dx^2}+V_0 in L^2([0,\infty)) with u(0)=0 boundary conditions has discrete spectrum bounded from below. Let \calM (V_0) be the set of V so that H(V) ... More
Quantum chaos and effective thermalizationOct 06 2011Mar 21 2012We demonstrate effective equilibration for unitary quantum dynamics under conditions of classical chaos. Focusing on the paradigmatic example of the Dicke model, we show how a constructive description of the thermalization process is facilitated by the ... More
Lyapunov exponents for random continuous-time switched systems and stabilizabilityNov 20 2015For linear systems in continuous time with random switching, the Lyapunov exponents are characterized using the Multiplicative Ergodic Theorem for an associated system in discrete time. An application to control systems shows that here a controllability ... More
Mid-infrared frequency comb spanning an octave based on an Er fiber laser and difference-frequency generationFeb 27 2012Mar 22 2012We describe a coherent mid-infrared continuum source with 700 cm-1 usable bandwidth, readily tuned within 600 - 2500 cm-1 (4 - 17 \mum) and thus covering much of the infrared "fingerprint" molecular vibration region. It is based on nonlinear frequency ... More
The Physics of Kondo Impurities in GrapheneAug 15 2012Feb 15 2013This article summarizes our understanding of the Kondo effect in graphene, primarily from a theoretical perspective. We shall describe different ways to create magnetic moments in graphene, either by adatom deposition or via defects. For dilute moments, ... More
Renormalized oscillation theory for Hamiltonian systemsAug 06 2016We extend a result on renormalized oscillation theory, originally derived for Sturm-Liouville and Dirac-type operators on arbitrary intervals in the context of scalar coefficients, to the case of general Hamiltonian systems with block matrix coefficients. ... More
Emission temperatures and freeze out densities from light particle correlation functions in Au+Au collisions at 1 A GeVApr 03 1997A study of emission temperatures extracted from excited state populations and of freeze out radii from light particle intensity interferometry is presented. Three high resolution dE-E-Hodoscopes with a total of 216 detectors are combined with the ALADiN ... More
(Almost) C*-algebras as sheaves with self-actionDec 05 2015Sep 08 2016Via Gelfand duality, a unital C*-algebra $A$ induces a functor from compact Hausdorff spaces to sets, $\mathsf{CHaus}\to\mathsf{Set}$. We show how this functor encodes standard functional calculus in $A$ as well as its multivariate generalization. Certain ... More
An entropic approach to local realism and noncontextualityJan 16 2012Jan 30 2012For any Bell locality scenario (or Kochen-Specker noncontextuality scenario), the joint Shannon entropies of local (or noncontextual) models define a convex cone for which the non-trivial facets are tight entropic Bell (or contextuality) inequalities. ... More
The antiferromagnetic Ising model on the swedenborgite latticeJun 05 2014Geometrical frustration in spin systems often results in a large number of degenerate ground states. In this work we study the antiferromagnetic Ising model on the three dimensional swedenborgite lattice which is a specific stacking of Kagom\'e and triangular ... More
On subgroup conjugacy separability in the class of virtually free groupsDec 22 2010A group G is called subgroup conjugacy separable (abbreviated as SCS), if any two finitely generated and non-conjugate subgroups of G remain non-conjugate in some finite quotient of G. We prove that the free groups and the fundamental groups of finite ... More
On Self-adjoint and J-self-adjoint Dirac-type Operators: A Case StudyNov 15 2005Nov 30 2005We provide a comparative treatment of some aspects of spectral theory for self-adjoint and non-self-adjoint (but J-self-adjoint) Dirac-type operators connected with the defocusing and focusing nonlinear Schr\"odinger equation, of relevance to nonlinear ... More
Stochastic order on metric spaces and the ordered Kantorovich monadAug 29 2018In earlier work, we had introduced the Kantorovich probability monad on complete metric spaces, extending a construction due to van Breugel. Here we extend the Kantorovich monad further to a certain class of ordered metric spaces, by endowing the spaces ... More
Bimonoidal Structure of Probability MonadsApr 10 2018Aug 22 2018We give a conceptual treatment of the notion of joints, marginals, and independence in the setting of categorical probability. This is achieved by endowing the usual probability monads (like the Giry monad) with a monoidal and an opmonoidal structure, ... More