Results for "Martin Fuchs"

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A higher order TV-type variational problem related to the denoising and inpainting of imagesMar 27 2018We give a comprehensive survey on a class of higher order variational problems which are motivated by applications in mathematical imaging. The overall aim of this note is to investigate if and in which manner results from the first author's previous ... More
Liouville-type theorems for steady flows of degenerate power law fluids in the planeOct 15 2012We extend the Liouville-type theorems of Gilbarg and Weinberger and of Koch, Nadirashvili, Seregin and Sver\'ak valid for the stationary variant of the classical Navier-Stokes equations in 2D to the degenerate power law fluid model.
Ab initio pseudopotentials for electronic structure calculations of poly-atomic systems using density-functional theoryJul 31 1998The package fhi98PP allows one to generate norm-conserving pseudopotentials adapted to density-functional theory total-energy calculations for a multitude of elements throughout the periodic table, including first-row and transition metal elements. The ... More
A remark on the denoising of greyscale images using energy densities with varying growth ratesMar 28 2018We prove the solvability in Sobolev spaces for a class of variational problems related to the TV-model proposed by Rudin, Osher and Fatemi in [1] for the denoising of greyscale images. In contrast to their approach we discuss energy densities with variable ... More
A Liouville theorem for stationary incompressible fluids of von Mises typeMay 22 2018We consider entire solutions $u$ of the equations describing the stationary flow of a generalized Newtonian fluid in 2D concentrating on the question, if a Liouville-type result holds in the sense that the boundedness of $u$ implies its constancy. A positive ... More
Neutron Resonance Spin Flippers: Static Coils Manufactured by Electrical Discharge MachiningApr 14 2014Jul 11 2014Radiofrequency spin flippers (RFSF) are key elements of Neutron Resonance Spin Echo (NRSE) spectrometers, which allow performing controlled manipulations of the beam polarization. We report on the design and test of a new type of RFSF which originality ... More
Structural and conformational dynamics of supercooled polymer melts: Insights from first-principles theory and simulationsDec 05 2007We report on quantitative comparisons between simulation results of a bead-spring model and mode-coupling theory calculations for the structural and conformational dynamics of a supercooled, unentangled polymer melt. We find semiquantitative agreement ... More
Installing, Running and Maintaining Large Linux Clusters at CERNJun 12 2003Having built up Linux clusters to more than 1000 nodes over the past five years, we already have practical experience confronting some of the LHC scale computing challenges: scalability, automation, hardware diversity, security, and rolling OS upgrades. ... More
Recent progress constraining the nuclear equation of state from astrophysics and heavy ion reactionsJun 01 2007The quest for the nuclear equation of state (EoS) at high densities and/or extreme isospin is one of the longstanding problems of nuclear physics. Ab initio calculations for the nuclear many-body problem make predictions for the density and isospin dependence ... More
Discussion of: Statistical analysis of an archeological findApr 01 2008Discussion of ``Statistical analysis of an archeological find'' by Andrey Feuerverger [arXiv:0804.0079]
The Nuclear Equation of State at high densitiesOct 10 2006Ab inito calculations for the nuclear many-body problem make predictions for the density and isospin dependence of the nuclear equation-of-state (EOS) far away from the saturation point of nuclear matter. I compare predictions from microscopic and phenomenological ... More
The Relativistic Dirac-Brueckner Approach to Nuclear MatterSep 01 2003Sep 04 2003An overview on the relativistic Dirac-Brueckner approach to the nuclear many-body problem is given. Different approximation schemes are discussed, with particular emphasis on the nuclear self-energy and the saturation mechanism of nuclear matter. I will ... More
Strangeness production in heavy ion reactions at intermediate energiesDec 15 2003Mar 05 2004Kaon production, in particular $K^+$ production in heavy ion collisions at intermediate energies is discussed. Main emphasis is put on the question if subthreshold $K^+$ production can serve as a suitable tool to test the high density phase of such reactions ... More
The high density equation of state: constraints from accelerators and astrophysicsNov 21 2007The nuclear equation of state (EoS) at high densities and/or extreme isospin is one of the longstanding problems of nuclear physics. In the last years substantial progress has been made to constrain the EoS both, from the astrophysical side and from accelerator ... More
Kaon production in heavy ion reactions at intermediate energiesJul 07 2005Sep 01 2005The article reviews the physics related to kaon and antikaon production in heavy ion reactions at intermediate energies. Chiral dynamics predicts substantial modifications of the kaon properties in a dense nuclear environment. The status of the theoretical ... More
Enhanced light emission from top-emitting organic light-emitting diodes by optimizing surface plasmon polariton lossesMar 04 2015We demonstrate enhanced light extraction for monochrome top-emitting organic light-emitting diodes (OLEDs). The enhancement by a factor of 1.2 compared to a reference sample is caused by the use of a hole transport layer (HTL) material possessing a low ... More
A reciprocity principle for constrained isoperimetric problems and existence of isoperimetric subregions in convex setsMar 28 2018It is a well known fact that in $\mathbb{R}^n$ a subset of minimal perimeter $L$ among all sets of a given volume is also a set of maximal volume among all sets of the same perimeter $L$. This is called the reciprocity principle for isoperimetric problems. ... More
Neutron spin echo spectroscopy under 17T magnetic field at RESEDAJun 02 2014We report proof-of-principle measurements at the neutron resonance spin echo spectrometer RESEDA (MLZ) under large magnetic fields by means of Modulation of IntEnsity with Zero Effort (MIEZE). Our study demonstrates the feasibility of applying strong ... More
Signal recovery via TV-type energiesMar 28 2018We consider one-dimensional variants of the classical first order total variation denoising model introduced by Rudin, Osher and Fatemi. This study is based on our previous work on various denoising and inpainting problems in image analysis, where we ... More
Gain spectroscopy of a type-II VECSEL chipAug 18 2016Using optical pump-white light probe spectroscopy the gain dynamics is investigated for a VECSEL chip which is based on a type-II heterostructure. The active region the chip consists of a GaAs/(GaIn)As/Ga(AsSb)/(GaIn)As/GaAs multiple quantum well. For ... More
Consequences of kinetic non-equilibrium for the nuclear equation-of-state in heavy ion collisionNov 28 2002Dec 16 2002Highly compressed nuclear matter created in relativistic heavy collisions is to large extent governed by local non-equilibrium. As an idealized scenario colliding nuclear matter configurations are studied within both, relativistic mean field theory and ... More
Distinguishability and Accessible Information in Quantum TheoryJan 23 1996This document focuses on translating various information-theoretic measures of distinguishability for probability distributions into measures of distin- guishability for quantum states. These measures should have important appli- cations in quantum cryptography ... More
Delirium QuantumJun 10 2009This pseudo-paper consists of excerpts drawn from two of my quantum-email samizdats. Section 1 draws a picture of a physical world whose essence is ``Darwinism all the way down.'' Section 2 outlines how quantum theory should be viewed in light of this, ... More
Nuclear matter in the chiral limit and the in-medium chiral condensateOct 19 2007We investigate nuclear matter, i.e. the nuclear equation-of-state (EOS) as well as the relativistic mean fields in the chiral limit. The investigations are based on a chiral nucleon-nucleon EFT interaction where the explicit and implicit pion mass dependence ... More
Noise recovery for Lévy-driven CARMA processes and high-frequency behaviour of approximating Riemann sumsOct 04 2012Jan 31 2013We consider high-frequency sampled continuous-time autoregressive moving average (CARMA) models driven by finite-variance zero-mean L\'evy processes. An L^2-consistent estimator for the increments of the driving L\'evy process without order selection ... More
Copenhagen Interpretation Delenda Est?Sep 13 2018Nov 11 2018This is a slightly extended version of a review of Adam Becker's book What is Real? The Unfinished Quest for the Meaning of Quantum Physics, to appear in American Journal of Physics. The key addition is the reference list.
On Participatory RealismJan 17 2016Jun 28 2016In the Philosophical Investigations, Ludwig Wittgenstein wrote, " 'I' is not the name of a person, nor 'here' of a place, .... But they are connected with names. ... [And] it is characteristic of physics not to use these words." This statement expresses ... More
On the Quantumness of a Hilbert SpaceApr 21 2004We derive an exact expression for the quantumness of a Hilbert space (defined in quant-ph/0302092), and show that in composite Hilbert spaces the signal states must contain at least some entangled states in order to achieve such a sensitivity. Furthermore, ... More
Notwithstanding Bohr, the Reasons for QBismMay 09 2017Nov 11 2018Without Niels Bohr, QBism would be nothing. But QBism is not Bohr. This paper attempts to show that, despite a popular misconception, QBism is no minor tweak to Bohr's interpretation of quantum mechanics. It is something quite distinct. Along the way, ... More
Behavioral and Network Origins of Wealth Inequality: Insights from a Virtual WorldMar 25 2014Almost universally, wealth is not distributed uniformly within societies or economies. Even though wealth data have been collected in various forms for centuries, the origins for the observed wealth-disparity and social inequality are not yet fully understood. ... More
Interview with a Quantum BayesianJul 09 2012This paper collects into one place (most of) my answers to the questions Maximilian Schlosshauer posed in his interview volume, "Elegance and Enigma: The Quantum Interviews" (Springer, Frontiers Collection, 2011).
Density Dependent Hadron Field TheoryJul 28 1995A fully covariant approach to a density dependent hadron field theory is presented. The relation between in--medium NN interactions and field--theoretical meson--nucleon vertices is discussed. The medium dependence of nuclear interactions is described ... More
Composite polynomials in linear recurrence sequencesOct 29 2018Let $(G_n(x))_{n=0}^\infty$ be a $d$-th order linear recurrence sequence having polynomial characteristic roots, one of which has degree strictly greater than the others. Moreover, let $m\geq 2$ be a given integer. We ask for $n\in\mathbb{N}$ such that ... More
Bayesian Inference for Diffusion Processes: Using Higher-Order Approximations for Transition DensitiesJun 06 2018A powerful tool in many areas of science, diffusion processes model random dynamical systems in continuous time. Parameters can be estimated from time-discretely observed diffusion processes using Markov chain Monte Carlo (MCMC) methods that introduce ... More
Dilepton production in elementary and in heavy ion reactionsFeb 27 2004We present a unified description of the vector meson and dilepton production in elementary and in heavy ion reactions. The production of vector mesons ($\rho,\omega,\phi$) is described via the excitation of nucleon resonances ($R$). The theoretical framework ... More
Quantum Mechanics as Quantum Information (and only a little more)May 08 2002In this paper, I try once again to cause some good-natured trouble. The issue remains, when will we ever stop burdening the taxpayer with conferences devoted to the quantum foundations? The suspicion is expressed that no end will be in sight until a means ... More
The Anti-Vaxjo Interpretation of Quantum MechanicsApr 25 2002In this note, I try to accomplish two things. First, I fulfill Andrei Khrennikov's request that I comment on his "Vaxjo Interpretation of Quantum Mechanics," contrasting it with my own present view of the subject matter. Second, I try to paint an image ... More
Just Two Nonorthogonal Quantum StatesOct 12 1998From the perspective of quantum information theory, a system so simple as one restricted to just two nonorthogonal states can be surprisingly rich in physics. In this paper, we explore the extent of this statement through a review of three topics: (1) ... More
Information Gain vs. State Disturbance in Quantum TheoryNov 07 1996The engine that powers quantum cryptography is the principle that there are no physical means for gathering information about the identity of a quantum system's state (when it is known to be prepared in one of a set of nonorthogonal states) without disturbing ... More
$t$-perfection in near-bipartite and in $P_5$-free graphsJul 01 2015A graph is called $t$-perfect if its stable set polytope is fully described by non-negativity, edge and odd-cycle constraints. We characterise near-bipartite $t$-perfect and $P_5$-free $t$-perfect graphs in terms of forbidden $t$-minors. Moreover, we ... More
30 years of collaborationNov 24 2015We highlight some of the most important cornerstones of the long standing and very fruitful collaboration of the Austrian Diophantine Number Theory research group and the Number Theory and Cryptography School of Debrecen. However, we do not plan to be ... More
Quantum Measurement and the Paulian IdeaDec 13 2014Dec 16 2014In the quantum Bayesian (or QBist) conception of quantum theory, "quantum measurement" is understood not as a comparison of something pre-existent with a standard, but instead indicative of the creation of something new in the universe: Namely, the fresh ... More
QBism, the Perimeter of Quantum BayesianismMar 26 2010This article summarizes the Quantum Bayesian point of view of quantum mechanics, with special emphasis on the view's outer edges---dubbed QBism. QBism has its roots in personalist Bayesian probability theory, is crucially dependent upon the tools of quantum ... More
Quantum Bayesianism at the PerimeterMar 26 2010The author summarizes the Quantum Bayesian viewpoint of quantum mechanics, developed originally by C. M. Caves, R. Schack, and himself. It is a view crucially dependent upon the tools of quantum information theory. Work at the Perimeter Institute for ... More
The relativistic self-energy in nuclear dynamicsJul 26 2006It is a well known fact that Dirac phenomenology of nuclear forces predicts the existence of large scalar and vector mean fields in matter. To analyse the relativistic self-energy in a model independent way, modern high precision nucleon-nucleon ($NN$) ... More
Quantum Foundations in the Light of Quantum InformationJun 29 2001This paper reports three almost trivial theorems that nevertheless appear to have significant import for quantum foundations studies. 1) A Gleason-like derivation of the quantum probability law, but based on the positive operator-valued measures as the ... More
Softening of the nuclear equation-of-state by kinetic non-equilibrium in heavy ion collisionFeb 06 2001Highly compressed nuclear matter created in relativistic heavy collisions is to large extent governed by local non-equilibrium. As an idealised scenario colliding nuclear matter configurations are studied with an effective in-medium interaction based ... More
Information Gain vs. State Disturbance in Quantum TheoryMay 14 1996The engine that powers quantum cryptography is the principle that there are no physical means for gathering information about the identity of a quantum system's state (when it is known to be prepared in one of a set of nonorthogonal states) without disturbing ... More
Nonorthogonal Quantum States Maximize Classical Information CapacityMar 24 1997Aug 01 1997I demonstrate that, rather unexpectedly, there exist noisy quantum channels for which the optimal classical information transmission rate is achieved only by signaling alphabets consisting of nonorthogonal quantum states.
Unknown Quantum States and Operations, a Bayesian ViewApr 27 2004The classical de Finetti theorem provides an operational definition of the concept of an unknown probability in Bayesian probability theory, where probabilities are taken to be degrees of belief instead of objective states of nature. In this paper, we ... More
Pseudopotential study of binding properties of solids within generalized gradient approximations: The role of core-valence exchange-correlationJul 23 1997In ab initio pseudopotential calculations within density-functional theory the nonlinear exchange-correlation interaction between valence and core electrons is often treated linearly through the pseudopotential. We discuss the accuracy and limitations ... More
Existence Theory for the EED Inpainting ProblemJun 11 2019We establish an existence theory for an elliptic boundary value problem in image analysis known as edge-enhancing diffusion (EED) inpainting. The EED inpainting problem aims at restoring missing data in an image as steady state of a nonlinear anisotropic ... More
Quantum-Bayesian CoherenceJun 11 2009In a quantum-Bayesian take on quantum mechanics, the Born Rule cannot be interpreted as a rule for setting measurement-outcome probabilities from an objective quantum state. But if not, what is the role of the rule? In this paper, we argue that it should ... More
Optical properties of quantum wires: Disorder-scattering in the Lloyd-modelSep 25 2000The Lloyd model is extended to the exciton problem in quasi one-dimensional structures to study the interplay between the Coulomb attraction and disorder scattering. Within this model the averaging and resummation of the locator series can be performed ... More
On Kurzweil's 0-1 Law in Inhomogeneous Diophantine ApproximationJan 20 2015We give a sufficient and necessary condition such that for almost all $s\in{\mathbb R}$ \[ \|n\theta-s\|<\psi(n)\qquad\text{for infinitely many}\ n\in{\mathbb N}, \] where $\theta$ is fixed and $\psi(n)$ is a positive, non-increasing sequence. This improves ... More
On the solvability in Sobolev spaces and related regularity results for a variant of the TV-image recovery model: the vector-valued caseMar 27 2018We study classes of variational problems with energy densities of linear growth acting on vector-valued functions. Our energies are strictly convex variants of the TV-regularization model introduced by Rudin, Osher and Fatemi [15] as a powerful tool in ... More
Static Properties of a Simulated Supercooled Polymer Melt: Structure Factors, Monomer Distributions Relative to the Center of Mass, and Triple Correlation FunctionsFeb 25 2004We analyze structural and conformational properties in a simulated bead-spring model of a non-entangled, supercooled polymer melt. We explore the statics of the model via various structure factors, involving not only the monomers, but also the center ... More
Convex Regularization of Multi-Channel Images Based on Variants of the TV-ModelApr 04 2018We discuss existence and regularity results for multi-channel images in the setting of isotropic and anisotropic variants of the TV-model.
On the local boundedness of generalized minimizers of variational problems with linear growthApr 04 2018We prove local boundedness of generalized solutions to a large class of variational problems of linear growth including boundary value problems of minimal surface type and models from image analysis related to the procedure of TV-regularization occurring ... More
On Kendall's Tau for Order StatisticsAug 03 2018Every copula $ C $ for a random vector $ {\bf X}=(X_1,\dots,X_d) $ with identically distributed coordinates determines a unique copula $ C_{:d} $ for its order statistic $ {\bf X}_{:d}=(X_{1:d},\dots,X_{d:d}) $. In the present paper we study the dependence ... More
Quantum-Bayesian Coherence: The No-Nonsense VersionJan 15 2013In the Quantum-Bayesian interpretation of quantum theory (or QBism), the Born Rule cannot be interpreted as a rule for setting measurement-outcome probabilities from an objective quantum state. But if not, what is the role of the rule? In this paper, ... More
Modelization of the EOSNov 25 2005May 24 2006This article summarizes theoretical predictions for the density and isospin dependence of the nuclear mean field and the corresponding nuclear equation of state. We compare predictions from microscopic and phenomenological approaches. An application to ... More
QBism and the Greeks: why a quantum state does not represent an element of physical realityDec 13 2014May 11 2015In QBism (or Quantum Bayesianism) a quantum state does not represent an element of physical reality but an agent's personal probability assignments, reflecting his subjective degrees of belief about the future content of his experience. In this paper, ... More
Squeezing Quantum Information through a Classical Channel: Measuring the "Quantumness" of a Set of Quantum StatesFeb 11 2003Jul 29 2003In this paper we propose a general method to quantify how "quantum" a set of quantum states is. The idea is to gauge the quantumness of the set by the worst-case difficulty of transmitting the states through a purely classical communication channel. Potential ... More
The $p$-adic analytic subgroup theorem revisitedFeb 03 2015It is well-known that the W\"ustholz' analytic subgroup theorem is one of the most powerful theorems in transcendence theory. The theorem gives in a very systematic and conceptual way the transcendence of a large class of complex numbers, e.g. the transcendence ... More
The Quantumness of a Set of Quantum StatesFeb 13 2003This article is an introduction to quant-ph/0302092. We propose to quantify how "quantum" a set of quantum states is. The quantumness of a set is the worst-case difficulty of transmitting the states through a classical communication channel. Potential ... More
Dependence between Path-length and Size in Random Digital TreesJan 10 2017We study the size and the external path length of random tries and show that they are asymptotically independent in the asymmetric case but strongly dependent with small periodic fluctuations in the symmetric case. Such an unexpected behavior is in sharp ... More
Dependence between External Path-Length and Size in Random TriesApr 29 2016May 06 2016We study the size and the external path length of random tries and show that they are asymptotically independent in the asymmetric case but strongly dependent with small periodic fluctuations in the symmetric case. Such an unexpected behavior is in sharp ... More
Estimators for a Class of Bivariate Measures of Concordance for CopulasJan 17 2017In the present paper we propose and study estimators for a wide class of bivariate measures of concordance for copulas. These measures of concordance are generated by a copula and generalize Spearman's rho and Gini's gamma. In the case of Spearman's rho ... More
Some applications of the $p$-adic analytic subgroup theoremDec 03 2014Jan 11 2016We use a $p$-adic analogue of the analytic subgroup theorem of W\"ustholz to deduce the transcendence and linear independence of some new classes of $p$-adic numbers. In particular we give $p$-adic analogues of results of W\"ustholz contained in [G. W\"ustholz, ... More
Commutative algebraic groups and $p$-adic linear formsApr 16 2014Jan 20 2016Let $G$ be a commutative algebraic group defined over a number field $K$ that is disjoint over $K$ to $\mathbb G_a$ and satisfies the condition of semistability. Consider a linear form $l$ on the Lie algebra of $G$ with algebraic coefficients and an algebraic ... More
Bayesian Conditioning, the Reflection Principle, and Quantum DecoherenceMar 30 2011The probabilities a Bayesian agent assigns to a set of events typically change with time, for instance when the agent updates them in the light of new data. In this paper we address the question of how an agent's probabilities at different times are constrained ... More
A Quantum-Bayesian Route to Quantum-State SpaceDec 21 2009In the quantum-Bayesian approach to quantum foundations, a quantum state is viewed as an expression of an agent's personalist Bayesian degrees of belief, or probabilities, concerning the results of measurements. These probabilities obey the usual probability ... More
Priors in quantum Bayesian inferenceJun 09 2009In quantum Bayesian inference problems, any conclusions drawn from a finite number of measurements depend not only on the outcomes of the measurements but also on a prior. Here we show that, in general, the prior remains important even in the limit of ... More
Information Tradeoff Relations for Finite-Strength Quantum MeasurementsSep 25 2000In this paper we give a new way to quantify the folklore notion that quantum measurements bring a disturbance to the system being measured. We consider two observers who initially assign identical mixed-state density operators to a two-state quantum system. ... More
Quantum State Disturbance vs. Information Gain: Uncertainty Relations for Quantum InformationDec 22 1995When an observer wants to identify a quantum state, which is known to be one of a given set of non-orthogonal states, the act of observation causes a disturbance to that state. We investigate the tradeoff between the information gain and that disturbance. ... More
Parton rearrangement and fast thermalization in heavy-ion collisions at RHIC and LHC energiesMay 26 2008The implications of parton rearrangement processes on the dynamics of ultra-relativistic heavy-ion collisions have been investigated. A microscopic transport approach, namely the quark gluon string model (QGSM) which has been extended for a locally density-dependent ... More
Asymmetric Colliding Nuclear Matter Approach in Heavy Ion CollisionsJun 01 2004The early stage of a heavy ion collision is governed by local non-equilibrium momentum distributions which have been approximated by colliding nuclear matter configurations, i.e. by two Lorentz elongated Fermi ellipsoids. This approach has been extended ... More
The Quantum State of an Ideal Propagating Laser FieldApr 08 2001Dec 05 2001We give a quantum information-theoretic description of an ideal propagating CW laser field and reinterpret typical quantum-optical experiments in light of this. In particular we show that contrary to recent claims [T. Rudolph and B. C. Sanders, Phys. ... More
Dirac Structure of the Nucleus-Nucleus Potential in Heavy Ion CollisionsDec 01 1998We investigate nuclear matter properties in the relativistic Brueckner approach. The in-medium on-shell T-matrix is represented covariantly by five Lorentz invariant amplitudes from which we deduce directly the nucleon self-energy. To enforce correct ... More
Notes on a Paulian Idea: Foundational, Historical, Anecdotal and Forward-Looking Thoughts on the QuantumMay 09 2001This document is the first installment of three in the Cerro Grande Fire Series. It is a collection of letters written to various colleagues, most of whom regularly circuit this archive, including Howard Barnum, Paul Benioff, Charles Bennett, Herbert ... More
Optical absorption in semiconductor quantum dots: Nonlocal effectsOct 19 2000Nov 09 2001The optical absorption of a single spherical semiconductor quantum dot in an electrical field is studied taking into account the nonlocal coupling between the field of the light and the polarizability of the semiconductor. These nonlocal effects lead ... More
Thermodynamical description of heavy ion collisionsSep 11 2000We analyze the thermodynamical state of nuclear matter in transport descriptions of heavy ion reactions. We determine thermodynamical variables from an analysis of local momentum space distributions and compare to blast model parameters from an analysis ... More
Spectator and participant decay in heavy ion collisionsMay 07 1999Mar 01 2000We analyze the thermodynamical state of nuclear matter in transport calculations of heavy--ion reactions. In particular we determine temperatures and radial flow parameters from an analysis of fragment energy spectra and compare to local microscopic temperatures ... More
Nucleon self-energy in the relativistic Brueckner approachJan 29 1997May 02 1997The formalism of the relativistic (or Dirac-) Brueckner approach in infinite nuclear matter is described. As nucleon-nucleon interaction the one-boson exchange potentials Bonn A,B,C and for comparison the Walecka model are used. The T-matrix is determined ... More
QBism: Quantum Theory as a Hero's HandbookDec 21 2016Jan 16 2017This paper represents an elaboration of the lectures delivered by one of us (CAF) during "Course 197 -- Foundations of Quantum Physics" at the International School of Physics "Enrico Fermi" in Varenna, Italy, July 2016. Much of the material for it is ... More
Diophantine triples in linear recurrence sequences of Pisot typeNov 10 2017The study of Diophantine triples taking values in linear recurrence sequences is a variant of a problem going back to Diophantus of Alexandria which has been studied quite a lot in the past. The main questions are, as usual, about existence or finiteness ... More
Local-global principles in circle packingsJul 20 2017Aug 07 2017We generalize work of Bourgain-Kontorovich and Zhang, proving an almost local-to-global property for the curvatures of certain circle packings, to a large class of Kleinian groups. Specifically, we associate in a natural way an infinite family of integral ... More
An analytic approach to the asymptotic variance of trie statistics and related structuresMar 18 2013Apr 15 2013We develop analytic tools for the asymptotics of general trie statistics, which are particularly advantageous for clarifying the asymptotic variance. Many concrete examples are discussed for which new Fourier expansions are given. The tools are also useful ... More
On completely decomposable and separable modules over Prüfer domainsDec 02 2011We generalize known results on summands of completely decomposable and separable torsion-free abelian groups to modules over h-local Pr\"ufer domains. Over such domains summands of completely decomposable torsion-free modules are again completely decomposable ... More
Quantum information: How much information in a state vector?Jan 25 1996Quantum information refers to the distinctive information-processing properties of quantum systems, which arise when information is stored in or retrieved from nonorthogonal quantum states. More information is required to prepare an ensemble of nonorthogonal ... More
The Quantum State of a Propagating Laser FieldNov 29 2001Optical implementations of quantum communication protocols typically involve laser fields. However, the standard description of the quantum state of a laser field is surprisingly insufficient to understand the quantum nature of such implementations. In ... More
Fragment Formation and Phase Transitions in Heavy Ion CollisionsMar 20 2000We investigate the thermodynamical properties of nuclear matter in heavy ion collisions, in particular with respect to questions of thermodynamical instability, phase transitions and fragmentation. For this we analyze results of relativistic transport ... More
Non-Equilibrium and Collective Flow Effects in Relativistic Heavy Ion CollisionsDec 04 2002We discuss the problems involved in extracting the nuclear equation-of-state from heavy-ion collisions. We demonstrate that the equation of state becomes effectively softer in non-equilibrium and this effect is observable in terms of collective flow effects. ... More
Reaching Consensus Among Mobile Agents: A Distributed Protocol for the Detection of Social SituationsSep 29 2014Physical social encounters are governed by a set of socio-psychological behavioral rules with a high degree of uniform validity. Past research has shown how these rules or the resulting properties of the encounters (e.g. the geometry of interaction) can ... More
Low densities in asymmetric nuclear matterJul 03 2007Sep 20 2007Asymmetric nuclear matter is investigated in the low density region below the nuclear saturation density. Microscopic calculations based on the Dirac Brueckner Hartree-Fock (DBHF) approach with realistic nucleon-nucleon potentials are used to adjust a ... More
Semiclassical expansion of quantum characteristics for many-body potential scattering problemMay 06 2006May 15 2007In quantum mechanics, systems can be described in phase space in terms of the Wigner function and the star-product operation. Quantum characteristics, which appear in the Heisenberg picture as the Weyl's symbols of operators of canonical coordinates and ... More
SS 433 : a phenomenon imitating a Wolf-Rayet starDec 07 2005We present mid-infrared (2-12 micron) spectra of the microquasar SS 433 obtained with the Infrared Space Observatory (spectroscopic mode of ISOPHOT and ISOCAM). We compare them to the spectra of four Wolf-Rayet stars: WR78, WR134, WR136, and WR147 in ... More
A 2.4-80 micron spectrophotometric study of SS433 with ISODec 14 2001We present ISOPHOT spectrophotometric observations of SS433 at four different orbital phases in 1996 and 1997. The HeI+HeII lines in both spectra of SS433 and the Wolf-Rayet star WR147, a WN8+BO5 binary system, closely match. The 2.5-12 micron continuum ... More
Markov chain analysis of random walks on disordered mediumNov 12 1993We study the dynamical exponents $d_{w}$ and $d_{s}$ for a particle diffusing in a disordered medium (modeled by a percolation cluster), from the regime of extreme disorder (i.e., when the percolation cluster is a fractal at $p=p_{c}$) to the Lorentz ... More