Results for "Daniel Hexner"

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Noise, diffusion, and hyperuniformityNov 08 2016We consider driven many-particle models which have a phase transition between an active and an absorbing phase. Like previously studied models, we have particle conservation, but here we introduce an additional symmetry - when two particles interact, ... More
Self Organization and Self Avoiding Limit CyclesJan 05 2014A simple periodically driven system displaying rich behavior is introduced and studied. The system self-organizes into a mosaic of static ordered regions with three possible patterns, which are threaded by one-dimensional paths on which a small number ... More
Hyperuniformity of critical absorbing statesJul 01 2014Aug 24 2014The properties of the absorbing states of non-equilibrium models belonging to the conserved directed percolation universality class are studied. We find that at the critical point the absorbing states are hyperuniform, exhibiting anomalously small density ... More
Tug-of-war in motility assay experimentsMar 02 2009The dynamics of two groups of molecular motors pulling in opposite directions on a rigid filament is studied theoretically. To this end we first consider the behavior of one set of motors pulling in a single direction against an external force using a ... More
Entropic commensurate-incommensurate transitionNov 29 2012Jan 26 2013The equilibrium properties of a minimal tiling model are investigated. The model has extensive ground state entropy, with each ground state having a quasiperiodic sequence of rows. It is found that the transition from the quasiperiodic ground state to ... More
Can a large packing be assembled from smaller ones?Feb 02 2019We consider zero temperature packings of soft spheres, that undergo a jamming to unjamming transition as a function of packing fraction. We compare differences in the structure, as measured from the contact statistics, of a finite subsystem of a large ... More
Directed aging, memory and Nature's greedMar 14 2019Disordered materials are often out of equilibrium and evolve very slowly. This allows a memory of the imposed strains or preparation conditions to be encoded in the material. Here we consider "directed aging", where the elastic properties of a material ... More
Linking microscopic and macroscopic response in disordered solidsJun 19 2017The modulus of a rigid network of harmonic springs depends on the sum of the energies in each of the bonds due to the applied distortion: compression in the case of the bulk modulus, $B$, or shear in the case of the shear modulus, $\mathcal{G}$. The distortion ... More
Two diverging length scales in the structure of jammed packingsOct 19 2017Jun 11 2018At densities higher than the jamming transition for athermal, frictionless repulsive spheres we find two distinct length scales, both of which diverge as a power law as the transition is approached. The first, $\xi_{Z}$, is associated with the two-point ... More
Role of local response in manipulating the elastic properties of disordered solids by bond removalAug 23 2017We explore the range over which the elasticity of disordered spring networks can be manipulated by the removal of selected bonds. By taking into account the local response of a bond, we demonstrate that the effectiveness of pruning can be improved so ... More
Amorphous topological insulators constructed from random point setsDec 29 2016Oct 09 2018The discovery that the band structure of electronic insulators may be topologically non-trivial has unveiled distinct phases of electronic matter with novel properties. Recently, mechanical lattices have been found to have similarly rich structure in ... More
An Extended Kalman Filter with a Computed Mean Square Error BoundOct 01 2014The paper proposes a new recursive filter for non-linear systems that inherently computes a valid bound on the mean square estimation error. The proposed filter, bound based extended Kalman, (BEKF) is in the form of an extended Kalman filter. The main ... More
Equilateral Non-Gaussianity and New Physics on the HorizonFeb 25 2011Mar 23 2011We examine the effective theory of single-field inflation in the limit where the scalar perturbations propagate with a small speed of sound. In this case the non-linearly realized time-translation symmetry of the Lagrangian implies large interactions, ... More
Natural symmetric tensor normsFeb 22 2010Dec 14 2010In the spirit of the work of Grothendieck, we introduce and study natural symmetric n-fold tensor norms. We prove that there are exactly six natural symmetric tensor norms for $n\ge 3$, a noteworthy difference with the 2-fold case in which there are four. ... More
Five basic lemmas for symmetric tensor products of normed spacesMay 18 2011We give the symmetric version of five lemmas which are essential for the theory of tensor products (and norms). These are: the approximation, extension, embedding, density and local technique lemmas. Some application of these tools to the metric theory ... More
Scaling Laws in Self-Gravitating DisksApr 16 1999The interstellar medium (ISM) reveals strongly inhomogeneous structures at every scale. These structures do not seem completely random since they obey certain power laws. Larson's law (\citeyear{Larson81}) $\sigma \propto R^{\delta}$ and the plausible ... More
Supergravity for Effective TheoriesSep 01 2011Higher-derivative operators are central elements of any effective field theory. In supersymmetric theories, these operators include terms with derivatives in the K\"ahler potential. We develop a toolkit for coupling such supersymmetric effective field ... More
Inflating with BaryonsSep 15 2010We present a field theory solution to the eta problem. By making the inflaton field the phase of a baryon of SU(N_c) supersymmetric Yang-Mills theory we show that all operators that usually spoil the flatness of the inflationary potential are absent. ... More
Casimir force in O(n) lattice models with a diffuse interfaceJun 23 2008On the example of the spherical model we study, as a function of the temperature $T$, the behavior of the Casimir force in O(n) systems with a diffuse interface and slab geometry $\infty^{d-1}\times L$, where $2<d<4$ is the dimensionality of the system. ... More
Fragmentation in Kinematically Cold DisksJan 16 2001Gravity is scale free. Thus gravity may form similar structures in self-gravitating systems on different scales. Indeed, observations of the interstellar medium, spiral disks and cosmic structures, reveal similar characteristics. The structures in these ... More
A Field Range Bound for General Single-Field InflationNov 13 2011We explore the consequences of a detection of primordial tensor fluctuations for general single-field models of inflation. Using the effective theory of inflation, we propose a generalization of the Lyth bound. Our bound applies to all single-field models ... More
Extending polynomials in maximal and minimal idealsOct 20 2009Feb 08 2010Given an homogeneous polynomial on a Banach space $E$ belonging to some maximal or minimal polynomial ideal, we consider its iterated extension to an ultrapower of $E$ and prove that this extension remains in the ideal and has the same ideal norm. As ... More
Unconditionality in tensor products and ideals of polynomials, multilinear forms and operatorsJun 17 2009Feb 08 2010We study tensor norms that destroy unconditionality in the following sense: for every Banach space $E$ with unconditional basis, the $n$-fold tensor product of $E$ (with the corresponding tensor norm) does not have unconditional basis. We establish an ... More
Formalizing and Checking Thread Refinement for Data-Race-Free Execution Models (Extended Version)Oct 24 2015When optimizing a thread in a concurrent program (either done manually or by the compiler), it must be guaranteed that the resulting thread is a refinement of the original thread. Most theories of valid optimizations are formulated in terms of valid syntactic ... More
Desensitizing Inflation from the Planck ScaleApr 21 2010A new mechanism to control Planck-scale corrections to the inflationary eta parameter is proposed. A common approach to the eta problem is to impose a shift symmetry on the inflaton field. However, this symmetry has to remain unbroken by Planck-scale ... More
Signatures of Supersymmetry from the Early UniverseSep 01 2011Oct 11 2011Supersymmetry plays a fundamental role in the radiative stability of many inflationary models. Spontaneous breaking of the symmetry inevitably leads to fields with masses of order the Hubble scale during inflation. When these fields couple to the inflaton ... More
The symmetric Radon-Nikodým property for tensor normsMay 15 2010We introduce the symmetric-Radon-Nikod\'ym property (sRN property) for finitely generated s-tensor norms $\beta$ of order $n$ and prove a Lewis type theorem for s-tensor norms with this property. As a consequence, if $\beta$ is a projective s-tensor norm ... More
A note on some fiber-integralsDec 22 2015We remark that the study of a fiber-integral of the type F (s) := f =s ($\omega$/df) $\land$ ($\omega$/df) either in the local case where $\rho$ $\not\equiv$ 1 around 0 is C $\infty$ and compactly supported near the origin which is a singular point of ... More
Quasi-proper meromorphic equivalence relationsJun 02 2010The aim of this article is to complete results of [M.00] and [B.08] and to show that they imply a rather general existence theorem for meromorphic quotient of strongly quasi-proper meromorphic equivalence relations. In this context, generic equivalence ... More
A finiteness theorem for \ $S-$relative formal Brieskorn modulesJul 17 2012Mar 01 2014We give a general result of finiteness for holomorphic families of Brieskorn modules constructed from a holomorphic family of one parameter degeneration of compact complex manifolds acquiring (general) singularities.
Asymptotics of a vanishing period : the quotient themes of a given frescoJan 20 2011In this paper we introduce the word "fresco" to denote a $[\lambda]-$primitive monogenic geometric (a,b)-module. The study of this "basic object" (generalized Brieskorn module with one generator) which corresponds to the minimal filtered (regular) differential ... More
Sur certaines singularites non isolees d'hypersurfaces IMay 19 2005Jan 09 2006The aim of this fisrt part is to introduce, for a rather large class of hypersurface singularities with 1 dimensionnal locus, the analog of the Brieskorn lattice at the origin (the singular point of the singular locus). The main results are the finitness ... More
Design, Evaluation and Analysis of Combinatorial Optimization Heuristic AlgorithmsJul 07 2012Combinatorial optimization is widely applied in a number of areas nowadays. Unfortunately, many combinatorial optimization problems are NP-hard which usually means that they are unsolvable in practice. However, it is often unnecessary to have an exact ... More
Quantifying Residual Finiteness of Linear GroupsFeb 15 2016Feb 27 2016Normal residual finiteness growth measures how well a finitely generated group is approximated by its finite quotients. We show that any linear group $\Gamma \leq \mathrm{GL}_d(K)$ has normal residual finiteness growth asymptotically bounded above by ... More
$\mathfrak{sl}_n$-webs, categorification and Khovanov-Rozansky homologiesApr 23 2014Jul 21 2014In this paper we define an explicit basis for the $\mathfrak{sl}_n$-web algebra $H_n(\vec{k})$, the $\mathfrak{sl}_n$ generalization of Khovanov's arc algebra $H_{2}(m)$, using categorified $q$-skew Howe duality. Our construction is a $\mathfrak{sl}_n$-web ... More
$\mathfrak{sl}_3$-web bases, intermediate crystal bases and categorificationOct 10 2013Mar 05 2014We give an explicit graded cellular basis of the $\mathfrak{sl}_3$-web algebra $K_S$. In order to do this, we identify Kuperberg's basis for the $\mathfrak{sl}_3$-web space $W_S$ with a version of Leclerc-Toffin's intermediate crystal basis and we identify ... More
Virtual Khovanov homology using cobordismsNov 02 2011Sep 02 2014We extend Bar-Natan's cobordism based categorification of the Jones polynomial to virtual links. Our topological complex allows a direct extension of the classical Khovanov complex ($h=t=0$), the variant of Lee ($h=0,t=1$) and other classical link homologies. ... More
Categorification and applications in topology and representation theoryJul 03 2013This thesis splits into two major parts. The connection between the two parts is the notion of "categorification" which we shortly explain/recall in the introduction. In the first part of this thesis we extend Bar-Natan's cobordism based categorification ... More
Asteroseismology of Cool StarsNov 04 2014The measurement of oscillations excited by surface convection is a powerful method to study the structure and evolution of cool stars. CoRoT and Kepler have initiated a revolution in asteroseismology by detecting oscillations in thousands of stars from ... More
Fault-Tolerant Quantum ComputationJan 16 2007Aug 30 2007I give a brief overview of fault-tolerant quantum computation, with an emphasis on recent work and open questions.
Universal 2-local Hamiltonian Quantum ComputingFeb 02 2010Nov 21 2011We present a Hamiltonian quantum computation scheme universal for quantum computation (BQP). Our Hamiltonian is a sum of a polynomial number (in the number of gates L in the quantum circuit) of time-independent, constant-norm, 2-local qubit-qubit interaction ... More
Complex bounds for multimodal maps: bounded combinatoricsSep 19 2000Sep 19 2000We proved the so called complex bounds for multimodal, infinitely renormalizable analytic maps with bounded combinatorics: deep renormalizations have polynomial-like extensions with definite modulus. The complex bounds is the first step to extend the ... More
Overview of TMD evolutionFeb 03 2015Transverse momentum dependent parton distributions (TMDs) appear in many scattering processes at high energy, from the semi-inclusive DIS experiments at a few GeV to the Higgs transverse momentum distribution at the LHC. Predictions for TMD observables ... More
TMD evolution of the Sivers asymmetryApr 19 2013The energy scale dependence of the Sivers asymmetry in semi-inclusive deep inelastic scattering is studied numerically within the framework of TMD factorization that was put forward in 2011. The comparison to previous results in the literature shows that ... More
Transversity AsymmetriesAug 21 2008Ways to access transversity through asymmetry measurements are reviewed. The recent first extraction and possible near future extractions are discussed.
Review of QCD spin physicsMay 27 2003A short review is given of QCD spin physics and its major aims: obtaining the polarized gluon density, the transversity distribution and understanding single spin asymmetries. The importance of the Drell-Yan process, the role of electron-positron colliders ... More
Average transverse momentum quantities approaching the lightfrontSep 29 2014In this contribution to Light Cone 2014, three average transverse momentum quantities are discussed: the Sivers shift, the dijet imbalance, and the $p_T$ broadening. The definitions of these quantities involve integrals over all transverse momenta that ... More
Anomalous Drell-Yan asymmetry from hadronic or QCD vacuum effectsNov 03 2005The anomalously large cos(2 phi) asymmetry measured in the Drell-Yan process is discussed. Possible origins of this large deviation from the Lam-Tung relation are considered with emphasis on the comparison of two particular proposals: one that suggests ... More
Mapping the Transverse Nucleon SpinJun 24 2002Jul 23 2002The transverse nucleon spin can be transferred to the quarks and gluons in several ways. In the factorizing, hard scattering processes to be considered, these are parameterized at leading twist by the transversity distribution function and at next-to-leading ... More
Double transverse spin asymmetries in vector boson productionApr 24 2000Sep 09 2000We investigate a helicity non-flip double transverse spin asymmetry in vector boson production in hadron-hadron scattering, which was first considered by Ralston and Soper at the tree level. It does not involve transversity functions and in principle ... More
Intrinsic transverse momentum and transverse spin asymmetriesMay 13 1999We investigate leading twist transverse momentum dependent origins of transverse spin asymmetries in hadron-hadron collisions. The chiral-odd T-odd distribution function with intrinsic transverse momentum dependence, which would signal an intrinsic handedness ... More
On a theorem of Bombieri, Friedlander and IwaniecAug 01 2011In this article, we show to which extent one can improve a theorem of Bombieri, Friedlander and Iwaniec by using Hooley's variant of the divisor switching technique. We also give an application of the theorem in question, which is a Bombieri-Vinogradov ... More
Composition of Kinetic Momenta: The U_q(sl(2)) caseDec 10 1992Mar 29 1993The tensor products of (restricted and unrestricted) finite dimensional irreducible representations of $\uq$ are considered for $q$ a root of unity. They are decomposed into direct sums of irreducible and/or indecomposable representations.
Analyticity in Hubbard modelsOct 23 1998Feb 11 1999The Hubbard model describes a lattice system of quantum particles with local (on-site) interactions. Its free energy is analytic when \beta t is small, or \beta t^2/U is small; here, \beta is the inverse temperature, U the on-site repulsion and t the ... More
The relation between Feynman cycles and off-diagonal long-range orderMar 31 2006Aug 23 2006The usual order parameter for the Bose-Einstein condensation involves the off-diagonal correlation function of Penrose and Onsager, but an alternative is Feynman's notion of infinite cycles. We present a formula that relates both order parameters. We ... More
A Hsu-Robbins-Erdős strong law in first-passage percolationMay 27 2013Sep 09 2015Large deviations in the context of first-passage percolation was first studied in the early 1980s by Grimmett and Kesten, and has since been revisited in a variety of studies. However, none of these studies provides a precise relation between the existence ... More
Erratum to the paper: Compact hyperkaehler manifolds: basic resultsJun 03 2001This is an Erratum to the paper: Compact hyperkaehler manifolds: basic results. (alg-geom/9705025, Inv. math. 135). We give a correct proof of the projectivity criterion for hyperkaehler manifolds. We use a recent result of Demailly and Paun math.AG/0105176. ... More
A note on the Bloch-Beilinson conjecture for K3 surfaces and spherical objectsSep 22 2010For a projective K3 surface X we introduce the dense triangulated subcategory S^* of the bounded derived category D^b(Coh(X)) of coherent sheaves on X that is generated by spherical objects. For a K3 surface X over \bar Q it is shown that S^* admits a ... More
Chow groups and derived categories of K3 surfacesDec 29 2009This survey is based on my talk at the conference `Classical algebraic geometry today' at the MSRI. Some new results on the action of symplectomorphisms on the Chow group are added.
Charged String-like Solutions of Low-energy Heterotic String TheoryOct 06 1992Two string-like solutions to the equations of motion of the low-energy effective action for the heterotic string are found, each a source of electric and magnetic fields. The first carries an electric current equal to the electric charge per unit length ... More
Vertical flows and a general currential homotopy formulaMay 05 2014We generalize some of the results of Harvey, Lawson and Latschev about transgression formulas. The focus here is on flowing forms via vertical vector fields, especially Morse-Bott-Smale vector fields. We prove a very general transgression formula including ... More
Parity Types, Cycle Structures and Autotopisms of Latin SquaresMar 01 2012Oct 03 2012The parity type of a Latin square is defined in terms of the numbers of even and odd rows and columns. It is related to an Alon-Tarsi-like conjecture that applies to Latin squares of odd order. Parity types are used to derive upper bounds for the size ... More
Dynamics of warped flux compactifications with backreacting anti-branesFeb 19 2014May 06 2014We revisit the effective low-energy dynamics of the volume modulus in warped flux compactifications with anti-D3-branes in order to analyze the prospects for meta-stable de Sitter vacua and brane inflation along the lines of KKLT/KKLMMT. At the level ... More
Factorizations of Elements in Noncommutative Rings: A SurveyJul 27 2015May 30 2016We survey results on factorizations of non zero-divisors into atoms (irreducible elements) in noncommutative rings. The point of view in this survey is motivated by the commutative theory of non-unique factorizations. Topics covered include unique factorization ... More
Distributed Computing Concepts in D0Oct 16 2003The D0 experiment faces many challenges enabling access to large datasets for physicists on four continents. The new concepts for distributed large scale computing implemented in D0 aim for an optimal use of the available computing resources while minimising ... More
On the computation of zone and double zone diagramsAug 14 2012Apr 29 2013Classical objects in computational geometry are defined by explicit relations. A few years ago an interesting family of geometric objects defined by implicit relations was introduced in the pioneering works of T. Asano, J. Matousek and T. Tokuyama. An ... More
A derivation of the beam equationDec 03 2015The Euler-Bernoulli equation describing the deflection of a beam is a vital tool in structural and mechanical engineering. However, its derivation usually entails a number of intermediate steps that may confuse engineering or science students at the beginnig ... More
Solution of the Dicke model for N=3Apr 09 2013The N=3 Dicke model couples three qubits to a single radiation mode via dipole interaction and constitutes the simplest quantum-optical system allowing for Greenberger-Horne-Zeilinger states. In contrast to the case N=1 (the Rabi model), it is non-integrable ... More
Tuner: a tool for designing and optimizing ion optical systemsSep 29 2011Designing and optimizing ion optical systems is often a complex and difficult task, which requires the use of computational tools to iterate and converge towards the desired characteristics and performances of the system. Very often these tools are not ... More
Proof of the cases $p \leq 7$ of the Lieb-Seiringer formulation of the Bessis-Moussa-Villani conjectureFeb 08 2007Mar 13 2007It is shown that the polynomial $\lambda(t) = {\rm Tr}[(A + tB)^p]$ has nonnegative coefficients when $p \leq 7$ and A and B are any two complex positive semidefinite $n \times n$ matrices with arbitrary $n$. This proofs a general nontrivial case of the ... More
Rapid multiperiodic variability in a high-mass X-ray binaryJul 29 2004Positions of High-Mass X-ray Binaries are often known precisely enough to unambiguously identify the optical component, and a number of those stars are monitored by the OGLE and MACHO collaborations. The light curves of two such candidates are examined ... More
Superparticle Signatures: from PAMELA to the LHCAug 26 2009Oct 02 2009Signatures of soft supersymmetry breaking at the CERN LHC and in dark matter experiments are discussed with focus drawn to light superparticles, and in particular light gauginos and their discovery prospects. Connected to the above is the recent PAMELA ... More
The Lanczos potential as a spin-2 fieldNov 20 2003The Lanczos potential $L_{abc}$ acts as a tensor potential for the spin-2 field strength $W_{abcd}$ in an role similar to that of the vector potential $A_a$ for the Maxwell tensor $F_{ab}$. After some general considerations inspired by the example of ... More
Upper limits on the probability of an interstellar civilization arising in the local Solar neighborhoodJan 22 2015At this point in time, there is very little empirical evidence on the likelihood of a space-faring species originating in the biosphere of a habitable world. However, there is a tension between the expectation that such a probability is relatively high ... More
Exploration of the local solar neighborhood I: Fixed number of probesApr 01 2013Previous work in studying interstellar exploration by one or several probes has focused primarily either on engineering models for a spacecraft targeting a single star system, or large-scale simulations to ascertain the time required for a civilization ... More
Large-Scale Structure and Future SurveysJan 30 2003As the 2dF Galaxy Redshift Survey and Sloan Digital Sky Survey move toward completion, it is time to ask what the next generation of survey of large-scale structure should be. I discuss some of the cosmological justifications for such surveys and conclude ... More
An algorithm for evaluating Gram matrices in Verma modules of W-algebrasDec 02 2014Aug 18 2015I present a simple dynamic programming algorithm for the evaluation of operators in a wide range of superconformal algebras. Special care is taken to describe the computation of the Gram matrix. A Mathematica package, Weaver.m, is provided that implements ... More
On conformal supergravity and harmonic superspaceAug 31 2015Sep 01 2015This paper describes a fully covariant approach to harmonic superspace. It is based on the conformal superspace description of conformal supergravity and involves extending the supermanifold M^{4|8} by the tangent bundle of CP^1. The resulting superspace ... More
Conserved supercurrents and Fayet-Iliopoulos terms in supergravityMar 01 2010Mar 03 2010Recently there has appeared in the literature a sequence of papers questioning the consistency of supergravity coupled to Fayet-Iliopoulos terms. A key feature of these arguments is a demonstration that the conventional superspace stress tensor fails ... More
A Formalism and an Algorithm for Computing Pragmatic Inferences and Detecting InfelicitiesApr 26 1995Apr 26 1995Since Austin introduced the term ``infelicity'', the linguistic literature has been flooded with its use, but no formal or computational explanation has been given for it. This thesis provides one for those infelicities that occur when a pragmatic inference ... More
Theoretical Properties of the Overlapping Groups LassoMar 23 2011Nov 09 2011We present two sets of theoretical results on the grouped lasso with overlap of Jacob, Obozinski and Vert (2009) in the linear regression setting. This method allows for joint selection of predictors in sparse regression, allowing for complex structured ... More
Precision Measurements of the Top Quark Mass at the TevatronMay 25 2006We report precision measurements of the top quark mass using events collected by the D{\O}and CDF II detectors from $p\bar{p}$ collisions at $\sqrt s = 1.96$ TeV at the Fermilab Tevatron. Measurements are presented in multiple decay channels. In addition, ... More
Remarks on the Cauchy functional equation and variations of itFeb 19 2010Aug 03 2016This paper examines various aspects related to the Cauchy functional equation $f(x+y)=f(x)+f(y)$, a fundamental equation in the theory of functional equations. In particular, it considers its solvability and its stability relative to subsets of multi-dimensional ... More
A constructive proof presenting languages in $Σ_2^P$ that cannot be decided by circuit families of size $n^k$Aug 27 2014Sep 17 2014As far as I know, at the time that I originally devised this result (1998), this was the first constructive proof that, for any integer $k$, there is a language in $\Sigma_2^P$ that cannot be simulated by a family of logic circuits of size $n^k$. However, ... More
Jerusalem Lectures on Black Holes and Quantum InformationSep 03 2014Sep 24 2015In these lectures I give an introduction to the quantum physics of black holes, including recent developments based on quantum information theory such as the firewall paradox and its various cousins. I also give an introduction to holography and the AdS/CFT ... More
The Madelung transform as a momentum mapDec 15 2015Apr 13 2016The Madelung transform relates the non-linear Schr\"odinger equation and a compressible Euler equation known as the quantum hydrodynamical system. We prove that the Madelung transform is a momentum map associated with an action of the semidirect product ... More
Parameter estimation with mixed quantum statesFeb 05 2010We consider quantum enhanced measurements with initially mixed states. We show very generally that for any linear propagation of the initial state that depends smoothly on the parameter to be estimated, the sensitivity is bound by the maximal sensitivity ... More
A simpel and versatile cold-atom simulator of non-Abelian gauge potentialsFeb 05 2010We show how a single, harmonically trapped atom in a tailored magnetic field can be used for simulating the effects of a broad class of non-abelian gauge potentials. We demonstrate how to implement Rashba or Linear-Dresselhaus couplings, or observe {\em ... More
Quantum Chaos and Quantum AlgorithmsOct 05 2001It was recently shown (quant-ph/9909074) that parasitic random interactions between the qubits in a quantum computer can induce quantum chaos and put into question the operability of a quantum computer. In this work I investigate whether already the interactions ... More
Dissipative Chaotic Quantum Maps: Expectation Values, Correlation Functions and the Invariant StateOct 07 1999Oct 11 1999I investigate the propagator of the Wigner function for a dissipative chaotic quantum map. I show that a small amount of dissipation reduces the propagator of sufficiently smooth Wigner functions to its classical counterpart, the Frobenius-Perron operator, ... More
Entanglement from thermal black body radiationMay 11 2005Sep 06 2005Two non--interacting quantum systems which couple to a common environment with many degrees of freedom initially in thermal equilibrium can become entangled due to the indirect interaction mediated through this heat bath. I examine here the dynamics of ... More
Effect of crystalline disorder on magnetic switching in small magnetic cellsJul 23 2003I present a study of the influence of disorder in thin magnetic films on the switching behavior of small magnetic cells of well defined shape and size. The disorder considered arises from randomly oriented crystalline grains of different shape, size, ... More
T-universal Functions With Prescribed Approximation CurvesNov 13 2003Let be F a family of curves in the unit disc. We show that the set of all functions f holomorphic on the unit disc, which satisfy the following condition, is G-delta and dense in the space of all functions holomorphic on the unit disc: For each compact ... More
The Structure of Divisible Abelian GroupsOct 28 2010Jun 04 2015This is an expository work presenting in detail the proof of the structure theorem for divisible abelian groups. A divisible abelian group is an abelian group that satisfies nD=D for all natural n. The theorem states that any divisible group is a direct ... More
Shortcomings in the Understanding of Why Cosmological Perturbations Look ClassicalJun 01 2009Feb 01 2011There is a persistent state of confusion regarding the account of the quantum origin of the seeds of cosmological structure during inflation. In fact, a recent article (C. Kiefer & D. Polarski, ArXiv: 0810.0087 [astro-ph]) addresses the question "Why ... More
Elementary Proofs Of The Gauss-Bonnet Theorem And Other Integral Formulas In $\Bbb R^3$Sep 16 2015For a compact differentiable surface with boundary embedded in $\Bbb R^3$, we give simple proofs of the Gauss-Bonnet theorem, Poincar\'{e}-Hopf theorem, and several other integral formulas. We complete all of the proofs without using fundamental or differential ... More
Maximum Galactic Disks vs. Hot Dark HalosSep 04 2000A series of arguments is presented for heavy galaxy disks not only in the optical regions, but also in the dark matter dominated regions of spirals. We are testing this possibility with extreme maximum disk N-body models without any conventional spheroidal ... More
On Memory Footprints of Partitioned Sparse MatricesSep 15 2016Processing of sparse matrices in blocks often yields higher efficiency of matrix operations performed within computer programs. On the other hand, partitioning of matrices into blocks represents itself an additional runtime overhead. The presented study ... More
Spectral and scattering theory for Gauss-Bonnet operators on perturbed topological crystalsSep 08 2016In this paper we investigate the spectral and the scattering theory of Gauss--Bonnet operators acting on perturbed periodic combinatorial graphs. Two types of perturbation are considered: either a multiplication operator by a short-range or a long-range ... More
Cross-validation based Nonlinear ShrinkageNov 02 2016Many machine learning algorithms require precise estimates of covariance matrices. The sample covariance matrix performs poorly in high-dimensional settings, which has stimulated the development of alternative methods, the majority based on factor models ... More