Searching Arxiv, refresh for possibly better results.

Results for "W. R. Acevedo"

total 168809took 0.15s
Hamiltonian and action formalisms for two-dimensional gyroviscous MHDMay 09 2014A general procedure for constructing action principles for continuum models via a generalization of Hamilton's principle of mechanics is described. Through the procedure, an action principle for a gyroviscous magnetohydrodynamics (MHD) model is constructed. ... More
Quasinormal frequencies of asymptotically anti-de Sitter black holes in two dimensionsJan 17 2012We calculate exactly the quasinormal frequencies of Klein-Gordon and Dirac test fields propagating in two-dimensional uncharged Achucarro-Ortiz black hole. For both test fields we study whether the quasinormal frequencies are well defined in the massless ... More
Giant Memcapacitance in Topotactic Redox InterfacesMay 14 2019The possibility to develop neuromorphic computing devices able to mimic the extraordinary data processing capabilities of biological systems spurs the research on memristive systems. Memristors with additional functionalities such as robust memcapacitance ... More
Reconstructing the Population Genetic History of the CaribbeanJun 03 2013The Caribbean basin is home to some of the most complex interactions in recent history among previously diverged human populations. Here, by making use of genome-wide SNP array data, we characterize ancestral components of Caribbean populations on a sub-continental ... More
On the Weyl anomaly of 4D Conformal Higher Spins: a holographic approachOct 10 2017Oct 25 2017We present a first attempt to derive the full (type-A and type-B) Weyl anomaly of four dimensional conformal higher spin (CHS) fields in a holographic way. We obtain the type-A and type-B Weyl anomaly coefficients for the whole family of 4D CHS fields ... More
Origin of multistate resistive switching in Ti/manganite/Si$O_x$/Si heterostructuresNov 04 2016Jan 19 2017We report on the growth and characterization of Ti/$La_{1/3}$$Ca_{2/3}$Mn$O_3$/Si$O_x$/n-Si memristive devices. We demonstrate that using current as electrical stimulus unveils an intermediate resistance state, in addition to the usual high and low resistance ... More
Origin of multistate resistive switching in Ti/manganite/Si$O_x$/Si heterostructuresNov 04 2016We report on the growth and characterization of Ti/$La_{1/3}$$Ca_{2/3}$Mn$O_3$/Si$O_x$/n-Si memristive devices. We demonstrate that using current as electrical stimulus unveils an intermediate resistance state, in addition to the usual high and low resistance ... More
Manganite-based three level memristive devices with self-healing capabilityJun 17 2016We report on non-volatile memory devices based on multifunctional manganites. The electric field induced resistive switching of Ti/$La_{1/3}$$Ca_{2/3}$Mn$O_3$/n-Si devices is explored using different measurement protocols. We show that using current as ... More
On the Penetration of Meridional Circulation below the Solar Convection Zone II: Models with Convection Zone, the Taylor-Proudman constraint and Applications to Other StarsJun 09 2009The solar convection zone exhibits a strong level of differential rotation, whereby the rotation period of the polar regions is about 25-30% longer than the equatorial regions. The Coriolis force associated with these zonal flows perpetually "pumps" the ... More
Quantum walks on Cayley graphsMar 08 2005Nov 26 2005We address the problem of the construction of quantum walks on Cayley graphs. Our main motivation is the relationship between quantum algorithms and quantum walks. In particular, we discuss the choice of the dimension of the local Hilbert space and consider ... More
Cross-Domain Entity Resolution in Social MediaAug 03 2016The challenge of associating entities across multiple domains is a key problem in social media understanding. Successful cross-domain entity resolution provides integration of information from multiple sites to create a complete picture of user and community ... More
Directed Transport in classical and quantum chaotic billiardsAug 08 2008Nov 03 2008We construct an autonomous chaotic Hamiltonian ratchet as a channel billiard subdivided by equidistant walls attached perpendicularly to one side of the channel, leaving an opening on the opposite side. A static homogeneous magnetic field penetrating ... More
Hydrodynamics calculations of clusters of drops using the finite volume methodJul 07 2017In this paper is described a numerical scheme that is used to simulate the coalescence process between clusters of water drops immersed in a continuous hydrocarbon phase (n-heptane). Two different values for the initial velocity of the drops were chosen. ... More
Hydrodynamics interactions of clusters of drops: a study of the coalescence phenomena with the finite volume methodJul 07 2017In this work has been proposed a numerical scheme with the aim of simulate the coalescence process between water drops immersed in a continuous phase (n-heptane). This numerical scheme is based in the Finite Volume method and two different values for ... More
Test Sets for Nonnegativity of Polynomials Invariant under a Finite Reflection GroupFeb 01 2015A set $S\subset \mathbb{R}^n$ is a nonnegativity witness for a set $U$ of real homogeneous polynomials if $F$ in $U$ is nonnegative on $\mathbb{R}^n$ if and only if it is nonnegative at all points of $S$. We prove that the union of the hyperplanes perpendicular ... More
Structural stability and characterization of Anosov familiesSep 02 2017Mar 27 2018Anosov families are non-stationary dynamical systems with hyperbolic behavior. Non-trivial examples of Anosov families will be given in this paper. Non-stationary dynamical systems are classified by uniform topological conjugacy. We show the existence ... More
Local Stable and Unstable Manifolds for Anosov FamiliesSep 02 2017Sep 20 2017Anosov families were introduced by A. Fisher and P. Arnoux motivated by generalizing the notion of Anosov diffeomorphism defined on a compact Riemannian manifold. In addition to presenting several properties and examples of Anosov families, in this paper ... More
Self-consistent assessment of Englert-Schwinger model on atomic propertiesNov 15 2017Our manuscript investigates a self-consistent solution of the statistical atom model proposed by Berthold-Georg Englert and Julian Schwinger (the ES model) and benchmarks it against atomic Kohn-Sham and two orbital-free models of the Thomas-Fermi-Dirac ... More
On to the continuity of the map square root of nonnegative isomorphisms in Hilbert spacesApr 10 2015Let H be a real (or complex) Hilbert space. Every nonnegative operator $L \in L(H)$ admits a unique nonnegative square root $R \in L(H)$, i.e., a nonnegative operator $R \in L(H)$ such that $R^{2}= L$. Let $GL^{+}_{S}(H)$ be the set of nonnegative isomorphisms ... More
Optimal execution and price manipulations in time-varying limit order booksApr 12 2012This paper focuses on an extension of the Limit Order Book (LOB) model with general shape introduced by Alfonsi, Fruth and Schied. Here, the additional feature allows a time-varying LOB depth. We solve the optimal execution problem in this framework for ... More
Openness for Anosov familiesSep 02 2017Nov 21 2017Anosov families were introduced by A. Fisher and P. Arnoux motivated by generalizing the notion of Anosov diffeomorphism defined on a compact Riemannian manifold. Roughly, an Anosov family is a two-sided sequence of diffeomorphisms (or non-stationary ... More
Supernovae Sparked By Dark Matter in White DwarfsApr 26 2019It was recently demonstrated that asymmetric dark matter can ignite supernovae by collecting and collapsing inside lone sub-Chandrasekhar mass white dwarfs, and that this may be the cause of Type Ia supernovae. A ball of asymmetric dark matter accumulated ... More
Structural stability and a characterization of Anosov familiesSep 02 2017Mar 01 2019Anosov families are non-stationary dynamical systems with hyperbolic behavior. Non-trivial examples of Anosov families will be given in this paper. We show the existence of invariant manifolds, the structrural stability and a characterization for a certain ... More
On the Continuity of the Topological Entropy of Non-autonomous Dynamical SystemsSep 03 2017Let $M$ be a compact Riemannian manifold. The set $\text{F}^{r}(M)$ consisting of sequences $(f_{i})_{i\in\mathbb{Z}}$ of $C^{r}$-diffeomorphisms on $M$ can be endowed with the compact topology or with the strong topology. A notion of topological entropy ... More
Sharp isoperimetric inequalities for small volumes in complete noncompact Riemannian manifolds of bounded geometry involving the scalar curvatureNov 05 2016We provide an isoperimetric comparison theorem for small volumes in an $n$-dimensional Riemannian manifold $(M^n,g)$ with strong bounded geometry, as in Definition $2.3$, involving the scalar curvature function. Namely in strong bounded geometry, if the ... More
A non linear approximation method for solving high dimensional partial differential equations: Application in FinanceSep 15 2013Sep 17 2013We study an algorithm which has been proposed by Chinesta et al. to solve high-dimensional partial differential equations. The idea is to represent the solution as a sum of tensor products and to compute iteratively the terms of this sum. This algorithm ... More
A multi-scale code for flexible hybrid simulationsNov 09 2012Multi-scale computer simulations combine the computationally efficient classical algorithms with more expensive but also more accurate ab-initio quantum mechanical algorithms. This work describes one implementation of multi-scale computations using the ... More
Second-order accurate ensemble transform particle filtersAug 29 2016Sep 22 2016Particle filters (also called sequential Monte Carlo methods) are widely used for state and parameter estimation problems in the context of nonlinear evolution equations. The recently proposed ensemble transform particle filter (ETPF) (S. Reich, {\it ... More
Quasinormal frequencies of asymptotically flat two-dimensional black holesMay 13 2011We discuss whether the minimally coupled massless Klein-Gordon and Dirac fields have well defined quasinormal modes in single horizon, asymptotically flat two-dimensional black holes. To get the result we solve the equations of motion in the massless ... More
A theoretical study of the interaction between DNA/RNA and the noble metal atoms of gold and silver - Ground-state propertiesMar 14 2014May 20 2014Here, we present results from a study of DNA/RNA bases interacting with gold and silver atoms at three charge states: neutral, cationic, and anionic. Using a real-space DFT methodology, we describe the nature of the stability, bonding, and electronic ... More
Second-order accurate ensemble transform particle filtersAug 29 2016Apr 10 2017Particle filters (also called sequential Monte Carlo methods) are widely used for state and parameter estimation problems in the context of nonlinear evolution equations. The recently proposed ensemble transform particle filter (ETPF) (S.~Reich, {\it ... More
Sharp isoperimetric inequalities for small volumes in complete noncompact Riemannian manifolds of bounded geometry involving the scalar curvatureNov 05 2016Nov 11 2016We provide an isoperimetric comparison theorem for small volumes in an $n$-dimensional Riemannian manifold $(M^n,g)$ with strong bounded geometry, as in Definition $2.3$, involving the scalar curvature function. Namely in strong bounded geometry, if the ... More
Double-Recurrence Fibonacci Numbers and GeneralizationsMar 18 2019Let $(F_n)_{n\geq 0}$ be the Fibonacci sequence given by the recurrence $F_{n+2}=F_{n+1}+F_n$, for $n\geq 0$, where $F_0=0$ and $F_1=1$. There are several generalizations of this sequence and also several interesting identities. In this paper, we investigate ... More
On simple Lie 2-algebra of toral rank 3Feb 28 2019Simple Lie algebras of finite dimension over an algebraically closed field of characteristic 0 or $p> 3$ were recently classified. However, the problem over an algebraically closed field of characteristics 2 or 3 there exist only partial results. The ... More
Challenges of Achieving Efficient Simulations Through Model AbstractionJul 20 2018Coupled natural systems are generally modeled at multiple abstraction levels. Both structural scale and behavioral complexity of these models are determinants in the kinds of questions that can be posed and answered. As scale and complexity of models ... More
Mean dimension and metric mean dimension for non-autonomous dynamical systemsMay 14 2019In this paper we extend the definitions of mean dimension and metric mean di-mension for non-autonomous dynamical systems. We show some properties of this extension and furthermore some applications to the mean dimension and metric mean dimension of single ... More
Electronic structure of Gold, Aluminum and Gallium Superatom ComplexesApr 26 2011May 25 2011Using ab-initio computational techniques on crystal determined clusters, we report on the similarities and differences of Al$_{50}$(C$_5$(CH$_3)_5)_{12}$, Ga$_{23}$(N(Si(CH$_3)_{3}$)$_{2}$)$_{11}$, and Au$_{102}$(SC$_7$O$_2$H$_5$)$_{44}$ ligand-protected ... More
Exploring scalar quantum walks on Cayley graphsSep 29 2006Sep 30 2006A quantum walk, \emph{i.e.}, the quantum evolution of a particle on a graph, is termed \emph{scalar} if the internal space of the moving particle (often called the coin) has a dimension one. Here, we study the existence of scalar quantum walks on Cayley ... More
Dynamics of the solar tachocline III: Numerical solutions of the Gough and McIntyre modelApr 11 2013We present the first numerical simulations of the solar interior to exhibit a tachocline consistent with the Gough and McIntyre (1998) model. We find nonlinear, axisymmetric, steady-state numerical solutions in which: (1) a large-scale primordial field ... More
Constructing cocyclic Hadamard matrices of order 4pApr 25 2019Cocyclic Hadamard matrices (CHMs) were introduced by de Launey and Horadam as a class of Hadamard matrices with interesting algebraic properties. \'O Cath\'ain and R\"oder described a classification algorithm for CHMs of order $4n$ based on relative difference ... More
Stokes and Navier-Stokes equations with Navier boundary conditionMay 20 2018Sep 22 2018We study the stationary Stokes and Navier-Stokes equations with non-homogeneous Navier boundary condition in a bounded domain $\Omega\subset\mathbb{R}^{3}$ of class $\mathcal{C}^{1,1}$. We prove existence, uniqueness of weak and strong solutions in $\mathbf{W}^{1,p}(\Omega)$ ... More
Fluid Limits of Pure Jump Markov Processes: a Practical GuideOct 08 2002Dec 23 2002A rescaled Markov chain converges uniformly in probability to the solution of an ordinary differential equation, under carefully specified assumptions. The presentation is much simpler than those in the outside literature. The result may be used to build ... More
The Four Point Permutation Test for Latent Block Structure in Incidence MatricesOct 04 2018Transactional data may be represented as a bipartite graph $G:=(L \cup R, E)$, where $L$ denotes agents, $R$ denotes objects visible to many agents, and an edge in $E$ denotes an interaction between an agent and an object. Unsupervised learning seeks ... More
The Repeated Solicitation ModelAug 11 1998Sep 15 1998This paper presents a probabilistic analysis of what we call the "repeated solicitation model". To give a specific context, suppose B is a direct marketing company with a list of S sales prospects. At epoch 1, B sends a solicitation to every prospect ... More
Geometrically Intrinsic Nonlinear Recursive Filters II: FoundationsSep 06 1998This paper contains the technical foundations from stochastic differential geometry for the construction of geometrically intrinsic nonlinear recursive filters. A diffusion X on a manifold N is run for a time interval T, with a random initial condition. ... More
Geometrically Intrinsic Nonlinear Recursive Filters I: AlgorithmsSep 06 1998The Geometrically Intrinsic Nonlinear Recursive Filter, or GI Filter, is designed to estimate an arbitrary continuous-time Markov diffusion process X subject to nonlinear discrete-time observations. The GI Filter is fundamentally different from the much-used ... More
Functional advantages offered by many-body coherences in biochemical systemsAug 10 2017Quantum coherence phenomena driven by electronic-vibrational (vibronic) interactions, are being reported in many pulse (e.g. laser) driven chemical and biophysical systems. But what systems-level advantage(s) do such many-body coherences offer to future ... More
Pulsed Generation of Quantum Coherences and Non-classicality in Light-Matter SystemsJun 23 2017Aug 17 2018We show that a pulsed stimulus can be used to generate many-body quantum coherences in light-matter systems of general size. Specifically, we calculate the exact real-time evolution of a driven, generic out-of-equilibrium system comprising an arbitrary ... More
Intrinsic Location Parameter of a Diffusion ProcessSep 06 1998For nonlinear functions f of a random vector Y, E[f(Y)] and f(E[Y]) usually differ. Consequently the mathematical expectation of Y is not intrinsic: when we change coordinate systems, it is not invariant.This article is about a fundamental and hitherto ... More
Optical Light Curve of the Type Ia Supernova 1998bu in M96 and the Supernova Calibration of the Hubble ConstantNov 12 1998We present the UBVRI light curves of the Type Ia supernova SN 1998bu which appeared in the nearby galaxy M96 (NGC 3368). M96 is a spiral galaxy in the Leo I group which has a Cepheid-based distance. Our photometry allows us to calculate the absolute magnitude ... More
Robust quantum correlations in out-of-equilibrium matter-light systemsApr 16 2015Sep 15 2015High precision macroscopic quantum control in interacting light-matter systems remains a significant goal toward novel information processing and ultra-precise metrology. We show that the out-of-equilibrium behavior of a paradigmatic light-matter system ... More
Large dynamic light-matter entanglement from driving neither too fast nor too slowMar 18 2015Oct 01 2015A significant problem facing next-generation quantum technologies is how to generate and manipulate macroscopic entanglement in light and matter systems. Here we report a new regime of dynamical light-matter behavior in which a giant, system-wide entanglement ... More
Damage detection in a unidimensional truss using the firefly optimization algorithm and finite elementsJun 09 2017Apr 24 2018In this paper, we investigate the damage detection of structures seen as an optimization problem, using modal characterization to evaluate the dynamic response of the structure given a damage model. We implemented the firefly optimization algorithm with ... More
On Axiomatization of Inconsistency Indicators for Pairwise ComparisonsJul 24 2013Oct 13 2013We examine the notion of inconsistency in pairwise comparisons and propose an axiomatization which is independent of any method of approximation or the inconsistency indicator definition (e.g., Analytic Hierarchy Process, AHP). It has been proven that ... More
Interface magnetic moments enhancement of FePt-L1$_0$/MgO(001): an ab-initio studyDec 16 2013The interface between FePt--L1$_0$ and MgO(001) alloys has been studied using density functional calculations. Because the stacking of the face-centered tetragonal L1$_0$ phase is formed by alternating Fe and Pt planes, both the Fe- and Pt-terminated ... More
Electronic and magnetic properties of bimetallic L1$_0$ cuboctahedral clusters by means of a fully relativistic density functional based calculationsJul 24 2012By means of density functional theory (DFT) and the generalized gradient approximation (GGA) we present a structural, electronic and magnetic study of FePt, CoPt, FeAu and FePd based L1$_0$ ordered cuboctahedral nanoparticles, with total numbers of atoms, ... More
New dynamical scaling universality for quantum networks across adiabatic quantum phase transitionsDec 18 2013We reveal universal dynamical scaling behavior across adiabatic quantum phase transitions (QPTs) in networks ranging from traditional spatial systems (Ising model) to fully connected ones (Dicke and Lipkin-Meshkov-Glick models). Our findings, which lie ... More
Oxygen vacancies dynamics in redox-based interfaces: Tailoring the memristive responseNov 23 2018Redox-based memristive devices are among the alternatives for the next generation of non volatile memories, but also candidates to emulate the behavior of synapses in neuromorphic computing devices. It is nowadays well established that the motion of oxygen ... More
A full electromagnetic Particle-In-Cell code to model collisionless plasmas in magnetic trapsDec 08 2018A lot of plasma physics problems are not amenable to exact solutions due to many reasons. It is worth mentioning among them, for example, nonlinearity of the motion equations, variable coefficients or non lineal conditions on known or unknown borders. ... More
Exact Finite-Size Scaling and Corrections to Scaling in the Ising Model with Brascamp-Kunz Boundary ConditionsMar 15 2001The Ising model in two dimensions with the special boundary conditions of Brascamp and Kunz is analysed. Leading and sub-dominant scaling behaviour of the Fisher zeroes are determined exactly. The finite-size scaling, with corrections, of the specific ... More
Radio astrometry with chromatic AGN core positionsSep 04 2009Aims: The effect of frequency-dependent AGN core positions (``core-shifts'') on radio Very Long Baseline Interferometry (VLBI) global astrometry measurements is investigated. Methods: The basic equations relating to VLBI astrometry are reviewed, including ... More
Prediction of a surface state and a related surface insulator-metal transition for the (100) surface of stochiometric EuOMar 12 2001We calculate the temperature and layer-dependent electronic structure of a 20-layer EuO(100)-film using a combination of first-principles and model calculation based on the ferromagnetic Kondo-lattice model. The results suggest the existence of a EuO(100) ... More
Thickness dependent Curie temperatures of ferromagnetic Heisenberg filmsJan 06 1999We develop a procedure for calculating the magnetic properties of a ferromagnetic Heisenberg film with single-ion anisotropy which is valid for arbitrary spin and film thickness. Applied to sc(100) and fcc(100) films with spin S=7/2 the theory yields ... More
Theory of Magnetocrystalline Anisotropy Energy for Wires and Corrals of Fe adatoms: A Non-Perturbative TheoryMay 22 1996The magnetocrystalline anisotropy energy $E_{anis}$ for free-standing chains (quantum wires) and rings (quantum corrals) of Fe-adatoms $N=$(2...48) is determined using an electronic tight-binding theory. Treating spin-orbit coupling non-perturbatively, ... More
First Measurement of the Neutron $β$-Asymmetry with Ultracold NeutronsSep 17 2008We report the first measurement of angular correlation parameters in neutron $\beta$-decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for $\sim 30$ s in a Cu decay volume. The $\vec{\mu}_n ... More
Stability of the MIDI photometry: the case of CircinusDec 10 2013In principle, the MID-infrared Interferometric instrument (MIDI) at the Very Large Telescope Array (VLTI) should always measure the same calibrated total flux spectrum for a specific source, independent of the instrument settings and the baseline geometry. ... More
Low-Energy Thermal Photons from Meson-Meson BremsstrahlungApr 13 2006Sep 04 2007Within an effective hadronic model including electromagnetic interactions via a U$_{\rm em}$(1) gauge, we reinvestigate photon Bremsstrahlung from a hot hadronic gas as expected to be formed in relativistic heavy-ion collisions at SPS energies. We calculate ... More
Equiangular line systems and switching classes containing regular graphsDec 12 2016Sep 09 2017We develop the theory of equiangular lines in Euclidean spaces. Our focus is on the question of when a Seidel matrix having precisely three distinct eigenvalues has a regular graph in its switching class. We make some progress towards an answer to this ... More
Introduction to Vertex Algebras, Borcherds Algebras, and the Monster Lie AlgebraAug 31 1993Sep 03 1993The theory of vertex algebras constitutes a mathematically rigorous axiomatic formulation of the algebraic origins of conformal field theory. In this context Borcherds algebras arise as certain ``physical'' subspaces of vertex algebras. The aim of this ... More
Extended Particles and the Exterior CalculusOct 27 2016These notes were delivered as a series of NIMROD lectures at the Rutherford Appleton Laboratory by the author in February 1976 (RL-76-022). The purpose of these lectures was primarily two-fold: to discuss the classical theory of free point particles, ... More
Decomposition of the forces on a body moving in an incompressible fluidMay 07 2019The identification of separate physical features contributing to the force resultants on a moving body is useful for insight into the associated flow, and for conceptual modelling. A natural approach is to seek a component due to viscosity and an `inviscid' ... More
The quantum AdS_5 x S^5 superstring at finite couplingAug 22 2013The integrability of string theory in AdS_5 x S^5 and of the dilatation operator of N=4 super-Yang-Mills theory has been used to propose an exact solution to the spectral problem in these theories. Weak coupling perturbation theory both in gauge theory ... More
Electromagnetic and Mass Difference Corrections in pion N ScatteringDec 31 2004Coulomb and mass difference corrections to low-energy pion-nucleon scattering are calculated and compared with previous work including potential models, dispersion relation methods and chiral perturbation theory calculations. Particular attention is paid ... More
The Separation of Secondary Positrons Produced in the Galaxy from the High Energy Positrons that are Observed Recent Space Experiments on PAMELA and AMS2Dec 22 2015The large intensity of greater than 10 GeV positrons which apparently come from sources outside the Earth-Sun system observed recently by many spacecraft (PAMELA, FERMI, AMS2) is still a mystery with broad implications. In our attempts to solve this mystery ... More
On Quantization, the Generalized Schrödinger Equation and Classical MechanicsDec 30 2012Using a new state-dependent, $\lambda$-deformable, linear functional operator, ${\cal Q}_{\psi}^{\lambda}$, which presents a natural $C^{\infty}$ deformation of quantization, we obtain a uniquely selected non--linear, integro--differential Generalized ... More
Notes on stable maps and quantum cohomologyAug 15 1996May 17 1997These are notes from a jointly taught class at the University of Chicago and lectures by the first author in Santa Cruz. Topics covered include: construction of moduli spaces of stable maps, Gromov-Witten invariants, quantum cohomology, and examples. ... More
Comment on "Frustrating interactions and broadened magnetic interactions in the edge-sharing CuO_2 chains in La_5 Ca_9 Cu_24 O_41"Sep 28 2003Dec 14 2003Using Monte Carlo techniques, we show that the two--dimensional anisotropic Heisenberg model reproducing nicely inelastic neutron scattering measurements on La_5 Ca_9 Cu_24 O_41 (Matsuda et al. [Phys. Rev. B 68, 060406(R) (2003)]) seems to be insufficient ... More
Conformal Coupling of Higher Spin Gauge Fields to a Scalar Field in $AdS_{4}$ and Generalized Weyl InvarianceMar 24 2004The higher spin interaction currents for the conformally coupled scalar in $AdS_{4}$ space for both regular and irregular boundary condition corresponding to the free and interacting critical point of the boundary O(N) sigma model are constructed. The ... More
Simplicial moves on complexes and manifoldsNov 20 1999Here are versions of the proofs of two classic theorems of combinatorial topology. The first is the result that piecewise linearly homeomorphic simplicial complexes are related by stellar moves. This is used in the proof, modelled on that of Pachner, ... More
Necessary Conditions for Schur-PositivityJun 12 2007Dec 21 2007In recent years, there has been considerable interest in showing that certain conditions on skew shapes A and B are sufficient for the difference s_A - s_B of their skew Schur functions to be Schur-positive. We determine necessary conditions for the difference ... More
Comparing skew Schur functions: a quasisymmetric perspectiveJul 23 2013Jan 16 2014Reiner, Shaw and van Willigenburg showed that if two skew Schur functions s_A and s_B are equal, then the skew shapes A and B must have the same "row overlap partitions." Here we show that these row overlap equalities are also implied by a much weaker ... More
Cavlectometry: Towards Holistic Reconstruction of Large Mirror ObjectsSep 14 2014We introduce a method based on the deflectometry principle for the reconstruction of specular objects exhibiting significant size and geometric complexity. A key feature of our approach is the deployment of an Automatic Virtual Environment (CAVE) as pattern ... More
Quantum Hysteresis in Coupled Light-Matter SystemsJun 28 2016Sep 08 2016We investigate the non-equilibrium quantum dynamics of a canonical light-matter system, namely the Dicke model, when the light-matter interaction is ramped up and down through a cycle across the quantum phase transition. Our calculations reveal a rich ... More
Structure of large random hypergraphsSep 04 2001Jan 16 2004The theme of this paper is the derivation of analytic formulae for certain large combinatorial structures. The formulae are obtained via fluid limits of pure jump type Markov processes, established under simple conditions on the Laplace transforms of ... More
Differential equation approximations for Markov chainsOct 17 2007Apr 23 2008We formulate some simple conditions under which a Markov chain may be approximated by the solution to a differential equation, with quantifiable error probabilities. The role of a choice of coordinate functions for the Markov chain is emphasised. The ... More
Transverse hydrodynamics with sudden hadronization -- production of strangenessDec 17 2009We consider a physical scenario for ultra-relativistic heavy-ion collisions where, at the early stage, only transverse degrees of freedom of partons are thermalized, while the longitudinal motion is described by free streaming. When the energy density ... More
Space-time foam in 2D and the sum over topologiesAug 31 2003It is well-known that the sum over topologies in quantum gravity is ill-defined, due to a super-exponential growth of the number of geometries as a function of the space-time volume, leading to a badly divergent gravitational path integral. Not even in ... More
A Galactic Cosmic Ray Electron Spectrum from 2 MeV to 2 TeV That Fits Voyager 5-60 MeV Data at Low Energies and PAMELA and AMS-2 Data at 10 GeV Using an Electron Source Spectrum E^-2.25 A Calculation Using a Monte Carlo Diffusion ModelAug 25 2015In this paper we fit the observed galactic cosmic ray electron spectrum from a few MeV to 1 TeV. New data from Voyager from 5-60 MeV beyond the heliopause is used along with high energy data from the PAMELA, FERMI and AMS-2 instruments in Earth orbit. ... More
Circumbinary disk evolutionApr 10 2002We study the evolution of circumbinary disks surrounding classical T Tau stars. High resolution numerical simulations are employed to model a system consisting of a central eccentric binary star within an accretion disk. The disk is assumed to be infinitesimally ... More
Temperature-dependent bandstructure of bulk EuOMar 12 2001We present calculations for the temperature-dependent electronic structure of bulk ferromagnetic EuO based on a parametrization of the d-f model Hamiltonian using results of first-principles TB-LMTO band structure calculations. The presented method avoids ... More
Hadron Resonances Within a Constituent-Quark ModelSep 01 2011In order to get a more realistic description of the hadron spectrum we extend a constituent-quark model by explicit mesonic degrees of freedom. The resulting system of constituent (anti)quarks, which are subject to an instantaneous confining force, and ... More
Rotational Evolution of Solar-Like Stars in Clusters from Pre-Main Sequence to Main Sequence: Empirical ResultsJul 30 2005Rotation periods are now available for ~500 pre-main sequence and recently arrived main sequence stars of solar-like mass (0.4-1.2 M_sun) in five nearby young clusters: the Orion Nebula Cluster, NGC 2264, alpha Per, IC 2602 and the Pleiades. In combination ... More
New Class of Solvable and Integrable Many-Body ModelsMar 25 2002Mar 26 2002Integrability conditions for systems of bosons or fermions with seniority conserving hamiltonians are derived. The conditions are shown to be invariant under a large class of transformations of the interaction matrix elements. Previously published integrable ... More
Joint Time--Frequency Analysis: a tool for exploratory analysis and filtering of non-stationary time seriesApr 10 2002It is the purpose of the paper to describe the virtues of time-frequency methods for signal processing applications, having astronomical time series in mind. Different methods are considered and their potential usefulness respectively drawbacks are discussed ... More
On an interpolative Schrödinger equation and an alternative classical limitDec 15 2013We introduce a simple deformed quantization prescription that interpolates the classical and quantum sectors of Weinberg's nonlinear quantum theory. The result is a novel classical limit where $\hbar$ is kept fixed while a dimensionless mesoscopic parameter, ... More
Newtonian Quantum GravityJul 04 1995Puts forward a complete scenario for interpreting nonlinear field theories highlighting the role played by gravitational self--energy in enabling a consistent revival of the Schroedinger approach to unifying micro and macro physics.
Charm-System Tests of CPT with FOCUSDec 28 2001We discuss a search for CPT violation in neutral charm meson oscillations. The data come from the Fermilab fixed-target experiment FOCUS. While flavor mixing in the charm sector is predicted to be small by the standard model, it is still possible to investigate ... More
Vacuum Polarization in QED with World-Line MethodsJan 26 2000Motivated by several recent papers on string-inspired calculations in QED, we here present our own use of world-line techniques in order to calculate the vacuum polarization and effective action in scalar and spinor QED with external arbitrary constant ... More
Comments on the nuclear symmetry energyNov 14 2002According to standard textbooks, the nuclear symmetry energy originates from the {\it kinetic} energy and the {\it interaction} itself. We argue that this view requires certain modifications. We ascribe the physical origin of the {\it kinetic} term to ... More
Rotations in isospace: a doorway to the understanding of neutron-proton superfluidity in N=Z nucleiOct 13 2000Oct 17 2000The $T$=2 excitations in even-even $N$=$Z$ nuclei are calculated within the isospin cranked mean-field approach. The response of pairing correlations to rotation in isospace is investigated. It is shown that whereas the isovector pairing rather modestly ... More