Results for "Aram Karakhanyan"

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Log-gas equilibria with free boundary and optimal transportApr 12 2019Apr 17 2019We study the probability measures $\rho\in \mathcal M(\mathbb R^2)$ minimizing the functional \[ J[\rho]=\iint \log\frac1{|x-y|}d\rho(x)d\rho(y)+d^2(\rho, \rho_0), \] where $\rho_0$ is a given probability measure and $d(\rho, \rho_0)$ is the 2-Wasserstein ... More
$K$-surfaces with free boundariesMay 13 2017Jun 10 2017A well-known question in classical differential geometry and geometric analysis asks for a description of possible boundaries of $K$-surfaces, which are smooth, compact hypersurfaces in $\mathbb{R}^d$ having constant Gauss curvature equal to $K \geq 0$. ... More
Regularity for a quasilinear continuous casting problemDec 27 2015In this paper study the regularity of continuous casting problem \begin{equation} \hbox{div}(|\nabla u|^{p-2}\nabla u-{\bf v} \beta(u))=0\tag{$\sharp$} \end{equation} for prescribed constant velocity $\bf v$ and enthalpy $\beta(u)$ with jump discontinuity ... More
An inverse problem for the refractive surfaces with parallel lightingMar 11 2014Dec 27 2015In this article we examine the regularity of two types of weak solutions to a Monge-Amp\`ere type equation which emerges in a problem of finding surfaces that refract coaxial light rays emitted from source domain and striking a given target after refraction. ... More
Log-gas equilibria with free boundary and optimal transportApr 12 2019We study the probability measures $\rho\in \mathcal M(\mathbb R^2)$ minimizing the functional \[ J[\rho]=\iint \log\frac1{|x-y|}d\rho(x)d\rho(y)+d^2(\rho, \rho_0), \] where $\rho_0$ is a given probability measure and $d(\rho, \rho_0)$ is the 2-Wasserstein ... More
Blaschke's rolling ball theorem and the Trudinger-Wang monotone bendingDec 27 2015We revisit the classical rolling ball theorem of Blaschke for convex surfaces with positive curvature and show that it is linked to another inclusion principle in the optimal mass transportation theory due to Trudinger and Wang. We also discuss an application ... More
A new discrete monotonicity formula with application to a two-phase free boundary problem in dimension twoSep 01 2015We continue the analysis of the two-phase free boundary problems initiated in \cite{DK}, where we studied the linear growth of minimizers in a Bernoulli type free boundary problem at the non-flat points and the related regularity of free boundary. There, ... More
On a conjecture of De Giorgi related to homogenizationSep 20 2014Dec 29 2015For a periodic vector field $\bf F$, let ${\bf X}^\epsilon$ solve the dynamical system \begin{equation*} \frac{d{\bf X}^\epsilon}{dt} = {\bf F}\left(\frac {{\bf X}^\epsilon}\epsilon\right) . \end{equation*} In \cite{DeGiorgi} Ennio De Giorgi enquiers ... More
On a conjecture of De Giorgi related to homogenizationSep 20 2014Apr 25 2017For a periodic vector field $\bf F$, let ${\bf X}^\epsilon$ solve the dynamical system \begin{equation*} \frac{d{\bf X}^\epsilon}{dt} = {\bf F}\left(\frac {{\bf X}^\epsilon}\epsilon\right) . \end{equation*} In \cite{DeGiorgi} Ennio De Giorgi enquiers ... More
Analysis of a free boundary at contact points with Lipschitz dataMay 22 2012Sep 23 2013In this paper we consider a minimization problem for the functional $$ J(u)=\int_{B_1^+}|\nabla u|\sp 2+\lambda_{+}^2\chi_{\{u>0\}}+\lambda_{-}^2\chi_{\{u\leq0\}}, $$ in the upper half ball $B_1^+\subset\R^n, n\geq 2$ subject to a Lipschitz continuous ... More
Potential theoretic approach to Schauder estimates for the fractional LaplacianFeb 17 2016Jun 30 2016We present an elementary approach for the proof of Schauder estimates for the equation $(-\Delta)^s u(x)=f(x), \,0<s<1$, with $f$ having a modulus of continuity $\omega_f$, based on the Poisson representation formula and dyadic ball approximation argument. ... More
Estimates for capacity and discrepancy of convex surfaces in sieve-like domains with an application to homogenizationMay 08 2015We consider the intersection of a convex surface $\Ga$ with a periodic perforation of $\R^d$, which looks like a sieve, given by $T_\e = \bigcup_{k\in \Z^d}\{\e k+a_\e T\}$ where $T$ is a given compact set and $a_\e\ll \e$ is the size of the perforation ... More
On derivation of Euler-Lagrange Equations for incompressible energy-minimizersJul 24 2008We prove that any distribution $q$ satisfying the equation $\nabla q=\div{\bf f}$ for some tensor ${\bf f}=(f^i_j), f^i_j\in h^r(U)$ ($1\leq r<\infty$) -the {\it local Hardy space}, $q$ is in $h^r$, and is locally represented by the sum of singular integrals ... More
Stratification of free boundary points for a two-phase variational problemAug 29 2015Dec 10 2015In this paper we study the two-phase Bernoulli type free boundary problem arising from the minimization of the functional $$ J(u):=\int_{\Omega}|\nabla u|^p +\lambda_+^p\,\chi_{\{u>0\}} +\lambda_-^p\,\chi_{\{u\le 0\}}, \quad 1<p<\infty. $$ Here $\Omega ... More
A nonlinear free boundary problem with a self-driven Bernoulli conditionNov 01 2016We study a Bernoulli type free boundary problem with two phases $$J[u]=\int_{\Omega}|\nabla u(x)|^2\,dx+\Phi\big({\mathcal M}_-(u), {\mathcal{M}}_+(u)\big), \quad u-\bar u\in W^{1,2}_0(\Omega), $$ where $\bar u\in W^{1,2}(\Omega)$ is a given boundary ... More
A class of unstable free boundary problemsDec 09 2015We consider the free boundary problem arising from an energy functional which is the sum of a Dirichlet energy and a nonlinear function of either the classical or the fractional perimeter. The main difference with the existing literature is that the total ... More
Limit behaviour of a singular perturbation problem for the biharmonic operatorFeb 18 2019We study here a singular perturbation problem of biLaplacian type, which can be seen as the biharmonic counterpart of classical combustion models. We provide different results, that include the convergence to a free boundary problem driven by a biharmonic ... More
The non-local action for the induced 2d supergravityJun 19 1997The two-dimensional simple supergravity is reexamined from the point of view of super-Weyl group cohomologies. The non-local form of the effective action of 2d supergravity which generalise the famous $R 1/\Box R$ is obtained.
Zero-curvature condition in Calogero modelSep 19 2013Sep 21 2013We consider the mutual commutativity of Dunkl operators of the rational Calogero model as zero-curvature condition and calculate the non-local operator, related to these flat connections. This operator has physical meaning of particular scattering matrix ... More
New solutions to the $s\ell_q(2)$-invariant Yang-Baxter equations at roots of unity: cyclic representationsMar 29 2012Aug 22 2012We find the all solutions to the $sl_q(2)$-invariant multi-parametric Yang-Baxter equations (YBE) at $q=i$ defined on the cyclic (semi-cyclic, nilpotent) representations of the algebra. We are deriving the solutions in form of the linear combinations ... More
Solutions to the Yang-Baxter equations with $osp_q(1|2)$ symmetry: Lax operatorsJun 17 2008Jun 28 2008We find a new $4\times4$ solution to the $osp_q(1|2)$-invariant Yang-Baxter equation with simple dependence on the spectral parameter and propose $2\times 2$ matrix expressions for the corresponding Lax operator. The general inhomogeneous universal spectral-parameter ... More
Fusion Rules of the Lowest Weight Representations of osp_q(1|2) at Roots of Unity: Polynomial Realization and Degeneration at Roots of UnityFeb 08 2006Aug 27 2009The degeneracy of the lowest weight representations of the quantum superalgebra $osp_q(1|2)$ and their tensor products at exceptional values of %when deformation parameter $q$ takes exceptional values is studied. The main features of the structures of ... More
Conserved currents of the three-reggeon interactionFeb 22 1999We consider an extension of Lipatov's conjecture about the deep relation between amplitudes in the high-energy limit of QCD and XXX Heisenberg chains with non-compact spins.
Jordan-Schwinger Representations and Factorised Yang-Baxter OperatorsOct 27 2009Apr 07 2010The construction elements of the factorised form of the Yang-Baxter R operator acting on generic representations of q-deformed sl(n+1) are studied. We rely on the iterative construction of such representations by the restricted class of Jordan-Schwinger ... More
Polynomial Realization of $s\ell_q(2)$ and Fusion Rules at Exceptional Values of $q$Feb 09 2005Representations of the $s\ell_q(2)$ algebra are constructed in the space of polynomials of real (complex) variable for $q^N=1$. The spin addition rule based on eigenvalues of Casimir operator is illustrated on few simplest cases and conjecture for general ... More
High-energy scattering in gauge theories and integrable spin chainsFeb 03 1999In the leading log approximation and at large $N_C$ the interaction of two fermionic and one gluonic reggeons is described by an integrable system corresponding to an open spin chain.
Beyond Collins and Sivers: further measurements of the target transverse spin-dependent azimuthal asymmetries in semi-inclusive DIS from COMPASSMay 16 2007In semi-inclusive DIS of polarized leptons on a transversely polarized target eight azimuthal modulations appear in the cross-section. Within QCD parton model four azimuthal asymmetries can be interpreted at leading order, two of them being the already ... More
Cahn and Sivers effects in the target fragmentation region of SIDISApr 11 2005LEPTO event generator is modified to describe the azimuthal modulations arising from Cahn and Sivers effects. The comparisons with some existing data in the current fragmentation region of SIDIS are presented. The predictions for Cahn and Sivers asymmetries ... More
Isospin and isospin/strangeness correlations in relativistic heavy ion collisionsDec 11 2007A fundamental symmetry of nuclear and particle physics is isospin whose third component is the Gell-Mann/Nishijima expression I(z)=Q-(B+S)/2 . The role of isospin symmetry in relativistic heavy ion collisions is studied. An isospin I(z), strangeness S ... More
New Quark Distributions and Semi-Inclusive Electroproduction on Polarized NucleonsDec 13 1994Jan 10 1995The quark-parton model calculation including the effects of intrinsic transverse momentum and of all six twist-two distribution functions of quarks in polarized nucleons is performed. It is demonstrated that new twist-two quark distribution functions ... More
Azimuthal Correlations in the Structure Functions of polarized Dihadron Semi-Inclusive Deep Inelastic ScatteringAug 28 2014Mar 24 2015Azimuthal correlations in two hadron production in deep inelastic scattering of unpolarized leptons off transversely polarized nucleon are discussed. Specifically, a simple approach for accessing ratios of structure functions corresponding to Sivers effect ... More
Baxter Q-operators of the XXZ chain and R-matrix factorizationNov 02 2005Nov 14 2005We construct Baxter operators as generalized transfer matrices being traces of products of generic $R$ matrices. The latter are shown to factorize into simpler operators allowing for explicit expressions in terms of functions of a Weyl pair of basic operators. ... More
The structure of invariants in conformal mechanicsFeb 10 2014We investigate the integrals of motion of general conformal mechanical systems with and without confining harmonic potential as well as of the related angular subsystems, by employing the SL(2,R) algebra and its representations. In particular, via the ... More
Heisenberg spin chains based on sl(2|1) symmetryMar 10 2000We find solutions of the Yang-Baxter equation acting on tensor product of arbitrary representations of the superalgebra sl(2|1). Based on these solutions we construct the local Hamiltonians for integrable homogeneous periodic chains and open chains.
Yang-Baxter R operators and parameter permutationsMar 08 2007Jun 01 2007We present an uniform construction of the solution to the Yang- Baxter equation with the symmetry algebra $s\ell(2)$ and its deformations: the q-deformation and the elliptic deformation or Sklyanin algebra. The R-operator acting in the tensor product ... More
Universal R operator with Jordanian deformation of conformal symmetryOct 15 2003Oct 24 2003The Jordanian deformation of $sl(2)$ bi-algebra structure is studied in view of physical applications to breaking of conformal symmetry in the high energy asymptotics of scattering. Representations are formulated in terms of polynomials, generators in ... More
Universal R-matrix as integral operatorFeb 20 2001We derive the integral operator form for the general rational solution of the Yang-Baxter equation with $s\ell(2|1)$ symmetry. Considering the defining relations for the kernel of the R-operator as a system of second order differential equations we observe ... More
Universal R operator with deformed conformal symmetryNov 14 2001May 28 2002We study the general solution of the Yang-Baxter equation with deformed $sl(2)$ symmetry. The universal R operator acting on tensor products of arbitrary representations is obtained in spectral decomposition and in integral forms. The results for eigenvalues, ... More
Orthogonal and symplectic Yangians and Yang-Baxter R-operatorsNov 19 2015Yang-Baxter R operators symmetric with respect to the orthogonal and symplectic algebras are considered in an uniform way. Explicit forms for the spinorial and metaplectic R operators are obtained. L operators, obeying the RLL relation with the orthogonal ... More
Coherent Communication of Classical MessagesJul 12 2003Jan 09 2004We define "coherent communication" in terms of a simple primitive, show it is equivalent to the ability to send a classical message with a unitary or isometric operation, and use it to relate other resources in quantum information theory. Using coherent ... More
Applications of coherent classical communication and the Schur transform to quantum information theoryDec 30 2005Quantum mechanics has led not only to new physical theories, but also a new understanding of information and computation. Quantum information began by yielding new methods for achieving classical tasks such as factoring and key distribution but also suggests ... More
Scalar Casimir effect with non-local boundary conditionsApr 13 2006Apr 18 2006Non-local boundary conditions have been considered in theoretical high-energy physics with emphasis on one-loop quantum cosmology, one-loop conformal anomalies, Bose-Einstein condensation models and spectral branes. We have therefore studied the Wightman ... More
Low-depth gradient measurements can improve convergence in variational hybrid quantum-classical algorithmsJan 16 2019A broad class of hybrid quantum-classical algorithms known as "variational algorithms" have been proposed in the context of quantum simulation, machine learning, and combinatorial optimization as a means of potentially achieving a quantum speedup on a ... More
Determinants Containing Powers of Generalized Fibonacci NumbersDec 22 2015Jul 30 2016We study determinants of matrices whose entries are powers of Fibonacci numbers. We then extend the results to include entries that are powers of generalized Fibonacci numbers defined as a second-order linear recurrence relation. These studies have led ... More
An analogue of the Robinson-Schensted-Knuth correspondence and non-symmetric Cauchy kernels for truncated staircasesOct 01 2013Nov 26 2014We prove a restriction of an analogue of the Robinson--Schensted--Knuth correspondence for semi-skyline augmented fillings, due to Mason, to multisets of cells of a staircase possibly truncated by a smaller staircase at the upper left end corner, or at ... More
Analysis of Social Voting Patterns on DiggJun 11 2008The social Web is transforming the way information is created and distributed. Blog authoring tools enable users to publish content, while sites such as Digg and are used to distribute content to a wider audience. With content fast becoming ... More
Search for top partners with charge 5e/3Sep 09 2013May 01 2014A feasibility study of searches for top partners with charge 5e/3 at the upgraded Large Hadron Collider is performed. The discovery potential and exclusion limits are presented using integrated luminosities of 300 fb$^{-1}$ and 3000 fb$^{-1}$ at center-of-mass ... More
Casimir effect with non-local boundary conditionsDec 05 2005Mar 16 2006Non-local boundary conditions have been considered in theoretical high-energy physics with emphasis on one-loop quantum cosmology, one-loop conformal anomalies, Bose-Einstein condensation models and spectral branes. In the present paper, for the first ... More
Enhanced Rashba effect for hole states in a quantum dotSep 17 2009Sep 21 2009The effect of Rashba spin-orbit (SO) interaction on the hole states in a quantum dot is studied in the presence of an external magnetic field. We demonstrate here that the Rashba SO coupling has a profound effect on the energy spectrum of the holes revealing ... More
Coevolutionary networks of reinforcement-learning agentsAug 05 2013This paper presents a model of network formation in repeated games where the players adapt their strategies and network ties simultaneously using a simple reinforcement-learning scheme. It is demonstrated that the coevolutionary dynamics of such systems ... More
Phase Transformation in Self-Organized Carbon TribolayersMar 11 2016The simplest way to obtain thin carbon layers is to draw or rub with a graphite rod. During rubbing, forces of friction acting in graphite/substrate tribological system cause drastic changes in the structure of the interface stratum developing thereby ... More
Convergence of Alternating Least Squares Optimisation for Rank-One Approximation to High Order TensorsMar 18 2015The approximation of tensors has important applications in various disciplines, but it remains an extremely challenging task. It is well known that tensors of higher order can fail to have best low-rank approximations, but with an important exception ... More
Exact universality from any entangling gate without inversesJun 03 2008This note proves that arbitrary local gates together with any entangling bipartite gate V are universal. Previously this was known only when access to both V and V^{-1} was given, or when approximate universality was demanded.
Why now is the right time to study quantum computingDec 30 2014Quantum computing is a good way to justify difficult physics experiments. But until quantum computers are built, do computer scientists need to know anything about quantum information? In fact, quantum computing is not merely a recipe for new computing ... More
On Maximum a Posteriori Estimation of Hidden Markov ProcessesJun 10 2009We present a theoretical analysis of Maximum a Posteriori (MAP) sequence estimation for binary symmetric hidden Markov processes. We reduce the MAP estimation to the energy minimization of an appropriately defined Ising spin model, and focus on the performance ... More
A study of Feshbach resonances and the unitary limit in a model of strongly correlated nucleonsMar 05 2010A model of strongly interacting and correlated hadrons is developed. The interaction used contains a long range attraction and short range repulsive hard core. Using this interaction and various limiting situations of it, a study of the effect of bound ... More
Cascading Dynamics in Modular NetworksMar 13 2008In this paper we study a simple cascading process in a structured heterogeneous population, namely, a network composed of two loosely coupled communities. We demonstrate that under certain conditions the cascading dynamics in such a network has a two--tiered ... More
Polarization of the Fulling-Rindler vacuum by uniformly accelerated mirrorOct 03 2001Positive frequency Wightman function and vacuum expectation values of the energy-momentum tensor are computed for a massive scalar field with general curvature coupling parameter and satisfying Robin boundary condition on a uniformly accelerated infinite ... More
Approximate unitary $t$-designs by short random quantum circuits using nearest-neighbor and long-range gatesSep 18 2018We prove that $poly(t) \cdot n^{1/D}$-depth local random quantum circuits with two qudit nearest-neighbor gates on a $D$-dimensional lattice with n qudits are approximate $t$-designs in various measures. These include the "monomial" measure, meaning that ... More
Sects and lattice paths over the Lagrangian GrassmannianMar 18 2019We examine Borel subgroup orbits in the classical symmetric space of type CI, which are parametrized by skew symmetric (n, n)-clans. We describe bijections between such clans, certain weighted lattice paths, and pattern-avoiding signed involutions, and ... More
NW-SE expansions of non-symmetric Cauchy kernels on near staircases and growth diagramsDec 01 2014Lascoux has given a triangular version of the Cauchy identity where Schur polynomials are replaced by Demazure characters and Demazure atoms. He has then used the staircase expansion to recover expansions for all Ferrers shapes, where the Demazure characters ... More
The Church of the Symmetric SubspaceAug 29 2013The symmetric subpace has many applications in quantum information theory. This review article begins by explaining key background facts about the symmetric subspace from a quantum information perspective. Then we review, and in some places extend, work ... More
Review of Quantum Algorithms for Systems of Linear EquationsDec 30 2014This article reviews the 2008 quantum algorithm for linear systems of equations due to Harrow, Hassidim and Lloyd, as well as some of the followup and related work. It was submitted to the Springer Encyclopedia of Algorithms.
Entanglement spread and clean resource inequalitiesSep 08 2009Oct 27 2013This article will examine states that superpose different amounts of entanglement and protocols that run in superposition but generate or consume different amounts of entanglement. In both cases we find a uniquely quantum difficulty: entanglement cannot ... More
Quantum expanders from any classical Cayley graph expanderSep 07 2007Oct 09 2007We give a simple recipe for translating walks on Cayley graphs of a group G into a quantum operation on any irrep of G. Most properties of the classical walk carry over to the quantum operation: degree becomes the number of Kraus operators, the spectral ... More
Adaptive Boolean Networks and Minority Games with Time--Dependent CapacitiesJul 16 2004In this paper we consider a network of boolean agents that compete for a limited resource. The agents play the so called Generalized Minority Game where the capacity level is allowed to vary externally. We study the properties of such a system for different ... More
Spin interactions in a quantum dot containing a magnetic impurityJul 22 2010The electron and hole states in a CdTe quantum dot containing a single magnetic impurity in an external magnetic field are investigated, using the multiband approximation which includes the heavy hole-light hole coupling effects. The electron-hole spin ... More
Eigenvalues and eigenstates of the s ell_q(2)-invariant Universal R-operator defined for cyclic representations at roots of unityAug 13 2002Sep 03 2002The s ell_q(2) representations are realized in the space of polynomials for general and exceptional values of deformation parameter q and on finite set of theta-functions for cyclic representation corresponding to q^N = +/- 1, which are a natural extension ... More
Iterative construction of $U_q (s\ell (n+1)) $ representations and Lax matrix factorisationMay 30 2008Jun 06 2008The construction of a generic representation of $g\ell(n+1)$ or of the trigonomentric deformation of its enveloping algebra known as algebraic induction is conveniently formulated in term of Lax matrices. The Lax matrix of the constructed representation ... More
Baxter operators for arbitrary spinJun 24 2011Sep 16 2011We construct Baxter operators for the homogeneous closed $\mathrm{XXX}$ spin chain with the quantum space carrying infinite or finite dimensional $s\ell_2$ representations. All algebraic relations of Baxter operators and transfer matrices are deduced ... More
Baxter operators with deformed symmetryNov 13 2012Baxter operators are constructed for quantum spin chains with deformed $s\ell_2$ symmetry. The parallel treatment of Yang-Baxter operators for the cases of undeformed, trigonometrically and elliptically deformed symmetries presented earlier and relying ... More
Integrable XYZ Model with Staggered Anisotropy ParameterNov 26 2001We apply to the XYZ model the technique of construction of integrable models with staggered parameters, presented recently for the XXZ case. The solution of modified Yang-Baxter equations is found and the corresponding integrable zig-zag ladder Hamiltonian ... More
Fermionisation of the Spin-S Uimin-Lai-Sutherland Model: Generalisation of Supersymmetric t-J Model to Spin-SSep 29 1999The spin-1 Uimin-Lai-Sutherland (ULS) isotropic chain model is expressed in terms of fermions and the equivalence of the fermionic representation to the supersymmetric t-J model is established directly at the level of Hamiltonians.The spin-S ULS model ... More
Quantum Supremacy through the Quantum Approximate Optimization AlgorithmFeb 24 2016The Quantum Approximate Optimization Algorithm (QAOA) is designed to run on a gate model quantum computer and has shallow depth. It takes as input a combinatorial optimization problem and outputs a string that satisfies a high fraction of the maximum ... More
Testing product states, quantum Merlin-Arthur games and tensor optimisationJan 04 2010Nov 04 2012We give a test that can distinguish efficiently between product states of n quantum systems and states which are far from product. If applied to a state psi whose maximum overlap with a product state is 1-epsilon, the test passes with probability 1-Theta(epsilon), ... More
SectsOct 31 2018By explicitly describing a cellular decomposition we determine the Borel invariant cycles that generate the Chow groups of the quotient of a reductive group by a Levi subgroup. For illustrations we consider the variety of polarizations $\mbf{SL}_n / \mbf{S}(\mbf{GL}_p\times ... More
Local Hamiltonians Whose Ground States are Hard to ApproximateOct 07 2015Nov 21 2016Ground states of local Hamiltonians can be generally highly entangled: any quantum circuit that generates them (even approximately) must be sufficiently deep to allow coupling (entanglement) between any pair of qubits. Until now this property was not ... More
Scalable cavity quantum electrodynamics system for quantum computingJul 18 2015We introduce a new scalable cavity quantum electrodynamics platform which can be used for quantum computing. This system is composed of coupled photonic crystal (PC) cavities which their modes lie on a Dirac cone in the whole super crystal band structure. ... More
Novel variational approach for analysis of photonic crystal slabsFeb 12 2015Apr 04 2015We propose a new method based on variational principle for analysis of photonic crystal (PC) slabs. Most of the methods used today treat PC slab as a three-dimensional (3D) crystal and this makes them very time and/or memory consuming. In this method ... More
How many copies are needed for state discrimination?Jun 15 2006Given a collection of states (rho_1, ..., rho_N) with pairwise fidelities F(rho_i, rho_j) <= F < 1, we show the existence of a POVM that, given rho_i^{otimes n}, will identify i with probability >= 1-epsilon, as long as n>=2(log N/eps)/log (1/F). This ... More
Universality of EPR pairs in Entanglement-Assisted Communication Complexity, and the Communication Cost of State ConversionFeb 20 2019Entanglement assistance is known to reduce the quantum communication complexity of evaluating functions with distributed inputs. But does the type of entanglement matter, or are EPR pairs always sufficient? This is a natural question because in several ... More
A tight lower bound on the classical communication cost of entanglement dilutionApr 17 2002Jun 28 2002Entanglement concentration requires no classical communication, but the best prior art result for diluting to N copies of a partially entangled state requires an amount of communication on the order of sqrt(N) bits. Our main result is to prove this prior ... More
Maximally Informative Hierarchical Representations of High-Dimensional DataOct 27 2014Jan 31 2015We consider a set of probabilistic functions of some input variables as a representation of the inputs. We present bounds on how informative a representation is about input data. We extend these bounds to hierarchical representations so that we can quantify ... More
Comparative Analysis of Viterbi Training and Maximum Likelihood Estimation for HMMsDec 16 2013We present an asymptotic analysis of Viterbi Training (VT) and contrast it with a more conventional Maximum Likelihood (ML) approach to parameter estimation in Hidden Markov Models. While ML estimator works by (locally) maximizing the likelihood of the ... More
Statistical Tests for Contagion in Observational Social Network StudiesNov 20 2012Apr 15 2013Current tests for contagion in social network studies are vulnerable to the confounding effects of latent homophily (i.e., ties form preferentially between individuals with similar hidden traits). We demonstrate a general method to lower bound the strength ... More
Information-Theoretic Measures of Influence Based on Content DynamicsAug 22 2012Feb 15 2013The fundamental building block of social influence is for one person to elicit a response in another. Researchers measuring a "response" in social media typically depend either on detailed models of human behavior or on platform-specific cues such as ... More
Information Transfer in Social MediaOct 12 2011Recent research has explored the increasingly important role of social media by examining the dynamics of individual and group behavior, characterizing patterns of information diffusion, and identifying influential individuals. In this paper we suggest ... More
A Sequence of Relaxations Constraining Hidden Variable ModelsJun 08 2011Jul 20 2011Many widely studied graphical models with latent variables lead to nontrivial constraints on the distribution of the observed variables. Inspired by the Bell inequalities in quantum mechanics, we refer to any linear inequality whose violation rules out ... More
Vacuum densities and zero-point energy for fields obeying Robin conditions on cylindrical surfacesJan 24 2001The Casimir effect for general Robin conditions on the surface of a cylinder in $D$-spacetime dimensions is studied for massive scalar field with general curvature coupling. The energy distribution and vacuum stress are investigated. We separate volumic ... More
Simulated Quantum Annealing Can Be Exponentially Faster than Classical Simulated AnnealingJan 12 2016Jun 23 2016Simulated Quantum Annealing (SQA) is a Markov Chain Monte-Carlo algorithm that samples the equilibrium thermal state of a Quantum Annealing (QA) Hamiltonian. In addition to simulating quantum systems, SQA has also been proposed as another physics-inspired ... More
Theoretical Insights into Mechanisms of Stochastic Gating in Channel-Facilitated Molecular TransportDec 18 2018Molecular motion through pores plays a crucial role in various natural and industrial processes. One of the most fascinating features of biological channel-facilitated transport is a stochastic gating process, when the channels dynamically fluctuate between ... More
K-Bit-Swap: A New Operator For Real-Coded Evolutionary AlgorithmsApr 22 2016There has been a variety of crossover operators proposed for Real-Coded Genetic Algorithms (RCGAs), which recombine values from the same location in pairs of strings. In this article we present a recombination operator for RC- GAs that selects the locations ... More
Sequential measurements, disturbance and property testingJul 12 2016We describe a procedure which, given access to one copy of a quantum state and a sequence of two-outcome measurements, can distinguish between the case that at least one of the measurements accepts the state with high probability, and the case that all ... More
Superpolynomial speedups based on almost any quantum circuitApr 30 2008May 02 2008The first separation between quantum polynomial time and classical bounded-error polynomial time was due to Bernstein and Vazirani in 1993. They first showed a O(1) vs. Omega(n) quantum-classical oracle separation based on the quantum Hadamard transform, ... More
Extremal eigenvalues of local HamiltoniansJul 02 2015Feb 16 2016We apply classical algorithms for approximately solving constraint satisfaction problems to find bounds on extremal eigenvalues of local Hamiltonians. We consider spin Hamiltonians for which we have an upper bound on the number of terms in which each ... More
Rapid mixing of path integral Monte Carlo for 1D stoquastic HamiltoniansDec 05 2018Path integral quantum Monte Carlo (PIMC) is a method for estimating thermal equilibrium properties of stoquastic quantum spin systems by sampling from a classical Gibbs distribution using Markov chain Monte Carlo. The PIMC method has been widely used ... More
Baxter operators for arbitrary spin IIJul 04 2011Sep 07 2011This paper presents the second part of our study devoted to the construction of Baxter operators for the homogeneous closed XXX spin chain with the quantum space carrying infinite or finite-dimensional $s\ell_2$ representations. We consider the Baxter ... More
Trace Anomalies and Cocycles of Weyl and Diffeomorphisms GroupsNov 08 1994The general structure of trace anomaly, suggested recently by Deser and Shwimmer, is argued to be the consequence of the Wess-Zumino consistency condition. The response of partition function on a finite Weyl transformation, which is connected with the ... More
Area-preserving structure of 2d-gravityJan 10 1994The effective action for 2d-gravity with manifest area-preserving invariance is obtained in the flat and in the general gravitational background. The cocyclic properties of the last action are proved, and generalizations on higher dimensions are discussed. ... More
Bidirectional coherent classical communicationDec 16 2004May 12 2005A unitary interaction coupling two parties enables quantum communication in both the forward and backward directions. Each communication capacity can be thought of as a tradeoff between the achievable rates of specific types of forward and backward communication. ... More