Results for "Abhishek Juyal"

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Colossal enhancement of electrical conductivity in Y2Ir2O7 nanoparticlesNov 17 2016We present a comparative study of the magnetic and electrical properties of polycrystalline and nanocrystalline Y2Ir2O7, the latter prepared using a new chemical route. We find that reduction in particle size leads to enhanced ferromagnetism and orders ... More
Negative longitudinal magnetoresistance in the density wave phase of Y$_2$Ir$_2$O$_7$Feb 08 2018The ground state of nanowires of single crystalline Pyrochlore Y$_2$Ir$_2$O$_7$ is a density wave. Application of a {\it transverse} magnetic field increases the threshold electric field for the collective de-pinning of the density wave state at low temperature, ... More
Evidence of density waves in single crystalline nanowires of Pyrochlore IridatesMar 03 2017We present experimental evidence of emergent density wave instability in single crystalline low dimensional wires of Yittrium based Pyrochlore Iridates. We demonstrate electric field induced nonlinear hysteretic switching of the density wave at low temperature, ... More
Aspects of Integrability in N =4 SYMAug 21 2007Various recently developed connections between supersymmetric Yang-Mills theories in four dimensions and two dimensional integrable systems serve as crucial ingredients in improving our understanding of the AdS/CFT correspondence. In this review, we highlight ... More
Mass-Gaps and Spin Chains for (Super) MembranesOct 01 2006We present a method for computing the non-perturbative mass-gap in the theory of Bosonic membranes in flat background spacetimes with or without background fluxes. The computation of mass-gaps is carried out using a matrix regularization of the membrane ... More
Heat conduction in a one-dimensional gas of elastically colliding particles of unequal massesFeb 12 2001We study the nonequlibrium state of heat conduction in a one-dimensional system of hard point particles of unequal masses interacting through elastic collisions. A BBGKY-type formulation is presented and some exact results are obtained from it. Extensive ... More
Ergodicity properties of energy conserving single spin flip dynamics in the XY modelApr 30 1998A single spin flip stochastic energy conserving dynamics for the XY model is considered. We study the ergodicity properties of the dynamics. It is shown that phase space trajectories densely fill the geometrically connected parts of the energy surface. ... More
Predicting Performance of a Face Recognition System Based on Image QualityOct 24 2015In this dissertation, we present a generative model to capture the relation between facial image quality features (like pose, illumination direction, etc) and face recognition performance. Such a model can be used to predict the performance of a face ... More
Smallest Ellipsoid Containing $p$-Sum of Ellipsoids with Application to Reachability AnalysisJun 20 2018Aug 28 2018We study the problem of ellipsoidal bounding of convex set-valued data, where the convex set is obtained by the $p$-sum of finitely many ellipsoids, for any real $p\geq 1$. The notion of $p$-sum appears in the Brunn-Minkowski-Firey theory in convex analysis, ... More
Sup-norms of eigenfunctions in the level aspect for compact arithmetic surfacesDec 04 2018Dec 11 2018Let $D$ be an indefinite quaternion division algebra over $\mathbb{Q}$. We approach the problem of bounding the sup-norms of automorphic forms $\phi$ on $D^\times(\mathbb{A})$ that belong to irreducible automorphic representations and transform via characters ... More
Ancilla Assisted Quantum Information Processing: General protocols and NMR implementationsJan 02 2016While a bit is the fundamental unit of binary classical information, a qubit is the fundamental unit of quantum information. In quantum information processing (QIP), it is customary to call the qubits under study as system qubits, and the additional qubits ... More
On sup-norms of cusp forms of powerful levelApr 11 2014Nov 11 2015Let f be an L^2-normalized Hecke--Maass cuspidal newform of level N and Laplace eigenvalue \lambda. It is shown that |f|_\infty <<_{\lambda, \epsilon} N^{-1/12 + \epsilon} for any \epsilon>0. The exponent is further improved in the case when N is not ... More
On ratios of Petersson norms for Yoshida liftsMar 21 2013Apr 14 2013We prove an algebraicity property for a certain ratio of Petersson norms associated to a Siegel cusp form of degree 2 (and arbitrary level) whose adelization generates a weak endoscopic lift. As a preparation for this, we explicate various features of ... More
Siegel cusp forms of degree 2 are determined by their fundamental Fourier coefficientsJun 25 2011Jan 21 2012We prove that a Siegel cusp form of degree 2 for the full modular group is determined by its set of Fourier coefficients a(S) with 4 det(S) ranging over odd squarefree integers. As a key step to our result, we also prove that a classical cusp form of ... More
Prime density results for Hecke eigenvalues of a Siegel cusp formJul 27 2010Jul 30 2010Let F in S_k(Sp(2g, Z)) be a cuspidal Siegel eigenform of genus g with normalized Hecke eigenvalues mu_F(n). Suppose that the associated automorphic representation pi_F is locally tempered everywhere. For each c>0 we consider the set of primes p for which ... More
Comment on ``Can Disorder Induce a Finite Thermal Conductivity in 1D Lattices?''Jun 18 2001In a recent paper [Phys. Rev. Lett. 86, 63 (2001)], Li et al have reported that the nonequilibrium heat conducting steady state of a disordered harmonic chain is not unique. In this comment we point out that for a large class of stochastic heat baths ... More
Motif Analysis in the Amazon Product Co-Purchasing NetworkDec 18 2010Online stores like Amazon and Ebay are growing by the day. Fewer people go to departmental stores as opposed to the convenience of purchasing from stores online. These stores may employ a number of techniques to advertise and recommend the appropriate ... More
Conformal blocks on a 2-sphere with indistinguishable punctures and implications on black hole entropySep 04 2016The dimensionality of the Hilbert space of a Chern-Simons theory on a 3-fold, in the presence of Wilson lines carrying spin representations, had been counted by using its link with the Wess-Zumino theory, with level $k$, on the 2-sphere with points (to ... More
Thermodynamic partition function from quantum theory for black hole horizons in loop quantum gravityNov 30 2013Sep 22 2016We establish the link between the thermodynamics and the quantum theory of black hole horizons through the construction of the thermodynamic partition function, partly based on some physically plausible arguments, by beginning from the description of ... More
Energy spectrum of black holes : a new viewMar 20 2013Nov 08 2016Energy of a black hole is usually quantized by invoking some area quantization scheme after expressing the energy in terms of the horizon area. However, in this approach one has to quantize the local and asymptotic energy of the black hole separately ... More
A Supersymmetry Preserving Mass-Deformation of N=1 Super Yang-Mills in D=2+1Sep 04 2009Sep 18 2009We construct a massive non-abelian N= 1 SYM theory on R^3. This is achieved by using a non-local gauge and Poincare invariant mass term for gluons due to Nair. The underlying supersymmetry algebra is shown to be a non-central extension of the Poincare ... More
Hybrid sup-norm bounds for Maass newforms of powerful levelSep 24 2015Oct 13 2015Let f be an L^2-normalized Hecke--Maass cuspidal newform of level N, character \chi and Laplace eigenvalue \lambda. Let N_1 denote the smallest integer such that N|N_1^2 and N_0 denote the largest integer such that N_0^2 |N. Let M denote the conductor ... More
Homological Algebra of Heyting modulesDec 15 2018The collection of open sets of a topological space forms a Heyting algebra, which leads to the idea of a Heyting algebra as a generalized topological space. In fact, a sober topological space may be reconstructed from its locale of open sets. This has ... More
Classifying subcategories and the spectrum of a locally noetherian categoryOct 23 2017Let $\mathcal A$ be a locally noetherian Grothendieck category. In this paper, we study subcategories of $\mathcal A$ using subsets of the spectrum $\mathfrak Spec(\mathcal A)$. Along the way, we also develop results in local algebra with respect to the ... More
Min Morse: Approximability & ApplicationsMar 11 2015Apr 08 2015We resolve an open problem posed by Joswig et al. by providing an $\tilde{O}(N)$ time, $O(\log^2(N))$-factor approximation algorithm for the min-Morse unmatched problem (MMUP) Let $\Lambda$ be the no. of critical cells of the optimal discrete Morse function ... More
Variation of rest mass scale in a gravitational fieldMay 01 2019I argue that the rest mass scales associated with different locally flat regions of a curved spacetime differ from each other. If, Planck's constant $(h)$ and the velocity of light in vacuum $(c)$, are considered to be given fundamental (constant) scales ... More
Mass Gap in weakly coupled abelian Higgs on a unit latticeNov 01 2018The proof of Higgs mechanism in a weakly coupled lattice gauge theory in $d \geqslant 2$ is revisited. A new power series cluster expansion is applied and the mass gap is shown to exist for the observable $F_{\mu\nu}$.
Work distribution functions in polymer stretching experimentsSep 05 2004We compute the distribution of the work done in stretching a Gaussian polymer, made of N monomers, at a finite rate. For a one-dimensional polymer undergoing Rouse dynamics, the work distribution is a Gaussian and we explicitly compute the mean and width. ... More
Heat conduction in the disordered harmonic chain revisitedMay 04 2001A general formulation is developed to study heat conduction in disordered harmonic chains with arbitrary heat baths that satisfy the fluctuation-dissipation theorem. A simple formal expression for the heat current J is obtained, from which its asymptotic ... More
Conformal blocks on a 2-sphere with indistinguishable punctures and implications on black hole entropySep 04 2016Oct 06 2016The dimensionality of the Hilbert space of a Chern-Simons theory on a 3-fold, in the presence of Wilson lines carrying spin representations, had been counted by using its link with the Wess-Zumino theory, with level $k$, on the 2-sphere with points (to ... More
Stability of Quantum Isolated Horizon : A Local Observer's ViewDec 15 2011Feb 28 2013It is shown that a Quantum Isolated Horizon(QIH), as observed by a local observer, is locally unstable as a thermodynamic system. The result is derived in two different ways. Firstly, the specific heat of the QIH is shown to be negative definite through ... More
Twitter and Polls: Analyzing and estimating political orientation of Twitter users in India General #Elections2014Jun 19 2014This year (2014) in the month of May, the tenure of the 15th Lok Sabha was to end and the elections to the 543 parliamentary seats were to be held. A whooping $5 billion were spent on these elections, which made us stand second only to the US Presidential ... More
Mass Deformations of Super Yang-Mills Theories in D= 2+1, and Super-Membranes: A NoteJun 26 2008Mass deformations of supersymmetric Yang-Mills theories in three spacetime dimensions are considered. The gluons of the theories are made massive by the inclusion of a non-local gauge and Poincare invariant mass term due to Alexanian and Nair, while the ... More
Open Spin Chains in Super Yang-Mills at Higher Loops: Some Potential Problems with IntegrabilityMar 09 2006May 14 2006The super Yang-Mills duals of open strings attached to maximal giant gravitons are studied in perturbation theory. It is shown that non-BPS baryonic excitations of the gauge theory can be studied within the paradigm of open quantum spin chains even beyond ... More
DeGroot-Friedkin Map in Opinion Dynamics is Mirror DescentDec 29 2018Jan 07 2019We provide a variational interpretation of the DeGroot-Friedkin map in opinion dynamics. Specifically, we show that the nonlinear dynamics for the DeGroot-Friedkin map can be viewed as mirror descent on the standard simplex with the associated Bregman ... More
Noetherian Schemes over abelian symmetric monoidal categoriesOct 13 2014Jan 27 2016In this paper, we develop basic results of algebraic geometry over abelian symmetric monoidal categories. Let $A$ be a commutative monoid object in an abelian symmetric monoidal category $(\mathbf C,\otimes,1)$ satisfying certain conditions and let $\mathcal ... More
Dennis trace map for certain $K$-groups of categories with cofibrationsDec 18 2014Let $\mathcal C$ be a small category with cofibrations. In this paper, we define the $K$-theory and Hochschild homology groups of $\mathcal C$ of order $Y$, where $Y$ is an ordered finite simplicial set with basepoint. Further, we construct the Dennis ... More
Hybrid sup-norm bounds for Maass newforms of powerful levelSep 24 2015Jul 04 2017Let $f$ be an $L^2$-normalized Hecke--Maass cuspidal newform of level $N$, character $\chi$ and Laplace eigenvalue $\lambda$. Let $N_1$ denote the smallest integer such that $N|N_1^2$ and $N_0$ denote the largest integer such that $N_0^2 |N$. Let $M$ ... More
Determination of modular forms by fundamental Fourier coefficientsJul 30 2012Dec 17 2012This article is a research exposition based on the author's talk at the International Colloquium on Automorphic Representations and L-Functions, 2012, held at TIFR, Mumbai. We consider some special cases of the following question: when is a natural subset ... More
A relation between multiplicity one and Bocherer's conjectureAug 14 2012Apr 10 2013We show that a weak form of the generalized Bocherer's conjecture implies multiplicity one for Siegel cusp forms of degree 2.
Thermodynamics of Quantum Isolated Horizons with model HamiltoniansMar 20 2013Jul 17 2014Following a recent proposal, we consider the most general structure possible for the Hamiltonian operator associated with the Quantum Isolated Horizon(QIH) with explanations of the underlying physical motivations. An extensive thermodynamic analysis with ... More
Proof of Bekenstein-Mukhanov ansatz in loop quantum gravitySep 22 2016A simple proof of Bekenstein-Mukhanov(BM) ansatz is given within the loop quantum gravity(LQG) framework. The macroscopic area of an equilibrium black hole horizon indeed manifests a linear quantization. The quantum number responsible for this discreteness ... More
Black Hole Entropy from indistinguishable quantum geometric excitationsFeb 06 2014Nov 21 2015In loop quantum gravity, the quantum geometry of a black hole horizon consist of discrete non-perturbative quantum geometric excitations (or punctures) labeled by spins, which are responsible for the quantum area of the horizon. If these punctures are ... More
Comment on `Black hole entropy and isolated horizon thermodynamics'Apr 12 2012Nov 04 2013There is a deep underlying problem in the model dependent thermodynamic analysis of black holes shown in the above quoted paper. In this method one can only find out the canonical entropy of the black hole but not the `microcanonical' entropy. Besides ... More
Heat transport in disordered quantum harmonic oscillator chainsOct 21 2002Jan 21 2003We study heat conduction in quantum disordered harmonic chains connected to general heat reservoirs which are modeled as infinite collection of oscillators. Formal exact expressions for the thermal current are obtained and it is shown that, in some special ... More
Comment on ``A simple one-dimensional model of heat conduction which obeys Fourier's law''Mar 05 2002A finite Green-Kubo thermal conductivity in a one-dimensional momentum conserving system was reported recently by Garrido et al [Phys. Rev. Lett., vol. 86, 5486 (2001)]. We first comment on the apparent contradiction with an earlier result of Prosen and ... More
DeGroot-Friedkin Map in Opinion Dynamics is Mirror DescentDec 29 2018Feb 17 2019We provide a variational interpretation of the DeGroot-Friedkin map in opinion dynamics. Specifically, we show that the nonlinear dynamics for the DeGroot-Friedkin map can be viewed as mirror descent on the standard simplex with the associated Bregman ... More
On Noetherian schemes over $(\mathcal C,\otimes,1)$ and the category of quasi-coherent sheavesMay 06 2015Jan 05 2016Let $(\mathcal C,\otimes,1)$ be an abelian symmetric monoidal category satisfying certain conditions and let $X$ be a scheme over $(\mathcal C,\otimes,1)$ in the sense of To\"en and Vaqui\'{e}. In this paper we show that when $X$ is quasi-compact and ... More
Quasimodular Hecke algebras and Hopf actionsNov 12 2014Sep 03 2015Let $\Gamma=\Gamma(N)$ be a principal congruence subgroup of $SL_2(\mathbb Z)$. In this paper, we extend the theory of modular Hecke algebras due to Connes and Moscovici to define the algebra $\mathcal Q(\Gamma)$ of quasimodular Hecke operators of level ... More
The $q$-analog of higher order Hochschild homology and the Lie derivativeNov 03 2014Let $A$ be a commutative algebra over $\mathbb C$. Given a pointed simplicial finite set $Y$ and $q\in \mathbb C$ a primitive $N$-th root of unity, we define the $q$-Hochschild homology groups of $A$ of order $Y$. When $D$ is a derivation on $A$, we construct ... More
Optimal Morse functions and $H(\mathcal{M}^2,\mathbb{A})$ in $\tilde{O}(N)$ timeMay 09 2015In this work, we design a nearly linear time discrete Morse theory based algorithm for computing homology groups of 2-manifolds, thereby establishing the fact that computing homology groups of 2-manifolds is remarkably easy. Unlike previous algorithms ... More
Improvised Salient Object Detection and ManipulationNov 10 2015In case of salient subject recognition, computer algorithms have been heavily relied on scanning of images from top-left to bottom-right systematically and apply brute-force when attempting to locate objects of interest. Thus, the process turns out to ... More
Pullbacks of Eisenstein series from GU(3,3) and critical L-values for GSp(4) X GL(2)Apr 25 2009Oct 02 2009Let F be a genus two Siegel newform and g a classical newform, both of squarefree levels and of equal weight l. We prove a pullback formula for certain Eisenstein series -- thus generalizing a construction of Shimura -- and use this to derive an explicit ... More
One Shot Joint Colocalization and CosegmentationMay 17 2017This paper presents a novel framework in which image cosegmentation and colocalization are cast into a single optimization problem that integrates information from low level appearance cues with that of high level localization cues in a very weakly supervised ... More
On some spectral spaces associated to tensor triangulated categoriesOct 26 2016We consider a closure operator $c$ of finite type on the space $SMod(\mathcal M)$ of thick $\mathcal K$-submodules of a triangulated category $\mathcal M$ that is a module over a tensor triangulated category $(\mathcal K,\otimes,1)$. Our purpose is to ... More
The Microcanonical Entropy of Quantum Isolated Horizon, `quantum hair' $N$ and the Barbero-Immirzi parameter fixationMay 15 2012Mar 11 2014{\it If} the total number of punctures($N$) of a quantum isolated horizon is considered to be a macroscopic parameter alongside the Chern-Simons level($k$) or equivalently classical area$(A_{cl})$ a strict analysis of the {\it microcanonical} ensemble ... More
Field dynamics on the trapping horizon in Vaidya spacetimeJul 20 2016In this article, we shed some light on the field theoretic aspect of a generic {\it trapping horizon}(TH) with a view to probe beyond the Chern-Simons interpretation of an equilibrium TH, namely {\it isolated horizon}(IH) in the gauge theoretic formulation ... More
Heat Transport in low-dimensional systemsAug 24 2008Nov 19 2008Recent results on theoretical studies of heat conduction in low-dimensional systems are presented. These studies are on simple, yet nontrivial, models. Most of these are classical systems, but some quantum-mechanical work is also reported. Much of the ... More
Face Shape and Reflectance Acquisition using a Multispectral Light StageMay 18 2011In this thesis, we discuss the design and calibration (geometric and radiometric) of a novel shape and reflectance acquisition device called the "Multispectral Light Stage". This device can capture highly detailed facial geometry (down to the level of ... More
On the Parameterized Computation of Minimum Volume Outer Ellipsoid of Minkowski Sum of EllipsoidsMar 21 2018Jun 22 2018We consider the problem of computing certain parameterized minimum volume outer ellipsoidal (MVOE) approximation of the Minkowski sum of a finite number of ellipsoids. We clarify connections among several parameterizations available in the literature, ... More
Nonparametric Bayes Classification via Learning of Affine SubspacesJan 04 2013The goal of this presentation is to build an efficient non-parametric Bayes classifier in the presence of large numbers of predictors. When analyzing such data, parametric models are often too inflexible while non-parametric procedures tend to be non-robust ... More
Chow groups of ind-schemes and extensions of Saito's filtrationNov 07 2013Jun 16 2015Let $K$ be a field of characteristic zero and let $Sm/K$ be the category of smooth and separated schemes over $K$. For an ind-scheme $\mathcal X$ (and more generally for any presheaf of sets on $Sm/K$), we define its Chow groups $\{CH^p(\mathcal X)\}_{p\in ... More
Supervised Classification of RADARSAT-2 Polarimetric Data for Different Land FeaturesAug 01 2016The pixel percentage belonging to the user defined area that are assigned to cluster in a confusion matrix for RADARSAT-2 over Vancouver area has been analysed for classification. In this study, supervised Wishart and Support Vector Machine (SVM) classifiers ... More
Novel fluctuations at constrained interfacesJan 25 2006In this study we try to answer the qustion : What happens when explicit constraints are introduced such that the low energy, long wavelength modes of a system are unavailable ? This question has assumed some importance in recent years due to the advent ... More
Large values of newforms on GL(2) with highly ramified central characterDec 17 2014Sep 23 2015We give a lower bound for the sup-norm of an $L^2$-normalized newform in an irreducible, unitary, cuspidal representation $\pi$ of $GL_2$ over a number field. When the central character of $\pi$ is sufficiently ramified, this bound improves upon the trivial ... More
Sup-norms of eigenfunctions in the level aspect for compact arithmetic surfacesDec 04 2018May 08 2019Let $D$ be an indefinite quaternion division algebra over $\mathbb{Q}$. We approach the problem of bounding the sup-norms of automorphic forms $\phi$ on $D^\times(\mathbb{A})$ that belong to irreducible automorphic representations and transform via characters ... More
Existence and Multiplicity of a Nonhomogeneous Polyharmonic Equation With Critical Exponential Growth in Even DimensionApr 13 2015In this paper we study the existence of at least two positive weak solutions for an inhomogeneous fourth order equation with Navier boundary data involving nonlinearities of critical growth with a bifurcation parameter $\lambda$ in $\mathbb{R}^{2m}$. ... More
Foreground Clustering for Joint Segmentation and Localization in Videos and ImagesNov 26 2018This paper presents a novel framework in which video/image segmentation and localization are cast into a single optimization problem that integrates information from low level appearance cues with that of high level localization cues in a very weakly ... More
Sur la catégorie dérivée des faisceaux tordusOct 27 2014Soit $X$ un sch\'ema quasi-compact et s\'epar\'e et soit $\alpha\in \check{C}^2(X, \mathcal O_X^*)$ un cocycle de C\v{e}ch. Nous consid\'erons la cat\'egorie d\'eriv\'ee $D(QCoh(X,\alpha))$ des faisceaux quasi-coh\'erents sur $X$ tordu par $\alpha$. Soit ... More
A nonparametric sequential test for online randomized experimentsOct 08 2016Oct 14 2016We propose a nonparametric sequential test that aims to address two practical problems pertinent to online randomized experiments: (i) how to do a hypothesis test for complex metrics; (ii) how to prevent type $1$ error inflation under continuous monitoring. ... More
Recursive Secret Sharing for Distributed Storage and Information HidingJan 19 2010This paper presents a recursive computational multi-secret sharing technique that hides k-2 secrets of size b each into n shares of a single secret S of size b, such that any k of the n shares suffice to recreate the secret S as well as all the hidden ... More
Autocatalysis in Reaction NetworksSep 16 2013Aug 06 2014The persistence conjecture is a long-standing open problem in chemical reaction network theory. It concerns the behavior of solutions to coupled ODE systems that arise from applying mass-action kinetics to a network of chemical reactions. The idea is ... More
Exact probability distribution for the two-tag displacement in single-file motionJun 05 2015We consider a gas of point particles moving on the one-dimensional line with a hard-core inter-particle interaction that prevents particle crossings --- this is usually referred to as single-file motion. The individual particle dynamics can be arbitrary ... More
Work distribution functions for hysteresis loops in a single-spin systemAug 01 2005Dec 22 2005We compute the distribution of the work done in driving a single Ising spin with a time-dependent magnetic field. Using Glauber dynamics we perform Monte-Carlo simulations to find the work distributions at different driving rates. We find that in general ... More
Topological Phases near a Triple DegeneracyNov 07 2001We study the pattern of three state topological phases that appear in systems with real Hamiltonians and wave functions. We give a simple geometric construction for representing these phases. We then apply our results to understand previous work on three ... More
Hidden symmetries in deformed microwave resonatorsFeb 26 2002Oct 15 2002We explain the ``Hidden symmetries'' observed in wavefunctions of deformed microwave resonators in recent experiments.We also predict that other such symmetries can be seen in microwave resonators.
Stochastic pump of interacting particlesDec 28 2010We consider the overdamped motion of Brownian particles, interacting via particle exclusion, in an external potential that varies with time and space. We show that periodic potentials that maintain specific position-dependent phase relations generate ... More
Equilibration problem for the generalized Langevin equationApr 06 2006Aug 24 2007We consider the problem of equilibration of a single oscillator system with dynamics given by the generalized Langevin equation. It is well-known that this dynamics can be obtained if one considers a model where the single oscillator is coupled to an ... More
Local Partial Clique Covers for Index CodingMar 08 2016Apr 29 2016Index coding, or broadcasting with side information, is a network coding problem of most fundamental importance. In this problem, given a directed graph, each vertex represents a user with a need of information, and the neighborhood of each vertex represents ... More
On the Incentive to Deviate in Core Selecting Combinatorial AuctionsSep 10 2012Recent spectrum auctions in the United Kingdom, and some proposals for future auctions of spectrum in the United States, are based on preliminary price discovery rounds, followed by calculation of final prices for the winning buyers. For example, the ... More
A Comparative Study of Asynchronous Many-Tasking Runtimes: Cilk, Charm++, ParalleX and AM++Apr 01 2019We evaluate and compare four contemporary and emerging runtimes for high-performance computing(HPC) applications: Cilk, Charm++, ParalleX and AM++. We compare along three bases: programming model, execution model and the implementation on an underlying ... More
A numerical procedure for model reduction using the generalized Langevin equation formalismApr 17 2013The Zwanzig-Mori pro jection formalism is widely used in studying systems with many degrees of freedom. Recently Xing and Kim used the pro jection formalism and derived the generalized Langevin equations (GLEs) for a general stochastic system not necessarily ... More
Supersymmetric Wilson Loops in Diverse DimensionsApr 03 2009Aug 12 2009We consider supersymmetric Wilson loops a la Zarembo in planar supersymmetric Yang-Mills theories in diverse dimensions. Using perturbation theory we show that these loops have trivial vacuum expectation values to second order in the 't Hooft coupling. ... More
Anomalous transport and current fluctuations in a model of diffusing Levy walkersAug 26 2013A Levy walk is a non-Markovian stochastic process in which the elementary steps of the walker consist of motion with constant speed in randomly chosen directions and for a random period of time. The time of flight is chosen from a long-tailed distribution ... More
Additivity Principle in High-dimensional Deterministic SystemsJun 15 2011Dec 22 2011The additivity principle (AP), conjectured by Bodineau and Derrida [Phys. Rev. Lett. vol.92, 180601 (2004)], is discussed for the case of heat conduction in three-dimensional disordered harmonic lattices to consider the effects of deterministic dynamics, ... More
Chiral Haldane phases of SU(N) quantum spin chains in the adjoint representationDec 16 2015Gapped quantum spin chains with symmetry PSU(N)=SU(N)/Z(N) are known to possess N distinct symmetry protected topological phases. Besides the trivial phase, there are N-1 Haldane phases which are distinguished by the occurrence of massless boundary spins. ... More
Profile driven interfaces in 1 + 1 dimensions : periodic steady states, dynamical melting and detachmentJul 05 2002We study the steady state structure and dynamics of a 2-d Ising interface placed in an inhomogeneous external field with a sigmoidal profile which moves with velocity $v_{e}$. In the strong coupling limit the problem maps onto an assymmetric exclusion ... More
The singular bivariate quartic tracial moment problemNov 02 2016Dec 19 2017The (classical) truncated moment problem, extensively studied by Curto and Fialkow, asks to characterize when a finite sequence of real numbers indexes by words in commuting variables can be represented with moments of a positive Borel measure $\mu$ on ... More
Sup-norms of eigenfunctions in the level aspect for compact arithmetic surfaces, IIMay 15 2019We obtain for the first time an improvement over the local bound in the depth aspect for sup-norms of newforms on an indefinite quaternion division algebra over $\mathbb{Q}$. A central role in our method is played by the decay of local matrix coefficients. ... More
Hilbert modular forms of weight 1/2 and theta functionsMar 26 2008Serre and Stark found a basis for the space of modular forms of weight 1/2 in terms of theta series. In this paper, we generalize their result - under certain mild restrictions on the level and character - to the case of weight 1/2 Hilbert modular forms ... More
Top-flavored dark matter and the forward-backward asymmetryMar 02 2013We propose a simple model where dark matter (DM) carries top flavor and couples to the Standard Model through the top quark within a framework of minimal flavor violation (MFV). Top-flavored DM can explain the anomalous top forward-backward asymmetry ... More
Exact and Heuristic Algorithms for Semi-Nonnegative Matrix FactorizationOct 27 2014May 08 2015Given a matrix $M$ (not necessarily nonnegative) and a factorization rank $r$, semi-nonnegative matrix factorization (semi-NMF) looks for a matrix $U$ with $r$ columns and a nonnegative matrix $V$ with $r$ rows such that $UV$ is the best possible approximation ... More
Revenue Optimal Auction for Single-Minded BuyersMay 06 2010Sep 13 2010We study the problem of characterizing revenue optimal auctions for single-minded buyers. Each buyer is interested only in a specific bundle of items and has a value for the same. Both his bundle and its value are his private information. The bundles ... More
Language to Specify Syntax-Guided Synthesis ProblemsMay 22 2014We present a language to specify syntax guided synthesis (SyGuS) problems. Syntax guidance is a prominent theme in contemporary program synthesis approaches, and SyGuS was first described in [1]. This paper describes concretely the input format of a SyGuS ... More
Charged Quantum Black Holes : Thermal Stability CriterionAug 23 2011Jun 06 2012A criterion of thermal stability is derived for electrically charged quantum} black holes having large horizon area (compared to Planck area), as an inequality between the mass of the black hole and its microcanonical entropy. The derivation is based ... More
Lefschetz thimble Monte Carlo for many body theories: application to the repulsive Hubbard model away from half fillingMar 22 2014Recently, a new method, based on stochastic integration on the surfaces of steepest descent of the action, was introduced to tackle the sign problem in quantum field theories. We show how this method can be used in many body theories to perform fully ... More
Bounds on the Rate of Linear Locally Repairable Codes over Small AlphabetsJul 28 2016Locally repairable codes (LRC) have recently been a subject of intense research due to theoretical appeal and their application in distributed storage systems. In an LRC, any coordinate of a codeword can be recovered by accessing only few other coordinates. ... More
Security in Locally Repairable StorageMar 13 2015Aug 12 2016In this paper we extend the notion of {\em locally repairable} codes to {\em secret sharing} schemes. The main problem that we consider is to find optimal ways to distribute shares of a secret among a set of storage-nodes (participants) such that the ... More
The singular bivariate quartic tracial moment problemNov 02 2016The (classical) truncated moment problem, extensively studied by Curto and Fialkow, asks to characterize when a finite sequence of real numbers indexes by words in commuting variables can be represented with moments of a positive Borel measure $\mu$ on ... More
Electron transport in a one dimensional conductor with inelastic scattering by self-consistent reservoirsNov 10 2006Apr 26 2007We present an extension of the work of D'Amato and Pastawski on electron transport in a one-dimensional conductor modeled by the tight binding lattice Hamiltonian and in which inelastic scattering is incorporated by connecting each site of the lattice ... More