Results for "Amit Sharma"

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Symmetric monoidal categories and $Γ$-categoriesNov 28 2018In this paper we construct a symmetric monoidal closed model category of coherently commutative monoidal categories. The main aim of this paper is to establish a Quillen equivalence between a model category of coherently commutative monoidal categories ... More
On the homotopy theory of $\mathbf{G}$ - spacesDec 11 2015The aim of this paper is to show that the most elementary homotopy theory of $\mathbf{G}$-spaces is equivalent to a homotopy theory of simplicial sets over $\mathbf{BG}$, where $\mathbf{G}$ is a fixed group. Both homotopy theories are presented as Relative ... More
Necessary and Probably Sufficient Test for Finding Valid Instrumental VariablesDec 04 2018Can instrumental variables be found from data? While instrumental variable (IV) methods are widely used to identify causal effect, testing their validity from observed data remains a challenge. This is because validity of an IV depends on two assumptions, ... More
Construction of self-dual codes over $\mathbb{Z}_{2^m}$Jul 14 2014Self-dual codes (Type I and Type II codes) play an important role in the construction of even unimodular lattices, and hence in the determination of Jacobi forms. In this paper, we construct both Type I and Type II codes (of higher lengths) over the ring ... More
Distinguishing between Personal Preferences and Social Influence in Online Activity FeedsApr 05 2016Many online social networks thrive on automatic sharing of friends' activities to a user through activity feeds, which may influence the user's next actions. However, identifying such social influence is tricky because these activities are simultaneously ... More
Do Social Explanations Work? Studying and Modeling the Effects of Social Explanations in Recommender SystemsApr 11 2013Recommender systems associated with social networks often use social explanations (e.g. "X, Y and 2 friends like this") to support the recommendations. We present a study of the effects of these social explanations in a music recommendation context. We ... More
Categorification of Dijkgraaf-Witten TheoryNov 01 2015Feb 09 2016The goal of the paper is to categorify Dijkgraaf-Witten theory, aiming at providing foundation for a direct construction of Dijkgraaf-Witten theory as an Extended Topological Quantum Field Theory. The main tool is cohomology with coefficients in a Picard ... More
Explaining Machine Learning Classifiers through Diverse Counterfactual ExplanationsMay 19 2019Post-hoc explanations of machine learning models are crucial for people to understand and act on algorithmic predictions. An intriguing class of explanations is through counterfactuals, hypothetical examples that show people how to obtain a different ... More
On The Non-Gaussian Errors in High-z Supernovae Type Ia DataApr 29 2016Jul 15 2016The nature of random errors in any data set that is Gaussian is a well established fact according to the Central Limit Theorem. Supernovae type Ia data have played a crucial role in major discoveries in cosmology. Unlike in laboratory experiments, astronomical ... More
Studies On Falling Ball ViscometryFeb 07 2012Feb 13 2012A new method of accurate calculation of the coefficient of viscosity of a test liquid from experimentally measured terminal velocity of a ball falling in the test liquid contained in a narrow tube is described. The calculation requires the value of a ... More
Split-door criterion: Identification of causal effects through auxiliary outcomesNov 28 2016Jun 14 2018We present a method for estimating causal effects in time series data when fine-grained information about the outcome of interest is available. Specifically, we examine what we call the split-door setting, where the outcome variable can be split into ... More
Modeling and Verification of a Multi-Agent Argumentation System using NuSMVSep 19 2012Autonomous intelligent agent research is a domain situated at the forefront of artificial intelligence. Interest-based negotiation (IBN) is a form of negotiation in which agents exchange information about their underlying goals, with a view to improve ... More
Averaging Gone Wrong: Using Time-Aware Analyses to Better Understand BehaviorMar 22 2016Apr 17 2016Online communities provide a fertile ground for analyzing people's behavior and improving our understanding of social processes. Because both people and communities change over time, we argue that analyses of these communities that take time into account ... More
MacWilliams type identities for some new $m$-spotty weight enumeratorsSep 17 2011Nov 11 2011Past few years have seen an extensive use of high-density RAM chips with wide I/O data (e.g., 16, 32, 64 bits) in computer memory systems. These chips are highly vulnerable to a special type of byte error, called an $m$-spotty byte error, which can be ... More
One and two-dimensional quantum models: quenches and the scaling of irreversible entropyMar 27 2015Using the scaling relation of the ground state quantum fidelity, we propose the most generic scaling relations of the irreversible work (the residual energy) of a closed quantum system at absolute zero temperature when one of the parameters of its Hamiltonian ... More
Learning to Prescribe Interventions for Tuberculosis Patients Using Digital Adherence DataFeb 05 2019May 24 2019Digital Adherence Technologies (DATs) are an increasingly popular method for verifying patient adherence to many medications. We analyze data from one city served by 99DOTS, a phone-call-based DAT deployed for Tuberculosis (TB) treatment in India where ... More
Quantifying Error in the Presence of Confounders for Causal InferenceJul 10 2019Estimating average causal effect (ACE) is useful whenever we want to know the effect of an intervention on a given outcome. In the absence of a randomized experiment, many methods such as stratification and inverse propensity weighting have been proposed ... More
Auditing Search Engines for Differential Satisfaction Across DemographicsMay 24 2017Many online services, such as search engines, social media platforms, and digital marketplaces, are advertised as being available to any user, regardless of their age, gender, or other demographic factors. However, there are growing concerns that these ... More
Learning to Prescribe Interventions for Tuberculosis Patients Using Digital Adherence DataFeb 05 2019Jun 24 2019Digital Adherence Technologies (DATs) are an increasingly popular method for verifying patient adherence to many medications. We analyze data from one city served by 99DOTS, a phone-call-based DAT deployed for Tuberculosis (TB) treatment in India where ... More
Exploring limits to prediction in complex social systemsFeb 02 2016How predictable is success in complex social systems? In spite of a recent profusion of prediction studies that exploit online social and information network data, this question remains unanswered, in part because it has not been adequately specified. ... More
Studying and Modeling the Connection between People's Preferences and Content SharingDec 03 2014People regularly share items using online social media. However, people's decisions around sharing---who shares what to whom and why---are not well understood. We present a user study involving 87 pairs of Facebook users to understand how people make ... More
Experimental realization of mixed-synchronization in counter-rotating coupled oscillatorsMay 30 2011Recently, a novel mixed-synchronization phenomenon is observed in counter-rotating nonlinear coupled oscillators. In mixed-synchronization state: some variables are synchronized in-phase, while others are out-of-phase. We have experimentally verified ... More
New Silicon Carbide (SiC) Hetero-Junction Darlington TransistorAug 18 2010Basic SiC bipolar transistors have been studied in the past for their applications where high power or high temperature operation is required. However since the current gain in SiC bipolar transistors is very low and therefore, a large base drive is required ... More
Strings in a 2-d Extremal Black HoleDec 24 2004Jan 05 2005String theory on 2-d charged black holes corresponding to (SL(2)xU(1)_L)/U(1) exact asymmetric quotient CFTs are investigated. These backgrounds can be embedded, in particular, in a two dimensional heterotic string. In the extremal case, the quotient ... More
Critical-doping universality for cuprate superconductors: Oxygen nuclear-magnetic-resonance investigation of Ca(x)La(1-x)Ba(1.75-x)La(0.25+x)Cu(3)O(y)Nov 03 2010The critical doping levels in cuprates, where the ground state changes its nature (from an antiferromagnet to a spin glass to superconductor to metal), are not universal. We investigate the origin of these critical doping variations by measuring the in-plane ... More
Common energy scale for magnetism and superconductivity in cupratesSep 05 2002Jul 16 2004Many compounds based on CuO_2 planes (cuprates) super-conduct below a critical temperature Tc. Some of them show a second phase where a spontaneous static magnetic field appears below a critical temperature Tg, which is lower then Tc. By comparing Tc ... More
Loschmidt echo with a non-equilibrium initial state: early time scaling and enhanced decoherenceMar 04 2012Apr 11 2012We study the Loschmidt echo (LE) in a central spin model in which a central spin is globally coupled to an environment (E) which is subjected to a small and sudden quench at $t=0$ so that its state at $t=0^+$, remains the same as the ground state of the ... More
Frequency Domain Approach for Activity Classification using AccelerometerJul 22 2011Activity classification was performed using MEMS accelerometer and wireless sensor node for wireless sensor network environment. Three axes MEMS accelerometer measures body's acceleration and transmits measured data with the help of sensor node to base ... More
Role of marginality in quantum fidelity and Loschmidt echo: Dirac points in 2-DJan 09 2013Apr 08 2013We investigate the effect of marginality on the ground state fidelity and Loschmidt echo. For this purpose, we study the above quantities near the quantum critical point (QCP) of the two-dimensional (2-D) Dirac Hamiltonian in the presence of a mass term ... More
Quenches and dynamical phase transitions in a non-integrable quantum Ising modelJun 01 2015We study quenching dynamics of a one-dimensional transverse Ising chain with nearest neighbor antiferromagentic interactions in the presence of a longitudinal field which renders the model non-integrable. The dynamics of the spin chain is studied following ... More
Friends, Strangers, and the Value of Ego Networks for RecommendationApr 17 2013Two main approaches to using social network information in recommendation have emerged: augmenting collaborative filtering with social data and algorithms that use only ego-centric data. We compare the two approaches using movie and music data from Facebook, ... More
Study of Loschmidt Echo for a qubit coupled to an XY-spin chain environmentMar 04 2012We study the temporal evolution of a central spin-1/2 (qubit) coupled to the environment which is chosen to be a spin-1/2 transverse XY spin chain. We explore the entire phase diagram of the spin-Hamiltonian and investigate the behavior of Loschmidt echo(LE) ... More
A Framework for Prefetching Relevant Web Pages using Predictive Prefetching Engine (PPE)Sep 28 2011This paper presents a framework for increasing the relevancy of the web pages retrieved by the search engine. The approach introduces a Predictive Prefetching Engine (PPE) which makes use of various data mining algorithms on the log maintained by the ... More
Predictability of Popularity: Gaps between Prediction and UnderstandingMar 31 2016Can we predict the future popularity of a song, movie or tweet? Recent work suggests that although it may be hard to predict an item's popularity when it is first introduced, peeking into its early adopters and properties of their social network makes ... More
Towards Practical Privacy-Preserving Analytics for IoT and Cloud Based Healthcare SystemsApr 11 2018Modern healthcare systems now rely on advanced computing methods and technologies, such as Internet of Things (IoT) devices and clouds, to collect and analyze personal health data at an unprecedented scale and depth. Patients, doctors, healthcare providers, ... More
Tuning the presence of dynamical phase transitions in a generalized $XY$ spin chainJan 19 2016Jun 07 2016We study an integrable spin chain with three spin interactions and the staggered field ($\lambda$) while the latter is quenched either slowly (in a linear fashion in time ($t$) as $t/\tau$ where $t$ goes from a large negative value to a large positive ... More
Quench Dynamics of Edge States in 2-D Topological Insulator RibbonsApr 08 2013We study the dynamics of edge states of the two dimensional BHZ Hamiltonian in a ribbon geometry following a sudden quench to the quantum critical point separating the topological insulator phase from the trivial insulator phase. The effective edge state ... More
Dual conformal transformations of smooth holographic Wilson loopsOct 23 2016We study dual conformal transformations of minimal area surfaces in $AdS_5 \times S^5$ corresponding to holographic smooth Wilson loops and some other related observables. To act with dual conformal transformations we map the string solutions to the dual ... More
Non-commutative holography and scattering amplitudes in a large magnetic backgroundJan 28 2009Feb 06 2009We study planar gluon scattering amplitudes and Wilson loops in non-commutative gauge theory. Our main results are: 1. We find the map between observables in non-commutative gauge theory and their holographic dual. In that map, the region near the boundary ... More
Products of Brauer Severi surfacesJun 23 2007Let $\{P_i\}_{1 \leq i \leq r}$ and $\{Q_i\}_{1 \leq i \leq r}$ be two collections of Brauer Severi surfaces (resp. conics) over a field $k$. We show that the subgroup generated by the $P_i's$ in $Br(k)$ is the same as the subgroup generated by the $Q_i's$ ... More
Algebraic Curves for Factorized String SolutionsFeb 04 2013We show how to construct an algebraic curve for factorized string solution in the context of the AdS/CFT correspondence. We define factorized solutions to be solutions where the flat-connection becomes independent of one of the worldsheet variables by ... More
Stress of a spatially uniform dislocation density fieldSep 06 2018It can be shown that the stress produced by a spatially uniform dislocation density field in a body comprising a linear elastic material under no loads vanishes. We prove that the same result does not hold in general in the geometrically nonlinear case. ... More
On Weingarten-Volterra defectsSep 06 2018The kinematic theory of Weingarten-Volterra line defects is revisited, both at small and finite deformations. Existing results are clarified and corrected as needed, and new results are obtained. The primary focus is to understand the relationship between ... More
Comments on $T\bar T$, $J\bar{T}$ and String TheoryMar 16 2019These notes contain some aspects of the holographic duality between the perturbative superstring on current-current deformations of $AdS_3\times S^1\times{\cal N}$ and single-trace $T\bar T$ and $J\bar T$ deformed $CFT_2$.
Quasi-abelian hearts of twin cotorsion pairs on triangulated categoriesJul 14 2018Jun 23 2019We prove that, under a mild assumption, the heart H of a twin cotorsion pair ((S,T),(U,V)) on a triangulated category C is a quasi-abelian category. If C is also Krull-Schmidt and T=U, we show that the heart of the cotorsion pair (S,T) is equivalent to ... More
The Resultant of an Unmixed Bivariate SystemSep 11 2002This paper gives an explicit method for computing the resultant of any sparse unmixed bivariate system with given support. We construct square matrices whose determinant is exactly the resultant. The matrices constructed are of hybrid Sylvester and B\'ezout ... More
On String Field Theory and Effective ActionsJun 04 1992A truncation of string field theory is compared with the duality invariant effective action of $D=4, N=4$ heterotic strings to cubic order. The three string vertex must satisfy a set of compatibility conditions. Any cyclic three string vertex is compatible ... More
The Brauer Group of a Smooth OrbifoldNov 05 2008Let $k$ be a field and $X/k$ be a smooth quasiprojective orbifold. Let $X\to \underline{X}$ be its coarse moduli space. In this paper we study the Brauer group of $X$ and compare it with the Brauer group of the smooth locus of $\underline{X}$.
Mathematics for cryo-electron microscopyMar 12 2018Single-particle cryo-electron microscopy (cryo-EM) has recently joined X-ray crystallography and NMR spectroscopy as a high-resolution structural method for biological macromolecules. Cryo-EM was selected by Nature Methods as Method of the Year 2015, ... More
On the Grothendieck ring of varietiesNov 07 2013Nov 11 2013Let $\operatorname{K}_0(\operatorname{Var}_k)$ denote the Grothendieck ring of $k$-varieties over an algebraically closed field $k$. Larsen and Lunts asked if two $k$-varieties having the same class in $\operatorname{K}_0 (\operatorname{Var}_k)$ are piecewise ... More
Semicontinuity of Persistence DiagramsJan 13 2016May 27 2016We generalize the persistence diagram of Cohen-Steiner, Edelsbrunner, and Harer to the setting of constructible persistence modules valued in any symmetric monoidal category. This persistence diagram is stable to small perturbations of the module. If ... More
Auslander-Reiten theory in quasi-abelian and Krull-Schmidt categoriesSep 28 2018Jun 10 2019We generalise some of the theory developed for abelian categories in papers of Auslander and Reiten to semi-abelian and quasi-abelian categories. In addition, we generalise some Auslander-Reiten theory results of S. Liu for Krull-Schmidt categories by ... More
Rank 3 arithmetically Cohen-Macaulay bundles on hypersurfacesJun 10 2015Let $X$ be a smooth projective hypersurface of dimension $\geq 5$ and let $E$ be an arithmetically Cohen-Macaulay bundle on $X$ of any rank. We prove that $E$ splits as a direct sum of line bundles if and only if $H^i_*(X, \wedge^2 E) = 0$ for $i = 1,2,3,4$. ... More
A Few Ways to Destroy Entropic Chaoticity on Kac's SphereAug 31 2012In this work we discuss a few ways to create chaotic families that are not entropically chaotic on Kac's Sphere. We present two types of examples: limiting convex combination of an entropically chaotic family with a particularly 'bad' non-entropic family, ... More
Hecke-Bochner identity and eigenfunctions associated to Gelfand pairs on the Heisenberg groupJun 12 2012Let $\mathbb{H}^{n}$ be the $(2n+1)$-dimensional Heisenberg group, and let $K$ be a compact subgroup of U(n), such that $(K,\mathbb{H}^{n})$ is a Gelfand pair. Also assume that the $K$-action on $\mathbb{C}^n$ is polar. We prove a Hecke-Bochner identity ... More
Duality as a Gauge Symmetry and Topology ChangeOct 04 1993Duality groups as (spontaneously broken) gauge symmetries for toroidal backgrounds, and their role in ($\infty$-dimensional) underlying string gauge algebras are reviewed. For curved backgrounds, it is shown that there is a duality in the moduli space ... More
Complexity Theoretic Limitations on Learning HalfspacesMay 21 2015Mar 13 2016We study the problem of agnostically learning halfspaces which is defined by a fixed but unknown distribution $\mathcal{D}$ on $\mathbb{Q}^n\times \{\pm 1\}$. We define $\mathrm{Err}_{\mathrm{HALF}}(\mathcal{D})$ as the least error of a halfspace classifier ... More
Wilson Loops and Minimal Surfaces Beyond the Wavy ApproximationJan 17 2015We study Euclidean Wilson loops at strong coupling using the AdS/CFT correspondence, where the problem is mapped to finding the area of minimal surfaces in Hyperbolic space. We use a formalism introduced recently by Kruczenski to perturbatively compute ... More
A PTAS for Agnostically Learning HalfspacesOct 26 2014Jun 25 2015We present a PTAS for agnostically learning halfspaces w.r.t. the uniform distribution on the $d$ dimensional sphere. Namely, we show that for every $\mu>0$ there is an algorithm that runs in time $\mathrm{poly}(d,\frac{1}{\epsilon})$, and is guaranteed ... More
Vandalism Detection in Wikipedia: a Bag-of-Words Classifier ApproachJan 05 2010A bag-of-words based probabilistic classifier is trained using regularized logistic regression to detect vandalism in the English Wikipedia. Isotonic regression is used to calibrate the class membership probabilities. Learning curve, reliability, ROC, ... More
Dual conformal transformations of smooth holographic Wilson loopsOct 23 2016Nov 11 2016We study dual conformal transformations of minimal area surfaces in $AdS_5 \times S^5$ corresponding to holographic smooth Wilson loops and some other related observables. To act with dual conformal transformations we map the string solutions to the dual ... More
On a Method for Multiscale Solid MechanicsMay 20 2002Given a fine-scale physical theory characterized by an evolutionary system of equations and a set of quantities, defined from the variables of the fine theory, that serve as a coarse representation of the fine scale phenomena, a systematic method for ... More
Splitting of low rank ACM bundles on hypersurfaces of high dimensionApr 08 2013Feb 02 2015Let $X$ be a smooth projective hypersurface. In this note we show that any rank 3 arithmetically Cohen-Macaulay vector bundle over $X$ splits when dim $X \geq 7$. We also find a splitting criterion for rank 4 arithmetically Cohen-Macaulay vector bundles ... More
Driving Forces and Boundary Conditions in Continuum Dislocation MechanicsMay 20 2002As a guide to constitutive specification, driving forces for dislocation velocity and nucleation rates are derived for a field theory of dislocation mechanics. A condition of closure for the theory in the form of a boundary condition for dislocation density ... More
On Non-Perturbative Results in Supersymmetric Gauge Theories - A LectureNov 20 1996Some notions in non-perturbative dynamics of supersymmetric gauge theories are being reviewed. This is done by touring through a few examples.
QED_2 in Curved BackgroundsApr 10 1996Apr 12 1996Here we discuss the two dimensional quantum electrodynamics in curved space-time, especially in the background of some black holes. We first show the existence of some new quantum mechanical solution which has interesting properties. Then for some special ... More
A Counter Example to Cercignani's Conjecture for the $d$ Dimensional Kac ModelApr 26 2012Kac's $d$ dimensional model gives a linear, many particle, binary collision model from which, under suitable conditions, the celebrated Boltzmann equation, in its spatially homogeneous form, arise as a mean field limit. The ergodicity of the evolution ... More
On the Subadditivity of the Entropy on the SphereApr 05 2014Apr 01 2015We present a refinement of a known entropic inequality on the sphere, finding suitable conditions under which the uniform probability measure on the sphere behaves asymptomatically like the Gaussian measure on $\mathbb{R}^N$ with respect to the entropy. ... More
Grothendieck Rings of Theories of ModulesFeb 18 2013The model-theoretic Grothendieck ring of a first order structure, as defined by Krajic\v{e}k and Scanlon, captures some combinatorial properties of the definable subsets of finite powers of the structure. In this paper we compute the Grothendieck ring, ... More
Split-door criterion for causal identification: Automatic search for natural experimentsNov 28 2016Unobserved or unknown confounders complicate even the simplest attempts to estimate the effect of one variable on another using observational data. When cause and effect are both affected by unobserved confounders, methods based on identifying natural ... More
Automated Classification of Hand-grip action on Objects using Machine LearningMar 09 2018Brain computer interface is the current area of research to provide assistance to disabled persons. To cope up with the growing needs of BCI applications, this paper presents an automated classification scheme for handgrip actions on objects by using ... More
Asymptotic work statistics of periodically driven Ising chainsMay 12 2015Nov 19 2015We study the work statistics of a periodically-driven integrable closed quantum system, addressing in particular the role played by the presence of a quantum critical point. Taking the example of a one-dimensional transverse Ising model in the presence ... More
Fabrication of Hollow AlAu2 Nanoparticles by Solid State Dewetting and Oxidation of Al on Sapphire SubstrateJul 06 2018Jul 09 2018The Al-Au binary diffusion couple is a classic example of the system exhibiting Kirkendall voiding during interdiffusion. We demonstrate that this effect, which is a major reason for failures of the wire bonds in microelectronics, can be utilized for ... More
Estimating the Causal Impact of Recommendation Systems from Observational DataOct 19 2015Recommendation systems are an increasingly prominent part of the web, accounting for up to a third of all traffic on several of the world's most popular sites. Nevertheless, little is known about how much activity such systems actually cause over and ... More
Algorithms for Generating Ordered Solutions for Explicit AND/OR StructuresJan 23 2014We present algorithms for generating alternative solutions for explicit acyclic AND/OR structures in non-decreasing order of cost. The proposed algorithms use a best first search technique and report the solutions using an implicit representation ordered ... More
Slow quenches in a quantum Ising chain; dynamical phase transitions and topologyJan 07 2016Jun 07 2016We study the slow quenching dynamics (characterized by an inverse rate, $\tau^{-1}$) of a one-dimensional transverse Ising chain with nearest neighbor ferromagentic interactions across the quantum critical point (QCP) and analyze the Loschmidt overlap ... More
Loschmidt echo and dynamical fidelity in periodically driven quantum systemsFeb 04 2014Jun 23 2014We study the dynamical fidelity $\mathcal{F} (t)$ and the Loschmidt echo $\mathcal{L} (t)$, following a periodic driving of the transverse magnetic field of a quantum Ising chain (back and forth across the quantum critical point) by calculating the overlap ... More
Cryo-EM reconstruction of continuous heterogeneity by Laplacian spectral volumesJul 01 2019Single-particle electron cryomicroscopy is an essential tool for high-resolution 3D reconstruction of proteins and other biological macromolecules. An important challenge in cryo-EM is the reconstruction of non-rigid molecules with parts that move and ... More
Beyond the Singularity of the 2-D Charged Black HoleMay 16 2003Jul 23 2003Two dimensional charged black holes in string theory can be obtained as exact (SL(2,R)xU(1))/U(1) quotient CFTs. The geometry of the quotient is induced from that of the group, and in particular includes regions beyond the black hole singularities. Moreover, ... More
Strings in Singular Time-Dependent BackgroundsMay 16 2003We review the construction of time-dependent backgrounds with space-like singularities. We mainly consider exact CFT backgrounds. The algebraic and geometric aspects of these backgrounds are discussed. Physical issues, results and difficulties associated ... More
The Non-local Kardar-Parisi-Zhang Equation With Spatially Correlated NoiseFeb 13 1999The effects of spatially correlated noise on a phenomenological equation equivalent to a non-local version of the Kardar-Parisi-Zhang equation are studied via the dynamic renormalization group (DRG) techniques. The correlated noise coupled with the long ... More
Growing random networks under constraintsJul 18 2001Jul 21 2001We study the evolution of a random graph under the constraint that the diameter remain constant as the graph grows. We show that if the graph maintains the form of its link distribution it must be scale-free with exponent between 2 and 3. These uniqueness ... More
Local Correction of JuntasSep 16 2011Dec 24 2011A Boolean function f over n variables is said to be q-locally correctable if, given a black-box access to a function g which is "close" to an isomorphism f_sigma of f, we can compute f_sigma(x) for any x in Z_2^n with good probability using q queries ... More
The effect of the SOS response on the mean fitness of unicellular populations: A quasispecies approachApr 01 2008This paper develops a quasispecies model that incorporates the SOS response. We consider a unicellular, asexually replicating population of organisms, whose genomes consist of a single, double-stranded DNA molecule, i.e. one chromosome. We assume that ... More
The Statistics of the Points Where Nodal Lines Intersect a Reference CurveApr 25 2007Jun 27 2007We study the intersection points of a fixed planar curve $\Gamma$ with the nodal set of a translationally invariant and isotropic Gaussian random field $\Psi(\bi{r})$ and the zeros of its normal derivative across the curve. The intersection points form ... More
The price of bandit information in multiclass online classificationFeb 05 2013Jul 09 2013We consider two scenarios of multiclass online learning of a hypothesis class $H\subseteq Y^X$. In the {\em full information} scenario, the learner is exposed to instances together with their labels. In the {\em bandit} scenario, the true label is not ... More
Stable and Metastable Vacua in SQCDOct 03 2007Oct 10 2007We study deformations of N=1 supersymmetric QCD that exhibit a rich landscape of supersymmetric and non-supersymmetric vacua.
Effective Actions and Gauge Field StabilityAug 09 1995By studying an effective action description of the coupling of charged gauge fields in N=2 SU(n) supersymmetric Yang-Mills theories, we can describe regions of moduli space where one or more of these fields becomes unphysical. We discuss subtleties in ... More
Introduction to DualityJun 27 1994We describe the duality between different geometries which arises by considering the classical and quantum harmonic map problem. To appear in ``Essays on Mirror Manifolds II''.
String Theory Versus Black Hole ComplementarityAug 20 2012It is argued that string theory on the Euclidean version of the Schwarzschild black hole -- the cigar geometry -- admits a zero mode that is localized at the tip of the cigar. The presence of this mode implies that in string theory, unlike in general ... More
Superpartner spectrum of minimal gaugino-gauge mediationNov 07 2010Dec 27 2010We evaluate the sparticle mass spectrum in the minimal four-dimensional construction that interpolates between gaugino and ordinary gauge mediation at the weak scale. We find that even in the hybrid case -- when the messenger scale is comparable to the ... More
Fundamental Strings and Black HolesNov 06 2006Jan 07 2007We propose a black hole thermodynamic description of highly excited charged and uncharged perturbative string states in 3+1 dimensional type II and 4+1 dimensional heterotic string theory. We also discuss the generalization to extremal and non-extremal ... More
On the BRST Operator Structure of the N=2 StringFeb 12 1993The BRST operator cohomology of $N=2$ $2d$ supergravity coupled to matter is presented. Descent equations for primary superfields of the matter sector are derived. We find one copy of the cohomology at ghost number one, two independent copies at ghost ... More
Stress-structure relation in dense colloidal melt under forward and instantaneous reversal of shearOct 29 2014Jun 16 2015Dense supercooled colloidal melt in forward shear from a quiescent state shows overshoot in shear stress at 10% strain with an unchanged fluid structure at equal stress before and after overshoot. In addition, we find overshoot in normal stress with a ... More
Rescaling and other forms of unsupervised preprocessing introduce bias into cross-validationJan 25 2019Cross-validation of predictive models is the de-facto standard for model selection and evaluation. In proper use, it provides an unbiased estimate of a model's predictive performance. However, data sets often undergo a preliminary data-dependent transformation, ... More
Heat capacity evidence for conventional superconductivity in the Type-II Dirac semi-metal PdTe$_2$Jan 10 2018We use electrical transport, magnetoresistance, and heat capacity measurements on high quality single crystals of the recently discovered superconducting Type-II Dirac semi-metal PdTe$_2$, to probe the nature of it's superconducting phase. The magnitude ... More
Learning without Interaction Requires SeparationSep 24 2018Feb 07 2019One of the key resources in large-scale learning systems is the number of rounds of communication between the server and the clients holding the data points. We study this resource for systems with two types of constraints on the communication from each ... More
The effect of long range interactions on the stability of classical and quantum solidsJan 01 2008We generalise the celebrated Peierls' argument to study the stability of a long-range interacting classical solid. Long-range interaction implies that all the atomic oscillators are coupled to each other via a harmonic potential, though the coupling strength ... More
Multiparameter Persistent HomologyMay 30 2019Persistent homology studies the birth and death of cycles in a parameterized family of spaces. In this paper, we study the birth and death of cycles in a multifiltration of a chain complex. The result is a multiparameter persistence diagram that is stable ... More
Dislocation pattern formation in finite deformation crystal plasticityDec 01 2018Stressed dislocation pattern formation in crystal plasticity at finite deformation is demonstrated for the first time. Size effects are also demonstrated within the same mathematical model. The model involves two extra material parameters beyond the requirements ... More