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Results for "Kartik Nagar"

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Automated Parameterized Verification of CRDTsMay 14 2019Maintaining multiple replicas of data is crucial to achieving scalability, availability and low latency in distributed applications. Conflict-free Replicated Data Types (CRDTs) are important building blocks in this domain because they are designed to ... More
Gravitational recoil in nonspinning black hole binaries: the span of test-mass resultsJun 26 2013Dec 16 2013We consider binary systems of coalescing, nonspinning, black holes of masses $m_{1}$ and $m_{2}$ and show that the gravitational recoil velocity for any mass ratio can be obtained accurately by extrapolating the waveform of the test-mass limit case. The ... More
Post-merger analytic templates for GW150914Jun 13 2016Following the new analytic description of the postmerger (ringdown) waveform of coalescing, nonprecessing, spinning, black hole binaries (BBHs) introduced in Phys.~Rev.~D~90, 024054 (2014), we propose an analytic, closed form, time-domain, representation ... More
Effective one body Hamiltonian of two spinning black-holes with next-to-next-to-leading order spin-orbit couplingJun 21 2011Sep 05 2013Building on the recently computed next-to-next-to-leading order (NNLO) post-Newtonian (PN) spin-orbit Hamiltonian for spinning binaries \cite{Hartung:2011te} we extend the effective-one-body (EOB) description of the dynamics of two spinning black-holes ... More
Condensation transition in a model with attractive particles and non-local hopsOct 12 2009We study a one dimensional nonequilibrium lattice model with competing features of particle attraction and non-local hops. The system is similar to a zero range process (ZRP) with attractive particles but the particles can make both local and non-local ... More
Rendezvous with SensitivityJan 19 2019Let $(X,d)$ be a compact metric space and $f:X \to X$ be a self-map. The compact dynamical system $(X,f)$ is called sensitive or sensitivity depends on initial conditions, if there is a positive constant $\delta$ such that in each non-empty open subset ... More
Molecular Gas Properties in the Central Kiloparsec of Barred and Unbarred SpiralsAug 01 2001We study the molecular gas properties in the central kiloparsec of 29 barred and 15 unbarred spirals from the BIMA Survey of Nearby Galaxies (SONG). We find that the mean nuclear molecular gas surface density of barred spirals (<Sigma_{nuc}>=309 +/- 71 ... More
The First Law of Black Hole Mechanics for Fields with Internal Gauge FreedomNov 02 2015Jun 16 2016We derive the first law of black hole mechanics for physical theories based on a local, covariant and gauge-invariant Lagrangian where the dynamical fields transform non-trivially under the action of internal gauge transformations. The theories of interest ... More
Estimating Kullback-Leibler Divergence Using Kernel MachinesMay 02 2019Recently, a method called the Mutual Information Neural Estimator (MINE) that uses neural networks has been proposed to estimate mutual information and more generally the Kullback-Leibler (KL) divergence between two distributions. The method uses the ... More
Fixation of mutators in asexual populations: the role of genetic drift and epistasisMay 28 2012Oct 24 2012We study the evolutionary dynamics of an asexual population of nonmutators and mutators on a class of epistatic fitness landscapes. We consider the situation in which all mutations are deleterious and mutators are produced from nonmutators continually ... More
Exact phase diagram of quasispecies model with mutation rate modifierAug 05 2008Jan 23 2009We consider an infinite asexual population with a mutator allele which can elevate mutation rates. With probability $f$, a transition from nonmutator to mutator state occurs but the reverse transition is forbidden. We find that at $f=0$, the population ... More
An improved analytical description of inspiralling and coalescing black-hole binariesFeb 02 2009Mar 19 2009We present an analytical formalism, within the Effective-One-Body framework, which predicts gravitational-wave signals from inspiralling and coalescing black-hole binaries that agree, within numerical errors, with the results of the currently most accurate ... More
Binary black hole merger waveforms in the extreme mass ratio limitDec 23 2006Feb 09 2007We discuss the transition from quasi-circular inspiral to plunge of a system of two nonrotating black holes of masses $m_1$ and $m_2$ in the extreme mass ratio limit $m_1m_2\ll (m_1+m_2)^2$. In this limit, we compare the merger waveforms obtained by two ... More
Residence Time Distribution of Sand Grains in the 1-Dimensional Abelian Sandpile ModelMar 31 2004We study the probability distribution of residence time, $T$, of the sand grains in the one dimensional abelian sandpile model on a lattice of $L$ sites, for $T<<L^2$ and $T>>L^2$. The distribution function decays as $\exp(-\frac{K_LT}{L^2})$. We numerically ... More
The Effective One Body description of the Two-Body problemJun 09 2009The Effective One Body (EOB) formalism is an analytical approach which aims at providing an accurate description of the motion and radiation of coalescing binary black holes with arbitrary mass ratio. We review the basic elements of this formalism and ... More
A new analytic representation of the ringdown waveform of coalescing spinning black hole binariesJun 02 2014Jul 10 2014We propose a new way of analyzing, and analytically representing, the ringdown part of the gravitational wave signal emitted by coalescing black hole binaries.By contrast with the usual {\it linear} decomposition of the multipolar complex waveform $h(t)$ ... More
Effective One Body description of tidal effects in inspiralling compact binariesNov 27 2009The late part of the gravitational wave signal of binary neutron star inspirals can in principle yield crucial information on the nuclear equation of state via its dependence on relativistic tidal parameters. In the hope of analytically describing the ... More
Passive Sliders and Scaling: from Cusps to DivergencesAug 20 2008The steady state reached by a system of particles sliding down a fluctuating surface has interesting properties. Particle clusters form and break rapidly, leading to a broad distribution of sizes and large fluctuations. The density-density correlation ... More
Comparing Effective-One-Body gravitational waveforms to accurate numerical dataNov 16 2007Dec 19 2007We continue the program of constructing, within the Effective-One-Body (EOB) approach, high accuracy, faithful analytic waveforms describing the gravitational wave signal emitted by inspiralling and coalescing binary black holes (BHs). We present the ... More
Final spin of a coalescing black-hole binary: an Effective-One-Body approachApr 26 2007Jul 26 2007We update the analytical estimate of the final spin of a coalescing black-hole binary derived within the Effective-One-Body (EOB) approach. We consider unequal-mass non-spinning black-hole binaries. It is found that a more complete account of relevant ... More
Factorisation of soft gluons in multiparton scatteringDec 22 2018We show that soft gluons exchanged between the two colliding protons in multiparton scattering processes can be decoupled, such that their effects are described by the vacuum expectation values of Wilson lines. Our argument relies on nonabelian Ward identities ... More
Absence of jamming in ant trails: Feedback control of self propulsion and noiseOct 16 2014We present a model of ant traffic considering individual ants as self-propelled particles undergoing single file motion on a one-dimensional trail. Recent experiments on unidirectional ant traffic in well-formed natural trails showed that the collective ... More
Resetting of fluctuating interfaces at power-law timesApr 22 2016What happens when the time evolution of a fluctuating interface is interrupted with resetting to a given initial configuration after random time intervals $\tau$ distributed as a power-law $\sim \tau^{-(1+\alpha)};~\alpha > 0$? For an interface of length ... More
Binary black hole merger in the extreme-mass-ratio limit: a multipolar analysisMar 02 2010Dec 14 2010Building up on previous work, we present a new calculation of the gravitational wave (GW) emission generated during the transition from quasi-circular inspiral to plunge, merger and ringdown by a binary system of nonspinning black holes, of masses $m_1$ ... More
Gravitational waves from pulsations of neutron stars described by realistic Equations of StateMar 26 2008Aug 29 2008In this work we discuss the time-evolution of nonspherical perturbations of a nonrotating neutron star described by a realistic Equation of State (EOS). We analyze 10 different EOS for a large sample of neutron star models. Various kind of generic initial ... More
A new effective-one-body description of coalescing nonprecessing spinning black-hole binariesJun 26 2014We present a new, tunable effective-one-body (EOB) model of the motion and radiation of coalescing black hole binaries with arbitrary mass ratio and aligned spins. The most novel feature of our formalism is the introduction, and systematic use, of the ... More
Relativistic tidal properties of neutron starsMay 30 2009Dec 03 2009We study the various linear responses of neutron stars to external relativistic tidal fields. We focus on three different tidal responses, associated to three different tidal coefficients: (i) a gravito-electric-type coefficient G\mu_\ell=[length]^{2\ell+1} ... More
Faithful Effective-One-Body waveforms of small-mass-ratio coalescing black-hole binariesMay 17 2007Jul 26 2007We address the problem of constructing high-accuracy, faithful analytic waveforms describing the gravitational wave signal emitted by inspiralling and coalescing binary black holes. We work within the Effective-One-Body (EOB) framework and propose a methodology ... More
Fluid accretion onto relativistic stars and gravitational radiationAug 15 2004This article reports results from numerical simulations of the gravitational radiation emitted from nonrotating relativistic stars as a result of the axisymmetric accretion of layers of perfect fluid matter, shaped in the form of quadrupolar shells. We ... More
Gauge-invariant Non-spherical Metric Perturbations of Schwarzschild Black-Hole SpacetimesFeb 14 2005Apr 02 2006The theory of gauge-invariant non-spherical metric perturbations of Schwarzschild black hole spacetimes is now well established. Yet, as different notations and conventions have been used throughout the years, the literature on the subject is often confusing ... More
Dynamics of the Induced Shift MapFeb 09 2017Feb 13 2017In this article, we compare the dynamics of the shift map and its induced counterpart on the hyperspace of the shift space. We show that many of the properties of induced shift map can be easily demonstrated by appropriate sequences of symbols. We compare ... More
Eigenvalue monotonicity of $q$-Laplacians of trees along a posetNov 27 2017Feb 26 2018Let $T$ be a tree on $n$ vertices with $q$-Laplacian $L_{T}^{q}$. Let $GTS_n$ be the generalized tree shift poset on the set of unlabelled trees with $n$ vertices. We prove that for all $q \in R$, going up on $GTS_n$ has the following effect: the spectral ... More
iResum: a new paradigm for resumming gravitational wave amplitudesJun 01 2016Sep 28 2016We introduce a new, resummed, analytical form of the post-Newtonian (PN), factorized, multipolar amplitude corrections $f_{\ell m}$ of the effective-one-body (EOB) gravitational waveform of spinning, nonprecessing, circularized, coalescing black hole ... More
Laplacian Immanantal polynomials and the GTS poset on TreesOct 06 2017Feb 27 2018Let $T$ be a tree on $n$ vertices with Laplacian $L_T$ and let $GTS_n$ be the generalized tree shift poset on the set of unlabelled trees on $n$ vertices. Inequalities are known for coefficients of the characteristic polynomial of $L_T$ as we go up the ... More
Ultra-High Energy Cosmic Rays Detected by the Pierre Auger Observatory: First Direct Evidence, and its Implications, that a Subset Originate in Nearby RadiogalaxiesJun 19 2008(abridged) The Pierre Auger Collaboration has reported 27 Ultra-High Energy Cosmic Ray Events (UHECRs) with energies above 56 EeV and well determined arrival directions as of 2007 August 31. They find that the arrival directions are not isotropic, but ... More
Linear and nonlinear optical spectroscopy of a strongly-coupled microdisk-quantum dot systemJul 23 2007Jul 27 2007A fiber taper waveguide is used to perform direct optical spectroscopy of a microdisk-quantum-dot system, exciting the system through the photonic (light) channel rather than the excitonic (matter) channel. Strong coupling, the regime of coherent quantum ... More
Optical fiber taper coupling and high-resolution wavelength tuning of microdisk resonators at cryogenic temperaturesNov 14 2006A system for studying microcavity resonators at cryogenic temperatures (~10 K) through evanescent coupling via optical fiber taper waveguides is reported, and efficient fiber coupling to AlGaAs microdisk cavities with embedded quantum dots is demonstrated. ... More
Mode Coupling and Cavity-Quantum-Dot Interactions in a Fiber-Coupled Microdisk CavityJun 17 2006Jan 26 2007A quantum master equation model for the interaction between a two-level system and whispering-gallery modes (WGMs) of a microdisk cavity is presented, with specific attention paid to current experiments involving a semiconductor quantum dot (QD) embedded ... More
Stability and dynamical properties of material flow systems on random networksFeb 12 2009The theory of complex networks and of disordered systems is used to study the stability and dynamical properties of a simple model of material flow networks defined on random graphs. In particular we address instabilities that are characteristic of flow ... More
Design of two-dimensional photonic crystal defect states for quantum cascade laser resonatorsOct 11 2004Current quantum cascade lasers based upon conduction band electron transitions are predominantly TM (electrical field normal to the epitaxial direction) polarized. Here we present a study of localized defect modes, with the requisite TM polarization, ... More
Automorphic cohomology, motivic cohomology, and the adjoint $L$-functionSep 20 2016Jan 12 2017We propose a relationship between the cohomology of arithmetic groups, and the motivic cohomology of certain (Langlands-)attached motives. The motivic cohomology group in question is that related, by Beilinson's conjecture, to the adjoint $L$-function ... More
Heterojunction Vertical Band-to-Band Tunneling Transistors for Steep Subthreshold Swing and High ON CurrentMar 15 2011We propose a Heterojunction Vertical Tunneling FET and show using self-consistent ballistic quantum transport simulations that it can provide very steep subthreshold swings and high ON current, thereby improving the scalability of Tunnel FETs for high ... More
Hybrid gap modes induced by fiber taper waveguides: application in spectroscopy of single solid-state emitters deposited on thin filmsFeb 19 2010We show, via simulations, that an optical fiber taper waveguide can be an efficient tool for photoluminescence and resonant, extinction spectroscopy of single emitters, such as molecules or colloidal quantum dots, deposited on the surface of a thin dielectric ... More
Entropy measures for complex networks: Toward an information theory of complex topologiesJul 09 2009Oct 16 2009The quantification of the complexity of networks is, today, a fundamental problem in the physics of complex systems. A possible roadmap to solve the problem is via extending key concepts of information theory to networks. In this paper we propose how ... More
Herding the Crowd: Automated Planning for Crowdsourced PlanningJul 29 2013There has been significant interest in crowdsourcing and human computation. One subclass of human computation applications are those directed at tasks that involve planning (e.g. travel planning) and scheduling (e.g. conference scheduling). Much of this ... More
Robustness of the Drosophila segment polarity network to transient perturbationsJun 18 2009Continuous and Boolean models for the Drosophila segment polarity network have shown that the system is able to maintain the wild-type pattern when subjected to sustained changes in the interaction parameters and initial conditions. Embryo development ... More
Energetics of a rotating charged black hole in 5-dimensional supergravityFeb 18 2009Jan 08 2010We investigate the properties of the event horizon and static limit for a charged rotating black hole solution of minimal supergravity theory in (1 + 4) dimension. Unlike the four-dimensional case, there are in general two rotations, and they couple to ... More
Guiding CTC Posterior Spike Timings for Improved Posterior Fusion and Knowledge DistillationApr 17 2019Conventional automatic speech recognition (ASR) systems trained from frame-level alignments can easily leverage posterior fusion to improve ASR accuracy and build a better single model with knowledge distillation. End-to-end ASR systems trained using ... More
Gibbs entropy of networks ensembles by cavity methodsJan 26 2010May 25 2010The Gibbs entropy of a microcanonical network ensemble is the logarithm of the number of network configurations compatible with a set of hard constraints. This quantity characterizes the level of order and randomness encoded in features of a given real ... More
Bonsai: Synthesis-Based Reasoning for Type SystemsAug 01 2017We describe algorithms for symbolic reasoning about executable models of type systems, supporting three queries intended for designers of type systems. First, we check for type soundness bugs and synthesize a counterexample program if such a bug is found. ... More
Efficient spectroscopy of single embedded emitters using optical fiber taper waveguidesApr 17 2009Jun 11 2009A technique based on using optical fiber taper waveguides for probing single emitters embedded in thin dielectric membranes is assessed through numerical simulations. For an appropriate membrane geometry, photoluminescence collection efficiencies in excess ... More
Automorphic cohomology, motivic cohomology, and the adjoint $L$-functionSep 20 2016We propose a relationship between the cohomology of arithmetic groups, and the motivic cohomology of certain (Langlands-)attached motives. The motivic cohomology group in question is that related, by Beilinson's conjecture, to the adjoint $L$-function ... More
Phase Transitions in Operational RiskSep 14 2006Dec 06 2006In this paper we explore the functional correlation approach to operational risk. We consider networks with heterogeneous a-priori conditional and unconditional failure probability. In the limit of sparse connectivity, self-consistent expressions for ... More
Periods of quaternionic Shimura varieties. IOct 01 2016We study "quadratic periods" on quaternionic Shimura varieties and formulate an integral refinement of Shimura's conjecture regarding Petersson inner products of automorphic forms that are related by the Jacquet-Langlands correspondence. The main result ... More
Fiber-coupled semiconductor waveguides as an efficient optical interface to a single quantum dipoleMay 18 2009Sep 17 2009We theoretically investigate the interaction of a single quantum dipole with the modes of a fiber-coupled semiconductor waveguide. Through a combination of tight modal confinement and phase-matched evanescent coupling, we predict that approximately 70 ... More
Strong clustering of non-interacting, passive sliders driven by a Kardar-Parisi-Zhang surfaceOct 14 2005We study the clustering of passive, non-interacting particles moving under the influence of a fluctuating field and random noise, in one dimension. The fluctuating field in our case is provided by a surface governed by the Kardar-Parisi-Zhang (KPZ) equation ... More
Passive Sliders on Fluctuating Surfaces: Strong-Clustering StatesMay 11 2005We study the clustering properties of particles sliding downwards on a fluctuating surface evolving through the Kardar-Parisi-Zhang equation, a problem equivalent to passive scalars driven by a Burgers fluid. Monte Carlo simulations on a discrete version ... More
Improved resummation of post-Newtonian multipolar waveforms from circularized compact binariesNov 13 2008Mar 11 2009We improve and generalize a resummation method of post-Newtonian multipolar waveforms from circular compact binaries introduced in Refs. \cite{Damour:2007xr,Damour:2007yf}. One of the characteristic features of this resummation method is to replace the ... More
Gravitational Waves from Nonlinear Couplings of Radial and Polar Nonradial Modes in Relativistic StarsFeb 17 2007The post-bounce oscillations of newly-born relativistic stars are expected to lead to gravitational-wave emission through the excitation of nonradial oscillation modes. At the same time, the star is oscillating in its radial modes, with a central density ... More
Improved effective-one-body description of coalescing nonspinning black-hole binaries and its numerical-relativity completionDec 18 2012Apr 15 2013We improve the effective-one-body (EOB) description of nonspinning coalescing black hole binaries by incorporating several recent analytical advances, notably: (i) logarithmic contributions to the conservative dynamics; (ii) resummed horizon-absorption ... More
Binary black hole coalescence in the extreme-mass-ratio limit: testing and improving the effective-one-body multipolar waveformDec 11 2010Mar 10 2011We discuss the properties of the effective-one-body (EOB) multipolar gravitational waveform emitted by nonspinning black-hole binaries of masses $\mu$ and $M$ in the extreme-mass-ratio limit, $\mu/M=\nu\ll 1$. We focus on the transition from quasicircular ... More
Black Hole Instabilities and Exponential GrowthJan 12 2015Aug 26 2015Recently, a general analysis has been given of the stability with respect to axisymmetric perturbations of stationary-axisymmetric black holes and black branes in vacuum general relativity in arbitrary dimensions. It was shown that positivity of canonical ... More
Lexical State AnalyzerAug 14 2013Lexical states provide a powerful mechanism to scan regular expressions in a context sensitive manner. At the same time, lexical states also make it hard to reason about the correctness of the grammar. We first categorize the related correctness issues ... More
Sub-nanosecond Electro-optic Modulation of Triggered Single Photons from a Quantum DotMar 18 2011Control of single photon wave-packets is an important resource for developing hybrid quantum systems which are composed of different physical systems interacting via photons. Here we extend this control to triggered photons emitted by a quantum dot, temporally ... More
Variations on the Concept of Topological TransitivityJan 21 2016We describe various strengthenings of the concept of topological transitivity. Especially when one departs from the family of invertible systems, a number of interesting properties arise. We present the architecture of implications among ten reasonable ... More
On the time delay in binary systemsJan 19 2005Jan 28 2005The aim of this paper is to study the time delay on electromagnetic signals propagating across a binary stellar system. We focus on the antisymmetric gravitomagnetic contribution due to the angular momentum of one of the stars of the pair. Considering ... More
Binary black hole coalescence in the large-mass-ratio limit: the hyperboloidal layer method and waveforms at null infinityJul 27 2011Oct 12 2011We compute and analyze the gravitational waveform emitted to future null infinity by a system of two black holes in the large mass ratio limit. We consider the transition from the quasi-adiabatic inspiral to plunge, merger, and ringdown. The relative ... More
Compact radio cores: from the first black holes to the lastSep 06 2004One of the clearest signs of black hole activity is the presence of a compact radio core in the nuclei of galaxies. With the Square Kilometer Array (SKA) these cores can be used to study the evolution of black holes throughout the universe and even to ... More
Impact of Numerical Relativity information on effective-one-body waveform modelsMar 20 2017We present a comprehensive comparison of the spin-aligned effective-one-body (EOB) waveform model of Nagar et al. [Phys. Rev. D93, 044046 (2016)], informed using 40 numerical-relativity (NR) datasets, against a set of 149, $\ell=m=2$, NR waveforms freely ... More
Reflections on equicontinuityDec 09 2011We study different conditions which turn out to be equivalent to equicontinuity for a transitive compact Hausdorff flow with a general group action. Among them are a notion of "regional" equicontinuity, also known as "Furstenberg" condition, and the condition ... More
Factorization and resummation: A new paradigm to improve gravitational wave amplitudes. II: the higher multipolar modesJan 08 2018The factorization and resummation approach of Nagar and Shah~[Phys.~Rev.~D~94 (2016), 104017], designed to improve the strong-field behavior of the post-Newtonian (PN) residual waveform amplitudes $f_{\ell m}$'s entering the effective-one-body, circularized, ... More
Horizon-absorption effects in coalescing black-hole binaries: An effective-one-body study of the non-spinning caseJul 03 2012Dec 19 2012We study the horizon absorption of gravitational waves in coalescing, circularized, nonspinning black hole binaries. The horizon absorbed fluxes of a binary with a large mass ratio (q=1000) obtained by numerical perturbative simulations are compared with ... More
Accuracy and effectualness of closed-form, frequency-domain waveforms for non-spinning black hole binariesSep 29 2010Dec 14 2010The coalescences of binary black hole (BBH) systems, here taken to be non-spinning, are among the most promising sources for gravitational wave (GW) ground-based detectors, such as LIGO and Virgo. To detect the GW signals emitted by BBHs, and measure ... More
Binary black hole merger in the extreme mass ratio limitDec 15 2006Feb 09 2007We discuss the transition from quasi-circular inspiral to plunge of a system of two nonrotating black holes of masses $m_1$ and $m_2$ in the extreme mass ratio limit $m_1m_2\ll (m_1+m_2)^2$. In the spirit of the Effective One Body (EOB) approach to the ... More
Measurability of the tidal polarizability of neutron stars in late-inspiral gravitational-wave signalsMar 20 2012The gravitational wave signal from a binary neutron star inspiral contains information on the nuclear equation of state. This information is contained in a combination of the tidal polarizability parameters of the two neutron stars and is clearest in ... More
Radio-Quiet AGN and the Transient Radio SkyFeb 15 2011Jul 22 20118.4-GHZ radio imaging study of an optically selected sample of early type Seyfert galaxies; comparison of images taken at two epochs reveals possible variation in the nuclear radio flux density in five of them over a seven year period. It is shown that ... More
Clustering of advected passive sliders on a fluctuating surfaceMar 29 2004We study the clustering properties of advected, non-interacting,passive scalar particles in a Burgers fluid with noise, a problem which maps to that of passive sliding particles moving under gravity on a surface evolving through the Kardar-Parisi-Zhang ... More
Dynamics of Induced SystemsDec 07 2014In this paper, we study the dynamical properties of actions on the space of compact subsets of the phase space. More precisely, if $X$ is a metric space, let $2^X$ denote the space of non-empty compact subsets of $X$ provided with the Hausdorff topology. ... More
Modeling the complete gravitational wave spectrum of neutron star mergersApr 07 2015Aug 17 2015In the context of neutron star mergers, we study the gravitational wave spectrum of the merger remnant using numerical relativity simulations. Postmerger spectra are characterized by a main peak frequency $f_2$ related to the particular structure and ... More
Dynamical excitation of space-time modes of compact objectsJan 14 2008Mar 06 2008We discuss, in the perturbative regime, the scattering of Gaussian pulses of odd-parity gravitational radiation off a non-rotating relativistic star and a Schwarzschild Black Hole. We focus on the excitation of the $w$-modes of the star as a function ... More
Aluminum Abundances, Deep Mixing and the Blue-Tail Second-Parameter Effect in the Globular Clusters M 3 and M 13Feb 29 2000May 19 2000We explore the relatiohsip between deep mixing on the red-giant branch and the second parameter that gives rise to the extended blue tail seen on the horizontal branch of the globular cluster M 13. We use the [Al/Fe] values of 96 RGB stars and the [Na/Fe] ... More
Boundary-induced abrupt transition in the symmetric exclusion processApr 26 2008Jun 16 2008We investigate the role of the boundary in the symmetric simple exclusion process with competing nonlocal and local hopping events. With open boundaries, the system undergoes a first order phase transition from a finite density phase to an empty road ... More
Near-IR dust and line emission from the central region of Mrk1066: Constraints from Gemini NIFSDec 31 2009Jan 08 2010We present integral field spectroscopy of the inner 350 pc of the Mrk1066 obtained with Gemini NIFS at a spatial resolution of 35 pc. This high spatial resolution allowed us to observe, for the first time in this galaxy, an unresolved dust concentration ... More
Accurate numerical simulations of inspiralling binary neutron stars and their comparison with effective-one-body analytical modelsMar 20 2011Oct 12 2011Binary neutron-star systems represent one of the most promising sources of gravitational waves. In order to be able to extract important information, notably about the equation of state of matter at nuclear density, it is necessary to have in hands an ... More
Quasiuniversal properties of neutron star mergersFeb 25 2014Jun 06 2014Binary neutron star mergers are studied using nonlinear 3+1 numerical relativity simulations and the analytical effective-one-body (EOB) model. The EOB model predicts quasiuniversal relations between the mass-rescaled gravitational wave frequency and ... More
Nonlinear absorption and dispersion in fiber-taper-coupled silicon photonic crystal microresonatorsDec 01 2004A technique is demonstrated which efficiently transfers light between a tapered standard single-mode optical fiber and a high-Q, ultra-small mode volume, silicon photonic crystal resonant cavity. Cavity mode quality factors of 47000 are measured, and ... More
Fabrication-tolerant high quality factor photonic crystal microcavitiesDec 09 2003A two-dimensional photonic crystal microcavity design supporting a wavelength-scale volume resonant mode with a calculated quality factor (Q) insensitive to deviations in the cavity geometry at the level of Q~2x10^4 is presented. The robustness of the ... More
A microelectromechanically controlled cavity optomechanical sensing systemApr 04 2012Microelectromechanical systems (MEMS) have been applied to many measurement problems in physics, chemistry, biology and medicine. In parallel, cavity optomechanical systems have achieved quantum-limited displacement sensitivity and ground state cooling ... More
Ricci flow of unwarped and warped product manifoldsAug 10 2009Sep 16 2009We analyse Ricci flow (normalised/un-normalised) of product manifolds --unwarped as well as warped, through a study of generic examples. First, we investigate such flows for the unwarped scenario with manifolds of the type $\mathbb S^n\times \mathbb S^m$, ... More
On the static Lovelock black holesJan 20 2012May 28 2013We consider static spherically symmetric Lovelock black holes and generalize the dimensionally continued black holes in such a way that they asymptotically for large r go over to the d-dimensional Schwarzschild black hole in dS/AdS spacetime. This means ... More
Financial crises and the evaporation of trustNov 16 2009Trust lies at the crux of most economic transactions, with credit markets being a notable example. Drawing on insights from the literature on coordination games and network growth, we develop a simple model to clarify how trust breaks down in financial ... More
Flexible Byzantine Fault ToleranceApr 22 2019Existing Byzantine fault tolerant (BFT) protocols work in a homogeneous model where a service administrator picks a set of assumptions (timing model and the fraction of Byzantine faults) and imposes these assumptions on all clients using the service. ... More
Particle-in-Cell simulation of two-dimensional electron velocity shear driven instability in relativistic domainMay 30 2016We carry out Particle-in-Cell (PIC) simulations to study the instabilities associated with a 2-D sheared electron flow configuration against a neutralizing background of ions. Both weak and strong relativistic flow velocities are considered. In the weakly ... More
Effect of finite beam width on current separation in beam plasma system: Particle-in-Cell simulationsAug 31 2015Sep 10 2015The electron beam propagation in a plasma medium is susceptible to several instabilities. In the relativistic regime typically the weibel instability leading to the current separation dominates. The linear instability analysis is carried out for a system ... More
Dynamic Assessments, Matching and Allocation of TasksFeb 07 2016Sep 13 2016In many two-sided markets, each side has incomplete information about the other but has an opportunity to learn (some) relevant information before final matches are made. For instance, clients seeking workers to perform tasks often conduct interviews ... More
Relations between Information and Estimation in Scalar Lévy ChannelsApr 27 2014Fundamental relations between information and estimation have been established in the literature for the scalar Gaussian and Poisson channels. In this work, we demonstrate that such relations hold for a much larger class of observation models. We introduce ... More
Nearly-optimal Robust Matrix CompletionJun 23 2016In this paper, we consider the problem of Robust Matrix Completion (RMC) where the goal is to recover a low-rank matrix by observing a small number of its entries out of which a few can be arbitrarily corrupted. We propose a simple projected gradient ... More
Optical fiber coupling to planar photonic crystal microcavitiesMay 13 2004A technique is demonstrated which efficiently transfers light between a tapered standard single-mode optical fiber and a resonant mode of a high-Q photonic crystal cavity with mode volume less than a cubic wavelength in size. Cavity mode quality factors ... More
Curved non-relativistic spacetimes, Newtonian gravitation and massive matterMar 09 2015Nov 01 2015There is significant recent work on coupling matter to Newton-Cartan spacetimes with the aim of investigating certain condensed matter phenomena. To this end, one needs to have a completely general spacetime consistent with local non-relativisitic symmetries ... More
Symmetries and charges of general relativity at null boundariesJul 30 2018Nov 12 2018We study general relativity at a null boundary using the covariant phase space formalism. We define a covariant phase space and compute the algebra of symmetries at the null boundary by considering the boundary-preserving diffeomorphisms that preserve ... More