Results for "C. Bhattacharya"

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The third conformer of graphane: A first principles DFT based studyJul 12 2010We propose, on the basis of our first principles density functional based calculations, a new isomer of graphane, in which the C-H bonds of a hexagon alternate in 3-up, 3-down fashion on either side of the sheet. This 2D puckered structure called 'stirrup' ... More
Electronic and Structural Analysis of a Stable Hydrogenated BN sheet (BHNH): A First Principles Based ApproachJun 15 2010From first-principles density functional calculations, we study the structural and electronic properties of a stable hydrogenated BN sheet, having formula unit BHNH. In the optimized BHNH structure, the H atoms stabilize on the B and N sites, alternating ... More
Unsupervised Classification of PolSAR Data Using a Scattering Similarity Measure Derived from a Geodesic DistanceDec 01 2017In this letter, we propose a novel technique for obtaining scattering components from Polarimetric Synthetic Aperture Radar (PolSAR) data using the geodesic distance on the unit sphere. This geodesic distance is obtained between an elementary target and ... More
Estimation of Higher Order Moments for Compound Models of Clutter by Mellin TransformSep 28 2008The compound models of clutter statistics are found suitable to describe the nonstationary nature of radar backscattering from high-resolution observations. In this letter, we show that the properties of Mellin transform can be utilized to generate higher ... More
Effect of In-Medium Meson Masses on Nuclear Matter PropertiesDec 18 1998Masses of hadrons (baryons as well as mesons) are modified in the nuclear medium because of their interactions. In this paper we investigate the effect of in-medium meson masses on the properties of the nuclear matter. The calculations are performed in ... More
Higher Order Moments Generation by Mellin Transform for Compound Models of ClutterAug 16 2008The compound models of clutter statistics are found suitable to describe the nonstationary nature of radar backscattering from high-resolution observations. In this letter, we show that the properties of Mellin transform can be utilized to generate higher ... More
Sharp change over from compound nuclear fission to shape dependent quasi fissionSep 17 2008Fission fragment mass distribution has been measured from the decay of $^{246}$Bk nucleus populating via two entrance channels with slight difference in mass asymmetries but belonging on either side of the Businaro Gallone mass asymmetry parameter. Both ... More
Nonparametric statistics on manifolds with applications to shape spacesMay 21 2008This article presents certain recent methodologies and some new results for the statistical analysis of probability distributions on manifolds. An important example considered in some detail here is the 2-D shape space of k-ads, comprising all configurations ... More
Dissipation of angular momentum in light heavy ion collisionSep 08 2003Jan 07 2004The inclusive energy distributions of fragments (4$\leq$Z$\leq$7) emitted in the reactions $^{16}$O (116 MeV) + $^{27}$Al, $^{28}$Si, $^{20}$Ne (145 MeV) + $^{27}$Al, $^{59}$Co have been measured in the angular range $\theta_{lab} $= 10$^\circ$ - 65$^\circ$. ... More
Exploring N-rich phases in LixNy clusters for hydrogen storage at nano-scaleJun 22 2015Jun 24 2015We have performed cascade genetic algorithm and ab initio atomistic thermodynamics under the framework of first-principles density functional theory to study the (meta-)stability of a wide range of LixNy clusters. We found that hybrid xc-functional is ... More
Evolution of the Modern Phase of Written Bangla: A Statistical StudyOct 06 2013Active languages such as Bangla (or Bengali) evolve over time due to a variety of social, cultural, economic, and political issues. In this paper, we analyze the change in the written form of the modern phase of Bangla quantitatively in terms of character-level, ... More
Deformation in 28Si* produced via 16O + 12C reactionFeb 04 2013The energy spectra of the $\alpha$ particles emitted in the reactions $^{16}$O (7-10 MeV/nucleon) + $^{12}$C have been measured in the center of mass angular range of 25$^\circ$ $\lesssim \theta_{c.m.} \lesssim$ 70$^\circ$. The experimental energy spectra ... More
Evidence of large nuclear deformation of $^{32}$S$^{*}$ formed in $^{20}$Ne + $^{12}$C reactionAug 18 2006Deformations of hot composite $^{32}$S$^{*}$ formed in the reaction $^{20}$Ne ($\sim$ 7 -- 10 MeV/nucleon) + $^{12}$C have been estimated from the respective inclusive $\alpha$-particle evaporation spectra. The estimated deformations for $^{32}$S$^{*}$ ... More
An Analytical Framework for Understanding the Intensity of Religious FundamentalismNov 09 2017This paper examines the process of emergence of religious fundamentalism through development parameters. Therefore this research work reflects an analytical discussion on how the level of religious fundamentalism can be explained by the economic, political ... More
Finiteness of irreducible holomorphic eta quotients of a given levelFeb 08 2016Sep 18 2017We show that for any positive integer $N$, there are only finitely many holomorphic eta quotients of level $N$, none of which is a product of two holomorphic eta quotients other than 1 and itself. This result is an analog of Zagier's conjecture/ Mersmann's ... More
Bioclimating Modelling: A Machine Learning PerspectiveJun 18 2013Many machine learning (ML) approaches are widely used to generate bioclimatic models for prediction of geographic range of organism as a function of climate. Applications such as prediction of range shift in organism, range of invasive species influenced ... More
Measurement of Giant Dipole Resonance width at low temperature: A new experimental perspectiveDec 02 2011Dec 05 2011The systematic evolution of the giant dipole resonance (GDR) width in the temperature region of 0.9 ~ 1.4 MeV has been measured experimentally for 119Sb using alpha induced fusion reaction and employing the LAMBDA high energy photon spectrometer. The ... More
Extreme nuclear shapes examined via Giant Dipole Resonance lineshapes in hot light mass systemJun 03 2010The influence of alpha clustering on nuclear reaction dynamics is investigated using the giant dipole resonance (GDR) lineshape studies in the reactions 20Ne (Elab=145,160 MeV) + 12C and 20Ne (Elab=160 MeV) + 27Al, populating 32S and 47V, respectively. ... More
Direct Evidence of Washing out of Nuclear Shell EffectsApr 17 2015Constraining excitation energy at which nuclear shell effect washes out has important implications on the production of super heavy elements and many other fields of nuclear physics research. We report the fission fragment mass distribution in alpha induced ... More
Modifying the Yamaguchi Four-Component Decomposition Scattering Powers Using a Stochastic DistanceApr 04 2015Model-based decompositions have gained considerable attention after the initial work of Freeman and Durden. This decomposition which assumes the target to be reflection symmetric was later relaxed in the Yamaguchi et al. decomposition with the addition ... More
Superconductivity-induced Magnetic Modulation in a Ferromagnet Through an Insulator in LaCaMnO3\SrTiO3\YBa2Cu3O7-δ Hybrid HeterostructuresApr 22 2014Coexistence of ferromagnetic and superconducting orders and their interplay in ferromagnet-superconductor heterostructures is a topic of intense research. While it is well known that proximity of a ferromagnet suppresses superconducting order in the superconductor, ... More
Quadri-allele frequency spectrum in a coalescent topology for mutations in non-constant population sizeMay 11 2014The sample frequency spectrum of a segregating site is the probability distribution of a sample of alleles from a genetic locus, conditional on observing the sample to have more than one clearly different phenotypes. We present a model for analyzing quadri-allele ... More
Relative weak injectivity of operator system pairsJul 09 2013May 11 2014The concept of a relatively weakly injective pair of operator systems is introduced and studied in this paper, motivated by relative weak injectivity in the C*-algebra category. E. Kirchberg \cite{Kr} proved that the C*-algebra $C^*(\mathbb{f}_\infty)$ ... More
Irreducibility of a holomorphic eta quotient is determinableFeb 09 2016Sep 16 2018We show that a holomorphic eta quotient has only finitely many factors. We also provide an algorithm for checking irreducibility of holomorphic eta quotients by constructing an upper bound for the minimum of the levels of the proper factors of a reducible ... More
Finiteness of simple holomorphic eta quotients of a given weightFeb 09 2016Jul 08 2016We provide a simplified proof of Zagier's conjecture / Mersmann's theorem which states that of any particular weight, there are only finitely many holomorphic eta quotients, none of which is an integral rescaling of another eta quotient or a product of ... More
Evolution and Computational Learning Theory: A survey on Valiant's paperDec 17 2013Darwin's theory of evolution is considered to be one of the greatest scientific gems in modern science. It not only gives us a description of how living things evolve, but also shows how a population evolves through time and also, why only the fittest ... More
On the Curvature ODE associated to the Ricci flowOct 17 2013In the vector space of algebraic curvature operators we study the reaction ODE $$\frac{dR}{dt} = R^2+R^{#}= Q(R)$$ which is associated to the evolution equation of the Riemann curvature oper- ator along the Ricci flow. More precisely, we analyze the stability ... More
Large deviation for extremes of branching random walk with regularly varying displacementsFeb 16 2018We consider discrete time branching random walk on real line where the displacements of particles coming from the same parent are allowed to be dependent and jointly regularly varying. Using the one large bunch asymptotics, we derive large deviation for ... More
Periodic points of algebraic actions of discrete groupsMar 02 2017Let $\Gamma$ be a countable group. A $\Gamma$-action on a compact abelian group $X$ by continuous automorphisms of $X$ is called Noetherian if the dual of $X$ is Noetherian as a ${\mathbb Z}(\Gamma)$-module. We prove that any Noetherian action of a finitely ... More
Diversity Handling In Evolutionary LandscapeNov 15 2014The search ability of an Evolutionary Algorithm (EA) depends on the variation among the individuals in the population. Maintaining an optimal level of diversity in the EA population is imperative to ensure that progress of the EA search is unhindered ... More
Light charged particle emission from hot $^{32}$S$^{*}$ formed in $^{20}$Ne + $^{12}$C reactionJul 01 2008Nov 11 2008Inclusive energy distributions for light charged particles ($p, d, t$ and $\alpha$) have been measured in the $^{20}$Ne (158, 170, 180, 200 MeV) + $^{12}$C reactions in the angular range 10$^{o}$ -- 50$^{o}$. Exclusive light charged particle energy distribution ... More
Detecting level crossings without looking at the spectrumApr 26 2006Sep 14 2006In many physical systems it is important to be aware of the crossings and avoided crossings which occur when eigenvalues of a physical observable are varied using an external parameter. We have discovered a powerful algebraic method of finding such crossings ... More
Charge transfer and interfacial magnetism in (LaNiO3)n/(LaMnO3)2 superlatticesJan 30 2013Jul 02 2013(LaNiO3)n/(LaMnO3)2 superlattices were grown using ozone-assisted molecular beam epitaxy, where LaNiO3 is a paramagnetic metal and LaMnO3 is an antiferromagnetic insulator. The superlattices exhibit excellent crystallinity and interfacial roughness of ... More
A new interacting two fluid model and its consequencesJan 03 2017Jan 31 2017In the background of a homogeneous and isotropic spacetime with zero spatial curvature, we consider interacting scenarios between two barotropic fluids, one is the pressureless dark matter (DM) and the other one is dark energy (DE), in which the equation ... More
On the Nature of the Rapidity-Spectra at RHIC and Some Other EnergiesSep 27 2009May 08 2010On the basis of the Grand Combinational Model (GCM) outlined and somewhat detailed in the text, we have attempted to capture here the several interesting assorted characteristics of the rapidity-spectra of the major varieties of secondaries produced in ... More
Giant Dipole Resonance Width in near-Sn Nuclei at Low Temperature and High Angular MomentumJan 25 2008High energy gamma-rays in coincidence with low energy yrast gamma-rays have been measured from 113Sb, at excitation energies of 109 and 122 MeV, formed by bombarding 20Ne on 93Nb at projectile energies of 145 and 160 MeV respectively to study the role ... More
Onset of deformation at $N = 112$ in Bi nucleiApr 19 2012The high spin states in $^{195}$Bi has been studied by $\gamma$-ray spectroscopic method using the $^{181}$Ta($^{20}$Ne, 6n) fusion evaporation reaction at 130 MeV. The $\gamma\gamma$ coincidence data were taken using an array of 8 clover HPGe detectors. ... More
Prompt atmospheric neutrino flux from the various QCD modelsNov 17 2016Nov 19 2016We evaluate the prompt atmospheric neutrino flux using the different QCD models for heavy quark production including the $b$ quark contribution. We include the nuclear correction and find it reduces the fluxes by $10 \% - 50\%$ according to the models. ... More
Prompt atmospheric neutrino fluxNov 16 2016We evaluate the prompt atmospheric neutrino flux including nuclear correction and $B$ hadron contribution in the different frameworks: NLO perturbative QCD and dipole models. The nuclear effect is larger in the prompt neutrino flux than in the total charm ... More
Exploring semiconductor substrates for Silicene epitaxyAug 22 2013We have carried out first-principles based DFT calculation on electronic properties of silicene monolayer on various (111) semi-conducting surfaces. We find that the relative stability and other properties of the silicene overlayer depends sensitively ... More
Prompt atmospheric neutrino fluxes: perturbative QCD models and nuclear effectsJul 01 2016Nov 01 2016We evaluate the prompt atmospheric neutrino flux at high energies using three different frameworks for calculating the heavy quark production cross section in QCD: NLO perturbative QCD, $k_T$ factorization including low-$x$ resummation, and the dipole ... More
Characterization of fragment emission in ^{20}Ne (7 - 10 MeV/nucleon) + ^{12}C reactionsApr 10 2007Jul 23 2007The inclusive energy distributions of the complex fragments (3 $\leq$ Z $\leq$ 7) emitted from the bombardment of ^{12}C by ^{20}Ne beams with incident energies between 145 and 200 MeV have been measured in the angular range 10$^{o} \leq \theta_{lab} ... More
Survival of orbiting in $^{20}$Ne (7 - 10 MeV/nucleon) + $^{12}$C reactionsMar 01 2005Jul 20 2005The inclusive energy distributions of fragments with Z $\geq$ 3 emitted from the bombardment of $^{12}$C by $^{20}$Ne beams with incident energies between 145 and 200 MeV have been measured in the angular range $\theta_{lab} \sim$ 10$^\circ$ - 50$^\circ$. ... More
Fusion of light exotic nuclei at near-barrier energies : effect of inelastic excitationFeb 08 2002The effect of inelastic excitation of exotic light projectiles (proton- as well as neutron-rich) $^{17}$F and $^{11}$Be on fusion with heavy target has been studied at near-barrier energies. The calculations have been performed in the coupled channels ... More
Band gap engineering by functionalization of BN sheetJun 17 2011From first principles calculations, we investigate the stability and physical properties of single layer h-BN sheet chemically functionalized by various groups viz. H, F, OH, CH3, CHO, CN, NH2 etc. We find that full functionalization of h-BN sheet with ... More
Fusion of light proton-rich exotic nuclei at near-barrier energiesFeb 08 2002We study theoretically fusion of the light proton-rich exotic nuclei $^{17}$F and $^8$B at near-barrier energies in order to investigate the possible role of breakup processes on their fusion cross sections. To this end, coupled channel calculations are ... More
Asymptotics of viscosity solutions to some doubly nonlinear parabolic equationsJul 31 2015Mar 23 2017We study asymptotic decay rates of viscosity solutions to some doubly nonlinear parabolic equations, including Trudinger's equation. We also prove a Phragm\'en-Lindel\"of type result and show its optimality.
Non-minimally coupled dark fluid in Schwarzschild spacetimeJul 19 2016Apr 07 2017If one assumes a particular form of non-minimal coupling, called the conformal coupling, of a perfect fluid with gravity in the fluid-gravity Lagrangian then one gets modified Einstein field equation. In the modified Einstein equation, the effect of the ... More
Photons from jet - plasma interaction in relativistic heavy ion collisionsJun 25 2008Aug 12 2010We expose the role of collisional energy loss on high $p_T$ photon data measured by PHENIX collaboration by calculating photon yield in jet plasma interaction. The phase space distribution of the participating jet is dynamically evolved by solving Fokker-Planck ... More
Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)Dec 08 2008May 29 2009We calculate transverse momentum distribution of direct photons from various sources by taking into account the initial state momentum anisotropy of {\em Quark-Gluon-Plasma} (QGP) and late stage transverse flow effects. The total photon yield, calculated ... More
Signal Adaptive Variable Selector for the Horseshoe PriorOct 21 2018In this article, we propose a simple method to perform variable selection as a post model-fitting exercise using continuous shrinkage priors such as the popular horseshoe prior. The proposed Signal Adaptive Variable Selector (SAVS) approach post-processes ... More
On the k-Means/Median Cost FunctionApr 18 2017In this work, we study the $k$-means cost function. The (Euclidean) $k$-means problem can be described as follows: given a dataset $X \subseteq \mathbb{R}^d$ and a positive integer $k$, find a set of $k$ centers $C \subseteq \mathbb{R}^d$ such that $\Phi(C, ... More
Mining Statistically Significant Substrings using the Chi-Square StatisticJun 30 2012The problem of identification of statistically significant patterns in a sequence of data has been applied to many domains such as intrusion detection systems, financial models, web-click records, automated monitoring systems, computational biology, cryptology, ... More
Evaluating the Building Blocks of a Dynamically Adaptive Systematic Trading StrategyDec 06 2018Financial markets change their behaviours abruptly. The mean, variance and correlation patterns of stocks can vary dramatically, triggered by fundamental changes in macroeconomic variables, policies or regulations. A trader needs to adapt her trading ... More
A General Asymptotic Framework for Distribution-Free Graph-Based Two-Sample TestsAug 30 2015Apr 16 2019Testing equality of two multivariate distributions is a classical problem for which many non-parametric tests have been proposed over the years. Most of the popular two-sample tests, which are asymptotically distribution-free, are based either on geometric ... More
Stability in Distribution of Randomly Perturbed Quadratic Maps as Markov ProcessesMar 24 2005Iteration of randomly chosen quadratic maps defines a Markov process: X_{n+1}=\epsilon_{n+1}X_n(1-X_n), where \epsilon_n are i.i.d. with values in the parameter space [0,4] of quadratic maps F_{\theta}(x)=\theta x(1-x). Its study is of significance as ... More
Two-Sample Tests Based on Geometric Graphs: Asymptotic Distribution and Detection ThresholdsDec 01 2015May 18 2018In this paper we consider the problem of testing the equality of two multivariate distributions based on geometric graphs, constructed using the inter-point distances between the observations. These include the test based on the minimum spanning tree ... More
State Estimation in Power Distribution Systems Based on Ensemble Kalman FilteringDec 04 2017State estimation in power distribution systems is a key component for increased reliability and optimal system performance. Well understood in transmission systems, state estimation is now an area of active research in distribution networks. While several ... More
Interconnections between equilibrium topology and dynamical quantum phase transitions: a linearly ramped Haldane modelOct 09 2016In order to probe the role of equilibrium topology in dictating the behavior of Fisher Zeros (FZs) and dynamical quantum phase transitions (DQPTs) occurring in the subsequent temporal evolution of a quenched topological model, we invoke upon a linearly ... More
VHDL Modeling of Intrusion Detection & Prevention System (IDPS) A Neural Network ApproachFeb 21 2014The rapid development and expansion of World Wide Web and network systems have changed the computing world in the last decade and also equipped the intruders and hackers with new facilities for their destructive purposes. The cost of temporary or permanent ... More
QoS Aware and Survivable Network Design for Planned Wireless Sensor NetworksOct 21 2011Apr 22 2014We study the problem of wireless sensor network design by deploying a minimum number of additional relay nodes (to minimize network cost) at a subset of given potential relay locations, in order to convey the data from already existing sensor nodes (hereafter ... More
An Estimation Method of Measuring Image Quality for Compressed Images of Human FaceFeb 06 2014Nowadays digital image compression and decompression techniques are very much important. So our aim is to calculate the quality of face and other regions of the compressed image with respect to the original image. Image segmentation is typically used ... More
Resampling in Time Series ModelsJan 05 2012This project revolves around studying estimators for parameters in different Time Series models and studying their assymptotic properties. We introduce various bootstrap techniques for the estimators obtained. Our special emphasis is on Weighted Bootstrap. ... More
Coincidence of Schur multipliers of the Drury-Arveson spaceNov 18 2009Jul 09 2013In a purely multi-variable setting (i.e., the issues discussed in this note are not interesting in the single variable operator theory setting), we show that the coincidence of two operator valued Schur class multipliers of a certain kind on the Drury-Arveson ... More
Sequential Bayesian inference for static parameters in dynamic state space modelsAug 20 2014Jun 27 2017A method for sequential Bayesian inference of the static parameters of a dynamic state space model is proposed. The method is based on the observation that many dynamic state space models have a relatively small number of static parameters (or hyper-parameters), ... More
Stability of Quadratic curvature Functionals at product Einstein manifoldsAug 20 2018Jan 02 2019In this paper, we study Riemannian functionals defined by $L^2$-norms of Ricci curvature, scalar curvature, Weyl curvature, and Riemannian curvature. We try to understand stability of their critical points that are products of Einstein metrics. In particular, ... More
Analytical Modeling of IEEE 802.11 Type CSMA/CA Networks with Short Term UnfairnessJul 24 2016We consider single-hop topologies with saturated transmitting nodes, using IEEE~802.11 DCF for medium access. However, unlike the conventional WiFi, we study systems where one or more of the protocol parameters are different from the standard, and/or ... More
Effect of running coupling on photons from jet - plasma interaction in relativistic heavy ion collisionsJan 20 2011We discuss the role of collisional energy loss on high $p_T$ photon data measured by PHENIX collaboration by calculating photon yield in jet-plasma interaction. The phase space distribution of the participating jet is dynamically evolved by solving Fokker-Planck ... More
Omnibus CLTs for Fréchet means and nonparametric inference on non-Euclidean spacesJun 24 2013Mar 28 2016Two central limit theorems for sample Fr\'echet means are derived, both significant for nonparametric inference on non-Euclidean spaces. The first one, Theorem 2.2, encompasses and improves upon most earlier CLTs on Fr\'echet means and broadens the scope ... More
Dynamical Wormholes in f(R) Theory of GravityJun 12 2015Jun 25 2015Dynamical wormhole solution is formulated in the framework of f(R) modified theory of gravity. A general dynamical spherically symmetric wormhole space time is assumed with specific form of the shape function and scale factor. The behaviour of energy ... More
Coupling a small torsional oscillator to large optical angular momentumApr 17 2013We propose a new configuration for realizing torsional optomechanics: an optically trapped windmill-shaped dielectric interacting with Laguerre-Gaussian cavity modes containing both angular and radial nodes. In contrast to existing schemes, our method ... More
Cold atoms in U(3) gauge potentialsMar 28 2016Jul 29 2016We explore the effects of artificial $U(3)$ gauge potentials on ultracold atoms. We study background gauge fields with both non-constant and constant Wilson loops around plaquettes, obtaining the energy spectra in each case. The scenario of metal-insulator ... More
DNA confined in a two-dimensional strip geometryDec 04 2013Mar 25 2014Semiflexible polymers characterized by the contour length $L$ and persistent length $\ell_p$ confined in a spatial region $D$ have been described as a series of ``{\em spherical blobs}'' and ``{\em deflecting lines}'' by de Gennes and Odjik for $\ell_p ... More
Distributed Weighted Parameter Averaging for SVM Training on Big DataSep 30 2015Two popular approaches for distributed training of SVMs on big data are parameter averaging and ADMM. Parameter averaging is efficient but suffers from loss of accuracy with increase in number of partitions, while ADMM in the feature space is accurate ... More
On the Fermat-Weber Point of a Polygonal ChainApr 17 2010Nov 13 2012In this paper, we study the properties of the Fermat-Weber point for a set of fixed points, whose arrangement coincides with the vertices of a regular polygonal chain. A $k$-chain of a regular $n$-gon is the segment of the boundary of the regular $n$-gon ... More
Jet-photons from an anisotropic {\em Quark-Gluon-Plasma}Jan 07 2010Jul 12 2010We calculate the $p_T$ distributions of jet conversion photons from {\em Quark Gluon Plasma} with pre-equilibrium momentum-space anisotropy. A phenomenological model has been used for the time evolution of hard momentum scale $p_{\rm hard}(\tau)$ and ... More
A large sample test for the length of memory of stationary symmetric stable random fields via nonsingular $\mathbb{Z}^d$-actionsNov 27 2016Nov 27 2017Based on the ratio of two block maxima, we propose a large sample test for the length of memory of a stationary symmetric $\alpha$-stable discrete parameter random field. We show that the power function converges to one as the sample-size increases to ... More
Kirchberg's Factorization Property for Discrete Quantum GroupsDec 29 2015Jul 06 2016We show that the discrete duals of the universal unitary quantum groups and orthogonal quantum groups have Kirchberg's factorization property when n is different from 3.
Critical depinning force and vortex lattice order in disordered superconductorsOct 07 2000We simulate the ordering of vortices and its effects on the critical current in superconductors with varied vortex-vortex interaction strength and varied pinning strengths for a two-dimensional system. For strong pinning the vortex lattice is always disordered ... More
Fission fragment mass distribution in $^{210}$Po and $^{213}$AtJan 03 2018Background: The influence of shell effect on the dynamics of the fusion fission process and it's evolution with excitation energy in the pre-actinide Hg-Pb region in general is a matter of intense research in recent years. In particular, a strong ambiguity ... More
AstroSat and Chandra view of the high soft state of 4U 1630-47 (4U 1630-472): evidence of the disk wind and a rapidly spinning black holeOct 02 2018We present the X-ray spectral and timing analysis of the transient black hole X-ray binary 4U 1630-47, observed with the AstroSat, Chandra and MAXI space missions during its soft X-ray outburst in 2016. The outburst, from the rising phase until the peak, ... More
Defect mediated changes in structural, optical and photoluminescence properties of Ni substituted CeO2Jul 06 2018Local and long range structure, optical and photoluminescence properties of sol-gel synthesized Ce1-xNixO2 nanostructures have been studied. The crystal structure, lattice strain and crystallite size have been analyzed. A decrease in lattice parameter ... More
Assessing Chronic Kidney Disease from Office Visit Records Using Hierarchical Meta-Classification of an Imbalanced DatasetNov 17 2017Chronic Kidney Disease (CKD) is an increasingly prevalent condition affecting 13% of the US population. The disease is often a silent condition, making its diagnosis challenging. Identifying CKD stages from standard office visit records can help in early ... More
Forbidden Transitions in a Magneto-Optical TrapApr 09 2003We report the first observation of a non-dipole transition in an ultra-cold atomic vapor. We excite the 3P-4P electric quadrupole (E2) transition in $^{23}$Na confined in a Magneto-Optical Trap(MOT), and demonstrate its application to high-resolution ... More
High Temperature Asymptotics of Orthogonal Mean-Field Spin GlassesJul 17 2015Aug 20 2015We evaluate the high temperature limit of the free energy of spin glasses on the hypercube with Hamiltonian $H_N(\sigma) = \sigma^T J \sigma$, where the coupling matrix $J$ is drawn from certain symmetric orthogonally invariant ensembles. Our derivation ... More
A Brief Review of Optimal Scaling of the Main MCMC Approaches and Optimal Scaling of Additive TMCMC Under Non-Regular CasesMay 05 2014Jul 25 2017Very recently, Transformation based Markov Chain Monte Carlo (TMCMC) was proposed by Dutta and Bhattcharya (2013) as a much efficient alternative to the Metropolis-Hastings algorithm, Random Walk Metropolis (RWM) algorithm, especially in high dimensions. ... More
Limit Theorems for Monochromatic StarsApr 15 2017Nov 30 2017Let $T(K_{1, r}, G_n)$ be the number of monochromatic copies of the $r$-star $K_{1, r}$ in a uniformly random coloring of the vertices of the graph $G_n$. In this paper we provide a complete characterization of the limiting distribution of $T(K_{1, r}, ... More
Forward charm-production models and prompt neutrinos at IceCubeAug 01 2018Nov 14 2018We investigate the prompt neutrino background at IceCube, as determined from forward charm. We consider the role of intrinsic charm and of a recombination model and show that the contribution of these mechanisms is at most a factor two.
Aggregate Skyline Join Queries: Skylines with Aggregate Operations over Multiple RelationsJun 28 2012The multi-criteria decision making, which is possible with the advent of skyline queries, has been applied in many areas. Though most of the existing research is concerned with only a single relation, several real world applications require finding the ... More
Inference in Ising ModelsJul 25 2015Mar 03 2017The Ising spin glass is a one-parameter exponential family model for binary data with quadratic sufficient statistic. In this paper, we show that given a single realization from this model, the maximum pseudolikelihood estimate (MPLE) of the natural parameter ... More
Monochromatic Subgraphs in Randomly Colored GraphonsJul 18 2017Aug 07 2017Let $T(H, G_n)$ be the number of monochromatic copies of a fixed connected graph $H$ in a uniformly random coloring of the vertices of the graph $G_n$. In this paper we give a complete characterization of the limiting distribution of $T(H, G_n)$, when ... More
On Geometric Ergodicity of Additive and Multiplicative Transformation Based Markov Chain Monte Carlo in High DimensionsDec 03 2013Mar 22 2015Recently Dutta and Bhattacharya (2013) introduced a novel Markov Chain Monte Carlo methodology that can simultaneously update all the components of high dimensional parameters using simple deterministic transformations of a one-dimensional random variable ... More
Local asymptotic minimax risk bounds in a locally asymptotically mixture of normal experiments under asymmetric lossNov 07 2006Local asymptotic minimax risk bounds in a locally asymptotically mixture of normal family of distributions have been investigated under asymmetric loss functions and the asymptotic distribution of the optimal estimator that attains the bound has been ... More
Partitioned Cross-Validation for Divide-and-Conquer Density EstimationAug 31 2016We present an efficient method to estimate cross-validation bandwidth parameters for kernel density estimation in very large datasets where ordinary cross-validation is rendered highly inefficient, both statistically and computationally. Our approach ... More
Exact and Asymptotic Results on Coarse Ricci Curvature of GraphsJun 28 2013Jul 10 2013In this paper we study Ollivier's coarse Ricci-curvature for graphs, and obtain exact formulas for the Ricci-curvature for bipartite graphs and for the graphs with girth at least 5. These are the first formulas for Ricci-curvature which hold for a wide ... More
On Geometric Ergodicity of Additive and Multiplicative Transformation Based Markov Chain Monte Carlo in High DimensionsDec 03 2013Jan 23 2017Recently Dutta and Bhattacharya (2013) introduced a novel Markov Chain Monte Carlo methodology that can simultaneously update all the components of high dimensional parameters using simple deterministic transformations of a one-dimensional random variable ... More
A Brief Tutorial on Transformation Based Markov Chain Monte Carlo and Optimal Scaling of the Additive TransformationJul 04 2013Jan 23 2017We consider the recently introduced Transformation-based Markov Chain Monte Carlo (TMCMC) (Dutta and Bhattacharya (2014)), a methodology that is designed to update all the parameters simultaneously using some simple deterministic transformation of a onedimensional ... More
On Optimal Scaling of Additive Transformation Based Markov Chain Monte CarloJul 04 2013Sep 15 2015Study of diffusion limits of the Metropolis-Hastings algorithm in high dimensions yields useful quantificaton of the scaling of the underlying proposal distribution in terms of the dimensionality. Here we consider the recently introduced Transformation-based ... More
Degree Sequence of Random Permutation GraphsMar 12 2015In this paper we study the degree sequence of the permutation graph $G_{\pi_n}$ associated with a sequence $\pi_n\in S_n$ of random permutations. Joint limiting distributions of the degrees are established using results from graph and permutation limit ... More
Bound States of Pseudo-Dirac Dark MatterDec 07 2018We study the bound-state spectrum in a simple model of pseudo-Dirac dark matter, and examine how the rate of bound-state formation through radiative capture compares to Sommerfeld-enhanced annihilation. We use this model as an example to delineate the ... More