Results for "C. Bhattacharya"

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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
Dynamics of rotating Bose-Einstein condensates probed by Bragg scatteringJun 06 2006Gaseous Bose-Einstein condensates (BECs) have become an important test bed for studying the dynamics of quantized vortices. In this work we use two-photon Doppler sensitive Bragg scattering to study the rotation of sodium BECs. We analyze the microscopic ... 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
Study of Direct Photon plus Jet production in CMS Experiment at \sqrt{s}=14 TeVMay 18 2007Oct 24 2007We present simulation results of $\gamma$ + Jet analysis using CMS (Compact Muon Solenoid) Object-Oriented software at the Large Hadron Collider (LHC) center of mass energy $\sqrt{s}$=14 TeV. The study of direct photon production helps in validating the ... 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
LAMBDA: Large Area Modular BaF2 Detector Array for the measurement of high energy gamma raysOct 11 2007A large BaF2 detector array along with its dedicated CAMAC electronics and VME based data acquisition system has been designed, constructed and installed successfully at VECC, Kolkata for studying high energy gamma rays (E>8 MeV). The array consists of ... More
Tripartite entanglement detection through tripartite quantum steering in one-sided and two-sided device-independent scenariosApr 26 2017Jul 18 2018In the present work, we study tripartite quantum steering of quantum correlations arising from two local dichotomic measurements on each side in the two types of partially device-independent scenarios: $1$-sided device-independent scenario where one of ... More
Convex geometry of Markovian Lindblad dynamics and witnessing non-MarkovianityMay 28 2018We develop a theory of linear witnesses for detecting non-Markovianity, based on the geometric structure of the set of Choi states for all Markovian evolutions having Lindblad type generators. We show that the set of all such Markovian Choi states form ... More
A Non-Gaussian, Nonparametric Structure for Gene-Gene and Gene-Environment Interactions in Case-Control Studies Based on Hierarchies of Dirichlet ProcessesApr 24 2017It is becoming increasingly clear that complex interactions among genes and environmental factors play crucial roles in triggering complex diseases. Thus, understanding such interactions is vital, which is possible only through statistical models that ... 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
Infinite Families of Simple Holomorphic Eta QuotientsJan 01 2017We address the problem of constructing a simple holomor- phic eta quotient of a given level N . Such constructions are known for all cubefree N . Here, we provide such constructions for arbitrarily large prime power levels. As a consequence, we obtain ... More
A new proposal regarding the heat generated by gravity in locally accelerating framesJan 28 2014For Rindler observers accelerating close to the horizon in local patches around a spacetime point, the matter-energy passing through the horizon increases the entropy and heat energy. Jacobson has showed that the Einstein equation can be derived from ... More
Comparison of decoherence and Zeno dynamics from the context of weak measurement for a two level atom tunneling through squeezed vacuumMar 31 2014Oct 22 2014Decay parameter of coherence and population inversion are calculated from the master equation of a two level atom tunneling through a squeezed vacuum. Using those parameters, the timescales for decoherence and zeno effect are calculated in the weak measurement ... More
Study of Dissipative Collisions of $^{20}$Ne ($\sim$7-11 MeV/nucleon) + $^{27}$AlAug 22 2006The inclusive energy distributions of complex fragments (3 $\leq$Z $\leq$ 9) emitted in the reactions $^{20}$Ne (145, 158, 200, 218 MeV) + $^{27}$Al have been measured in the angular range 10$^{o}$ - 50$^{o}$. The fusion-fission and the deep-inelastic ... 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
An iterative procedure for general probability measures to obtain I-projections onto intersections of convex setsJul 03 2006The iterative proportional fitting procedure (IPFP) was introduced formally by Deming and Stephan in 1940. For bivariate densities, this procedure has been investigated by Kullback and R\"{u}schendorf. It is well known that the IPFP is a sequence of successive ... More
Variations in the Cyclotron Resonant Scattering Features during 2011 outburst of 4U 0115+63Jun 10 2015Aug 20 2015We study the variations in the Cyclotron Resonant Scattering Feature (CRSF) during 2011 outburst of the high mass X-ray binary 4U 0115+63 using observations performed with Suzaku, RXTE, Swift and INTEGRAL satellites. The wide-band spectral data with low ... More
Dissipative collisions in $^{16}$O + $^{27}$Al at E$_{lab}$=116 MeVJul 15 2002The inclusive energy distributions of fragments (3$\leq$Z$\leq$7) emitted in the reaction $^{16}$O + $^{27}$Al at $E_{lab} = $116 MeV have been measured in the angular range $\theta_{lab} $= 15$^\circ$ - 115$^\circ$. A non-linear optimisation procedure ... More
Implementation of quantum search algorithm using classical Fourier opticsOct 05 2001Feb 01 2002We report on an experiment on Grover's quantum search algorithm showing that {\em classical waves} can search a $N$-item database as efficiently as quantum mechanics can. The transverse beam profile of a short laser pulse is processed iteratively as the ... More
Lattice Resistance to Dislocation Motion at the NanoscaleApr 28 2008Aug 06 2008In this letter we propose a model that demonstrates the effect of free surface on the lattice resistance experienced by a moving dislocation in nanodimensional systems. This effect manifests in an enhanced velocity of dislocation due to the proximity ... 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
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
Antiferromagnetic Coupling between Surface and Bulk Magnetization and Anomalous Magnetic Transport in Electro-deposited Co FilmFeb 17 2016We report an interesting magnetic behavior of a Co film (thickness ~ 350 {\AA}) grown on Si/Ti/Cu buffer layer by electro-deposition (ED) technique. Using depth sensitive X-ray reflectivity and polarized neutron reflectivity (PNR) we observed two layer ... More
The central point source in G76.9+1.0Jun 01 2011We describe the serendipitous discovery of a radio point source in a 618 MHz image of the supernova remnant(SNR) G76.9+1.0. The SNR has a bipolar structure and the point source is located near a faint bridge of emission joining the two lobes of emission. ... More
Magnetoelectricity at room temperature in Bi0.9-xTbxLa0.1FeO3 systemJun 02 2004Magnetoelectric compounds with the general formula, Bi0.9-xRxLa0.1FeO3 (R =Gd, Tb, Dy, etc.), have been synthesized. These show the coexistence of ferroelectricity and magnetism, possess high dielectric constant and exhibit magnetoelectric coupling at ... More
Shape of the 8B Alpha and Neutrino SpectraMar 13 2000Jun 19 2000The beta-delayed alpha spectrum from the decay of 8B has been measured with a setup that minimized systematic uncertainties that affected previous measurements. Consequently the deduced neutrino spectrum presents much smaller uncertainties than the previous ... 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
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
Heavy-light Mesons and Baryons with b quarksDec 19 1999Jul 26 2001We present lattice results for the spectrum of mesons containing one heavy quark and of baryons containing one or two heavy quarks. The calculation is done in the quenched approximation using the NRQCD formalism for the heavy quark. We analyze the dependence ... 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
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
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
Early optical and millimeter observations of GRB 030226 afterglowDec 18 2003Jan 13 2004The CCD magnitudes in Johnson $UBV$ and Cousins $RI$ photometric passbands for the afterglow of the long duration GRB 030226 are presented. Upper limits of a few mJy to millimeter wave emission at the location of optical are obtained over the first two ... 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
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
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
Cosmic evolution with a general Gaussian type scale factorNov 24 2017May 17 2018Here we present a simple model of cosmic evolution in Einstein gravity, with the cosmic substratum being composed of an inhomogeneous and anisotropic fluid. The scale factor is supposed to be of Gaussian type. In this framework we show the existence of ... More
Constraining some Horndeski gravity theoriesJul 13 2016Feb 05 2017We discuss two spherically symmetric solutions admitted by the Horndeski (or scalar tensor) theory in the context of solar system and astrophysical scenarios. One of these solutions is derived for Einstein-Gauss-Bonnet gravity, while the other originates ... More
Explaining GRB prompt emission with sub-photospheric dissipation and ComptonizationSep 16 2019Even though the observed spectra for GRB prompt emission is well constrained, no single radiation mechanism can robustly explain its distinct non-thermal nature. Here we explore the radiation mechanism with the photospheric emission model using our Monte ... 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
On the viscosity solutions to a class of nonlinear degenerate parabolic differential equationsOct 11 2016Mar 30 2017In this work, we show existence and uniqueness of positive solutions of $H(Du, D^2u)+\chi(t)|Du|^\Gamma-f(u)u_t=$ in $\Omega\times(0, T)$ and $u=h$ on its parabolic boundary. The operator $H$ satisfies certain homogeneity conditions, $\Gamma>0$ and depends ... More
Intelligent Subset Selection of Power Generators for Economic DispatchSep 08 2017Sustainable and economical generation of electrical power is an essential and mandatory component of infrastructure in today's world. Optimal generation (generator subset selection) of power requires a careful evaluation of various factors like type of ... 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
Over-rotation intervals of bimodal interval mapsAug 20 2019We describe all possible bimodal over-twist patterns. In particular, we give an algorithm allowing one to determine what the left endpoint of the over-rotation interval of a given bimodal map is. We then define a new class of polymodal interval maps called ... 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
Posterior Convergence of Gaussian and General Stochastic Process Regression Under Possible MisspecificationsOct 24 2018In this article, we investigate posterior convergence in nonparametric regression models where the unknown regression function is modeled by some appropriate stochastic process. In this regard, we consider two setups. The first setup is based on Gaussian ... More
Reductions of Galois representations for slopes in $(1,2)$Apr 01 2015We describe the semi-simplification of the mod $p$ reduction of certain crystalline two dimensional local Galois representations of slopes in the interval $(1,2)$ and all weights. The proof uses the mod $p$ Local Langlands Correspondence for $GL_2(Q_p)$. ... 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
A phase-field study of elastic stress effects on phase separation in ternary alloysApr 16 2019Most of the commercially important alloys are multicomponent, producing multiphase microstructures as a result of processing. When the coexisting phases are elastically coherent, the elastic interactions between these phases play a major role in the development ... More
Deterministically Maintaining a $(2+ε)$-Approximate Minimum Vertex Cover in $O(1/ε^2)$ Amortized Update TimeMay 09 2018Jul 11 2018We consider the problem of maintaining an (approximately) minimum vertex cover in an $n$-node graph $G = (V, E)$ that is getting updated dynamically via a sequence of edge insertions/deletions. We show how to maintain a $(2+\epsilon)$-approximate minimum ... More
Fluctuations in horizon-fluid lead to negative bulk viscosityNov 04 2015Feb 29 2016Einstein equations projected on to a black hole horizon gives rise to Navier-Stokes equations. Horizon-fluids typically possess unusual features like negative bulk viscosity and it is not clear whether a statistical mechanical description exists for such ... More
On Classical and Bayesian Asymptotics in State Space Stochastic Differential EquationsJul 22 2015Nov 11 2018In this article we investigate consistency and asymptotic normality of the maximum likelihood and the posterior distribution of the parameters in the context of state space stochastic differential equations (SDEs). We then extend our asymptotic theory ... More
Can a black hole with conformal scalar hair rotate?Nov 01 2013Mar 20 2014It is shown that, under the separability assumption for the metric, the slow-rotation approximation for the Bocharova-Bronnikov-Melnikov-Bekenstein black hole in general relativity with a conformally coupled scalar field does not work outside the event ... More
A Classification of Configuration Spaces of Planar Robot Arms with Application to a Continuous Inverse Kinematics ProblemSep 30 2013Aug 29 2014Using results on the topology of moduli space of polygons [Jaggi, 92; Kapovich and Millson, 94], it can be shown that for a planar robot arm with $n$ segments there are some values of the base-length, $z$, at which the configuration space of the constrained ... More
Supersymmetry Signals at the LHC under the most favorable SUGRA scenarioJan 17 2011Given that it will take quite some time for the Large Hadron Collider (LHC) to reach its desired luminosity, it is important to investigate the most favorable scenario in which supersymmetry (SUSY) may be discovered at the early runs at the LHC. Our aim ... More
Gaugino mass non-universality in an SO(10) supersymmetric Grand Unified Theory: low-energy spectra and collider signalsMar 24 2009Jan 25 2010We derive the non-universal gaugino mass ratios in a supergravity (SUGRA) framework where the Higgs superfields belong to the non-singlet representations {\bf 54} and {\bf 770} in a SO(10) Grand Unified Theory (GUT). We evaluate the ratios for the phenomenologically ... More
Finite entropy characterizes topological rigidityFeb 04 2003Let X_1 and X_2 be mixing connected algebraic dynamical systems with the Descending Chain Condition. We show that every equivariant continuous map X_1 to X_2 is affine (that is, X_2 is topologically rigid) if and only if the system X_2 has finite topological ... More
Dark Energy Constraints from Galaxy Cluster Peculiar VelocitiesDec 01 2007Apr 25 2008Future multifrequency microwave background experiments with arcminute resolution and micro-Kelvin temperature sensitivity will be able to detect the kinetic Sunyaev-Zeldovich (kSZ) effect, providing a way to measure radial peculiar velocities of massive ... More
On the viscosity solutions to some nonlinear elliptic equationsMar 16 2015Oct 11 2016We consider viscosity solutions of a class of nonlinear degenerate elliptic equations on bounded domains. We prove comparison principles and a priori supremum bounds for the solutions. We also address the eigenvalue problem and, in many instances, show ... 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.
A Phragmén-Lindelöf property of viscosity solutions to a class of nonlinear, possibly degenerate, parabolic equationsMay 15 2018Jun 28 2018We study Phragm\'en-Lindel\"of properties of viscosity solutions to a class of doubly nonlinear parabolic equations in $\mathbb{R}^n\times (0,T)$. We also include an application to some doubly nonlinear equations.
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
Hard Electron Energy Distribution in the Relativistic Shocks of GRB AfterglowsApr 08 2008Particle acceleration in relativistic shocks is not a very well understood subject. Owing to that difficulty, radiation spectra from relativistic shocks, such as those in GRB afterglows, have been often modelled by making assumptions about the underlying ... More
Magnetic Fields of Neutron StarsNov 13 1999The evolution of the magnetic field is investigated for isolated as well as binary neutron stars. The overall nature of the field evolution is seen to be similar for an initial crustal field and an expelled flux. The major uncertainties of the present ... More
Some Experimental Issues in Financial Fraud Detection: An InvestigationJan 06 2016Financial fraud detection is an important problem with a number of design aspects to consider. Issues such as algorithm selection and performance analysis will affect the perceived ability of proposed solutions, so for auditors and re-searchers to be ... More
Vectored Route-length Minimization - A Heuristic and An Open ConjectureFeb 13 2008Feb 14 2008We propose a simple but interesting graph theoretic problem and posited a heuristic solution procedure, which we have christened as Vectored Route-length Minimization Search (VeRMinS). Basically, it constitutes of a re-casting of the classical 'shortest ... More
Gauge transformation through an accelerated frame of referenceAug 10 2009The Schr\"{o}dinger equation of a charged particle in a uniform electric field can be specified in either a time-independent or a time-dependent gauge. The wave-function solutions in these two gauges are related by a phase-factor reflecting the gauge ... More
Interconnections between equilibrium topology and dynamical quantum phase transitions in a linearly ramped Haldane modelOct 09 2016May 12 2017We study the behavior of Fisher Zeros (FZs) and dynamical quantum phase transitions (DQPTs) for a linearly ramped Haldane model occurring in the subsequent temporal evolution of the same and probe the intimate connection with the equilibrium topology ... More
Topological footprints of the 1D Kitaev chain with long range superconducting pairings at a finite temperatureMar 26 2018We study the 1D Kitaev chain with long range superconductive pairing terms at a finite temperature where the system is prepared in a mixed state in equilibrium with a heat reservoir maintained at a constant temperature $T$. In order to probe the footprint ... More
Emergent topology and dynamical quantum phase transitions in two-dimensional closed quantum systemsJan 14 2017Jan 21 2017We introduce the notion of a dynamical topological order parameter (DTOP) that characterises dynamical quantum phase transitions (DQPTs) occurring in the subsequent temporal evolution of "two dimensional" closed quantum systems, following a quench (or ... More
Quantum mechanical study of a generic quadratically coupled optomechanical systemApr 22 2013Typical optomechanical systems involving optical cavities and mechanical oscillators rely on a coupling that varies linearly with the oscillator displacement. However, recently a coupling varying instead as the square of the mechanical displacement has ... More
Mass function and particle creation in Schwarzschild-de Sitter spacetimeJan 19 2013Dec 05 2013We construct a mass or energy function for the non-Nariai class Schwarzschild-de Sitter black hole spacetime in the region between the black hole and the cosmological event horizons. The mass function is local, positive definite, continuous and increases ... More
Markov Chain Monte Carlo Based on Deterministic TransformationsJun 29 2011Jun 26 2013In this article we propose a novel MCMC method based on deterministic transformations T: X x D --> X where X is the state-space and D is some set which may or may not be a subset of X. We refer to our new methodology as Transformation-based Markov chain ... More
Neutrino absorption by W production in the presence of a magnetic fieldNov 11 2008In this work we calculate the decay rate of the electron type neutrinos into $W$ bosons and electrons in presence of an external uniform magnetic field. The decay rate is calculated from the imaginary part of the $W$ exchange neutrino self-energy diagram ... More
Collision Times in Multicolor Urn Models and Sequential Graph Coloring With Applications to Discrete LogarithmsNov 18 2013May 24 2016Consider an urn model where at each step one of $q$ colors is sampled according to some probability distribution and a ball of that color is placed in an urn. The distribution of assigning balls to urns may depend on the color of the ball. Collisions ... More
Deep Fault Analysis and Subset Selection in Solar Power GridsNov 08 2017Non-availability of reliable and sustainable electric power is a major problem in the developing world. Renewable energy sources like solar are not very lucrative in the current stage due to various uncertainties like weather, storage, land use among ... More
Very badly ordered cycles of interval mapsAug 16 2019We prove that a periodic orbit $P$ with coprime over-rotation pair is an over-twist periodic orbit iff the $P$-linear map has the over-rotation interval with left endpoint equal to the over-rotation number of $P$. We then show that this result fails if ... More
Performance limitation of Si Nanowire solar cells: Effects of nanowire length and surface defectsSep 16 2019In Si nanowire (SiNW) solar cells enhanced light confinement property in addition to decoupling of charge carrier collection and light absorption directions plays a significant role to resolve the draw backs of bulk Si solar cells. In this report we have ... 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
A stochastic rainbow caustic observed with cold atomsJan 25 2001Apr 10 2001We report the direct observation of a novel type of rainbow caustic. In contrast to known examples, this caustic originates from a dissipative, stochastic process. We have observed this using cold ^{87}Rb atoms bouncing inelastically on an evanescent-wave ... More
Elastic and Inelastic Evanescent-Wave Mirrors for Cold AtomsNov 01 2000We report on experiments on an evanescent-wave mirror for cold $^{87}$Rb atoms. Measurements of the bouncing fraction show the importance of the Van der Waals attraction to the surface. We have directly observed radiation pressure parallel to the surface, ... More
Effects of nematic fluctuations on the elastic properties of iron arsenide superconductorsNov 16 2009Sep 02 2010We demonstrate that the changes in the elastic properties of the FeAs systems, as seen in our resonant ultrasound spectroscopy data, can be naturally understood in terms of fluctuations of emerging nematic degrees of freedom. Both the softening of the ... 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
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
Snowmass Energy Frontier Simulations using the Open Science Grid (A Snowmass 2013 whitepaper)Aug 04 2013Oct 02 2013Snowmass is a US long-term planning study for the high-energy community by the American Physical Society's Division of Particles and Fields. For its simulation studies, opportunistic resources are harnessed using the Open Science Grid infrastructure. ... 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 Improved Statistical Accuracy of Low-Order Polynomial Chaos ApproximationsSep 08 2019Polynomial chaos expansion is a popular way to develop surrogate models for stochastic systems with arbitrary random variables. Standard techniques such as Galerkin projection, stochastic collocation, and least squares approximation, are applied to determine ... More
Heat pump without particle transport or external work on the medium achieved by differential thermostatting of the phase spaceMar 28 2016We propose a new mechanism that enables heat flow from a colder region to a hotter region without necessitating either particle transport or external work on the conductor, thereby bypassing the compressor part of a classical heat pump cycle. Our mechanism ... 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
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
Performance improvement in OFDM system by PAPR reductionMay 09 2012Orthogonal Frequency Division Multiplexing (OFDM) is an efficient method of data transmission for high speed communication systems. However, the main drawback of OFDM system is the high Peak to Average Power Ratio (PAPR) of the transmitted signals. OFDM ... More
A Conversation with George G. RoussasApr 13 2011George G. Roussas was born in the city of Marmara in central Greece, on June 29, 1933. He received a B.A. with high honors in Mathematics from the University of Athens in 1956, and a Ph.D. in Statistics from the University of California, Berkeley, in ... More
Reentrant metallic transition at a temperature above Tc at the breakdown of cooperative Jahn-Teller orbital order in perovskite manganitesDec 07 2004We report an interesting reentrant metallic resistivity pattern beyond a characteristic temperature T* which is higher than other such characteristic transition temperatures like T(c)(Curie point), T(N) (Neel point), T(CO) (charge order onset point) or ... More
Thermogeometric study of van der Waals like phase transition in black holes: an alternative approachMar 25 2019It is well-known that the non-extremal anti-de-Sitter (AdS) black holes show various van der Waals type criticalities, such as the $P-V$, $T-S$, $Y-X$, $Q^2-\Psi$ \etc~In these cases, the phase space diagram of the relevant quantities are similar in behaviour ... More
Non-Ergodicity of Nose-Hoover chain thermostat in computationally achievable timeJul 09 2014The widely used Nose-Hoover chain (NHC) thermostat in molecular dynamics simulations is generally believed to impart the canonical distribution as well as quasi- (i.e., space filling) ergodicity on the thermostatted physical system (PS). Working with ... More
Design of Linear Parameter Varying Quadratic Regulator in Polynomial Chaos FrameworkNov 07 2017We present a new theoretical framework for designing linear parameter varying controllers in the polynomial chaos framework. We assume the scheduling variable to be random and apply polynomial chaos approach to synthesize the controller for the resulting ... 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