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Results for "Raunak P. Bhattacharyya"

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Simulating Emergent Properties of Human Driving Behavior Using Multi-Agent Reward Augmented Imitation LearningMar 14 2019Recent developments in multi-agent imitation learning have shown promising results for modeling the behavior of human drivers. However, it is challenging to capture emergent traffic behaviors that are observed in real-world datasets. Such behaviors arise ... More
Pure and Hybrid Evolutionary Computing in Global Optimization of Chemical Structures: from Atoms and Molecules to Clusters and CrystalsAug 31 2015The growth of evolutionary computing (EC) methods in the exploration of complex potential energy landscapes of atomic and molecular clusters, as well as crystals over the last decade or so is reviewed. The trend of growth indicates that pure as well as ... More
Multi-Agent Imitation Learning for Driving SimulationMar 02 2018Simulation is an appealing option for validating the safety of autonomous vehicles. Generative Adversarial Imitation Learning (GAIL) has recently been shown to learn representative human driver models. These human driver models were learned through training ... More
On Production of Hadrons in Proton-Proton Collisions at RHIC and LHC Energies and an ApproachOct 30 2011From the very early days of Particle Physics, both experimental and theoretical studies on proton-proton collisions had occupied the center-stage of attention for very simple and obvious reasons. And this intense interest seems now to be at peak value ... More
Ansatzs, Assumptions and Production of J/$Ψ$-Particles: A Non-`Charmed' Approach vs. the `Charmed' OnesOct 25 2011Mar 30 2012We would attempt, in this work, at dwelling upon some crucial aspects of $J/\Psi$-production in a few high energy nuclear collisions in the light of a non-standard model which is outlined in the text. The underlying physical ideas, assumptions and ansatzs ... More
Production of J/$Ψ$-Particles at RHIC and LHC energies: An Alternative `Psi'-chologyApr 22 2012We attempt here to understand successfully some crucial aspects of $J/\Psi$-production in some high energy nuclear collisions in the light of a non-standard framework outlined in the text. It is found that the results arrived at with this main working ... More
Elastic Neural Networks: A Scalable Framework for Embedded Computer VisionJul 02 2018Oct 02 2018We propose a new framework for image classification with deep neural networks. The framework introduces intermediate outputs to the computational graph of a network. This enables flexible control of the computational load and balances the tradeoff between ... More
Sample dispersion in isotachophoresis with Poiseuille counterflowJun 08 2012Jan 15 2013A particular mode of isotachophoresis (ITP) employs a pressure-driven flow opposite to the sample electromigration direction in order to anchor a sample zone at a specific position along a channel or capillary. We investigate this situation using a two-dimensional ... More
Understanding the New High Energy Data-sets Measured by BESS, CAPRICE and PAMELA on Antiproton Flux and $\bar{P}/P$ RatiosJun 21 2009Jan 14 2010Reliable data from the very recent high-precision measurements on the antiproton fluxes and the antiproton-to-proton ratios by the PAMELA Collaboration at relatively much higher energies are now available. The results with regard to antiproton production ... More
Rapidity Spectra of Heavy Baryons in Nuclear Collisions at Various Energies : A Systematic ApproachNov 09 2010This study aims at understanding the nature of measured data on the rapidity spectra of some heavy baryons [$\Lambda$, $\Lambda$bar, $\Xi^-$ & $\Xi$bar$^+$] produced in the nuclear collisions at some modestly high energies. Furthermore, our objective ... More
Relativistic disc line: a tool to constrain neutron star equation of state modelsSep 20 2017Relativistic iron K$\alpha$ spectral emission line from the inner disc of a neutron star low-mass X-ray binary (LMXB) was first detected in 2007. This discovery opened up new ways to probe strong gravity and dense matter. The past decade has seen detections ... More
X-ray views of neutron star low-mass X-ray binariesFeb 24 2010A neutron star low-mass X-ray binary is a binary stellar system with a neutron star and a low-mass companion star rotating around each other. In this system the neutron star accretes mass from the companion, and as this matter falls into the deep potential ... More
Entropy current and equilibrium partition function in fluid dynamicsDec 01 2013Jul 25 2014Existence of an entropy current with non-negative divergence puts a lot of constraints on the transport coefficients of a fluid, so does the existence of equilibrium. In all the cases we have studied so far we have seen an overlap between these two sets ... More
Measurement of neutron star parameters: a review of methods for low-mass X-ray binariesJan 11 2010Measurement of at least three independent parameters, for example, mass, radius and spin frequency, of a neutron star is probably the only way to understand the nature of its supranuclear core matter. Such a measurement is extremely difficult because ... More
Ways to constrain neutron star equation of state models using relativistic disc linesSep 09 2011Relativistic spectral lines from the accretion disc of a neutron star low-mass X-ray binary can be modelled to infer the disc inner edge radius. A small value of this radius tentatively implies that the disc terminates either at the neutron star hard ... More
A study of accretion discs around rapidly rotating neutron stars in general relativity and its applications to four Low Mass X-ray BinariesDec 07 2001We calculate the accretion disc temperature profiles, disc luminosities and boundary layer luminosities for rapidly rotating neutron stars considering the full effect of general relativity. We compare the theoretical values of these quantities with their ... More
Limits to the Mass and the Radius of the Compact Star in SAX J1808.4--3658 and Their ImplicationsMay 14 2001We show that a survey of equations of state and observations of X-ray pulsations from SAX J1808.4-3658 give 2.27 solar mass as the upper limit of the compact star mass. The corresponding upper limit of the radius comes out to be 9.73 km. We also do a ... More
Simultaneous observations of a pair of kilohertz QPOs and a plausible 1860 Hz QPO from an accreting neutron star systemNov 30 2009We report an indication (3.22 sigma) of ~ 1860 Hz quasi-periodic oscillations from a neutron star low-mass X-ray binary 4U 1636-536. If confirmed, this will be by far the highest frequency feature observed from an accreting neutron star system, and hence ... More
Prospects of detecting Fast Radio Bursts using Indian Radio TelescopesDec 21 2018Fast Radio Bursts (FRBs) are short duration highly energetic dispersed radio pulses. We developed a generic formalism (Bera {\em et al.}, 2016) to estimate the FRB detection rate for any radio telescope with given parameters. By using this model, we estimated ... More
An inverse problem for the magnetic Schrödinger operator on Riemannian manifolds from partial boundary dataOct 09 2018We consider the inverse problem of recovering the magnetic and potential term of a magnetic Schr\"{o}dinger operator on certain compact Riemannian manifolds with boundary from partial Dirichlet and Neumann data on suitable subsets of the boundary. The ... More
Fast Radio Bursts from neutron stars plunging into black holesNov 24 2017Fast radio bursts (FRBs) are millisecond-duration intense radio flares occurring at cosmological distances. Many models have been proposed to explain these topical astronomical events, but none has so far been confirmed. Here we show that a novel way ... More
Timing properties of XB 1254-690May 19 2006Feb 02 2007We analyze archival Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) data of the low mass X-ray binary (LMXB) system XB 1254-690. We calculate colour-colour diagram, hardness-intensity diagram and power spectra of this source, associate ... More
Temperature Profiles and Spectra of Accretion Disks around Rapidly Rotating Neutron StarsMay 09 2002We calculate temperature profiles and X-ray spectra of accretion disks around rapidly rotating neutron stars considering the full effect of general relativity. Computed disk temperatures and luminosities are compared with the EXOSAT data to constrain ... More
Millisecond X-Ray Pulsar SAX J1808.4-3658: Limits to the Mass and the Radius of the Compact StarDec 07 2001We predict from a survey of equations of state and observations of X-ray pulsations from SAX J1808.4-3658, that the upper limit of the mass of the compact star is 2.27 solar mass. The corresponding upper limit of the radius comes out to be 9.73 km. We ... More
Gamma-ray Flare of PKS 1222+216 in 2010: Effect of Jet Dynamics at the Recollimation ZoneApr 25 2014The $\gamma$-ray flare of PKS 1222+216, observed in June 2010, is interpreted as an outcome of jet dynamics at recollimation zone. We obtained the $\gamma$-ray light-curves in three different energy bands, namely, 100--300 MeV, 300 MeV--1 GeV and 1--3 ... More
Analyzing Non-Extensivity of $η$-spectra in Relativistic Heavy Ion Collisions at $\sqrt{s_{NN}}=200$ GeVNov 05 2009The transverse momentum spectra of secondary $\eta$ particles produced in $P+P$, $D+Au$ and $Au+Au$ interactions at $\sqrt{s_{NN}}=200$ GeV at different centralities have been studied in the light of a non-extensive thermodynamical approach. The results ... More
Forced Fluid Dynamics from GravityMay 30 2008Jan 12 2009We generalise the computations of arXiv:0712.2456 to generate long wavelength, asymptotically locally AdS_5 solutions to the Einstein-dilaton system with a slowly varying boundary dilaton field and a weakly curved boundary metric. Upon demanding regularity, ... More
Sputtering based epitaxial growth and modeling of Cu/Si thin filmsAug 20 2015Epitaxial copper thin films were deposited by magnetron sputtering. The adatoms during deposition are influenced by deposition parameters which cause variations in thin film properties. XRD and FESEM studies were done to get an insight into the growth ... More
Phrase Pair Mappings for Hindi-English Statistical Machine TranslationOct 05 2017Nov 10 2017In this paper, we present our work on the creation of lexical resources for the Machine Translation between English and Hindi. We describes the development of phrase pair mappings for our experiments and the comparative performance evaluation between ... More
Lexical Resources for Hindi Marathi MTMar 04 2017In this paper we describe some ways to utilize various lexical resources to improve the quality of statistical machine translation system. We have augmented the training corpus with various lexical resources such as IndoWordnet semantic relation set, ... More
Neutrino Oscillation as Coupled vibrationNov 28 2002Neutrino oscillation is visualized as coupled vibrations. Unlike existing models describing neutrino oscillations, our model involving a single fundamental mass parameter $m$ and first discussed in the context of a possible boson oscillation demonstrates ... More
Spectroscopic modelling of four neutron star low-mass X-ray binaries using CLOUDYMar 13 2019Low-mass X-ray binaries (LMXBs) have a wide range of X-ray properties which can be utilised to reveal many physical conditions of the associated accretion discs. We use the spectral synthesis code CLOUDY to perform a detailed modelling of neutron star ... More
Low lying spectroscopy of odd-odd $^{146}$EuMar 26 2013Apr 12 2013Electron Capture (EC) decay of $^{146}$Gd($\it{t_{1/2}}$ = 48d) to the low lying states of $^{146}$Eu has been studied using high-resolution $\gamma$ ray spectroscopy. The $^{146}$Gd activity was produced by ($\alpha$, 2n) reaction at E$_{\alpha}$ = 32 ... More
Dynamics in quantum Ising chain driven by inhomogeneous transverse magnetizationDec 13 2016Nov 01 2017We study the dynamics caused by transport of transverse magnetization in one dimensional transverse Ising chain at zero temperature. We observe that a class of initial states having product structure in fermionic momentum-space and satisfying certain ... More
Rapidity Spectra of the Secondaries Produced in Heavy Ion Collisions and the Constituent Picture of the ParticlesDec 03 2004Dec 21 2004The present study is both a reanalysis and an extension of the approach initiated by Eremin and Voloshin(referenced in the text). We attempt to interpret here the rapidity-spectra of the various particles produced in both $Pb+Pb$ and $Au+Au$ collisions ... More
On the Special Significance of the Latest PAMELA Results in Astroparticle PhysicsAug 03 2012In continuation of their earlier measurements, the PAMELA group reported data on antiproton flux and $\bar{P}/P$ ratios in 2010 at much higher energies. In past we had dealt with these specific aspects of PAMELA data in great detail and each time we captured ... More
Thermonuclear X-ray bursts from the 401 Hertz accreting pulsar IGR J17498-2921: indication of burning in confined regionsFeb 21 2012We use the 2011 Rossi X-ray Timing Explorer (RXTE) proportional counter array (PCA) data of the 401 Hz accreting pulsar and burster IGR J17498-2921 to perform timing analysis and time-resolved spectroscopy of 12 thermonuclear X-ray bursts. We confirm ... More
On some properties of Deuteron and Antideuteron production in high energy lead-lead collisions at 158A GeVMar 18 2014We would attempt here to understand some properties of the transverse momentum ($p_T$) and rapidity ($y$) spectra on production of deuteron ($d$) and antideuteron($\overline{d}$) in lead-lead $(Pb+Pb)$ collisions at 158A GeV recently reported by NA49 ... More
Supersymmetric States in M5/M2 CFTsFeb 09 2007Oct 01 2007We propose an exact, finite $N$ formula for the partition function over $1/4^{th}$ BPS states in the conformal field theory on the world volume of $N$ coincident M5 branes and $1/8^{th}$ BPS states in the theory of $N$ coincident M2 branes. We obtain ... More
The $p_T$-Spectra of Some Non-pion Secondaries in High Energy NN to NA/AA Collisions and the Combinational ApproachJun 11 2003In continuation of our perusal of the studies on transverse momentum spectra for the main varieties of secondaries from a consistent and comprehensive phenomenological approach, we propose to take up here -- after a successful completion of reporting ... More
Distinguishing general relativity from Chern-Simons gravity using gravitational wave polarizationsDec 01 2018Quasi-normal modes (QNMs) uniquely characterize the final black-hole. Till now, only the QNM frequency and damping time are used to test General relativity. In this work, we show explicitly that another property of the QNMs --- their polarization --- ... More
Quasinormal modes as a distinguisher between general relativity and f(R) gravity: Charged black-holesMar 20 2018Sep 05 2018The ring-down phase of black-hole perturbations is governed by the Quasi-Normal modes (QNM) and offer valuable insight into the nature of the objects emitting them. In General relativity, we identify a dimensionless parameter that can estimate the charge ... More
The Effect of Transient Accretion on the Spin-Up of Millisecond PulsarsDec 15 2016A millisecond pulsar is a neutron star that has been substantially spun up by accretion from a binary companion. A previously unrecognized factor governing the spin evolution of such pulsars is the crucial effect of non-steady or transient accretion. ... More
Circular orbits in Kerr-Taub-NUT spacetime and their implications for accreting black holes and naked singularitiesJan 14 2019It has recently been proposed that the accreting collapsed object GRO J1655--40 could contain a non-zero gravitomagnetic monopole, and hence could be better described with the more general Kerr-Taub-NUT (KTN) spacetime, instead of the Kerr spacetime. ... More
Observation of the Berezinskii-Kosterlitz-Thouless transition in Boron-doped diamond filmsJun 07 2017The occurrence of the Berezinskii-Kosterlitz-Thouless (BKT) transition is investigated in heavily boron-doped nanocrystalline diamond films through a combination of current-voltage and resistance measurements. We observe a robust BKT transition in the ... More
Path integral action of a particle with the generalized uncertainty principle and correspondence with noncommutativityJan 08 2019The existence of an observer independent minimum length scale can lead to the modification of the Heisenberg uncertainty principle to the generalized uncertainty principle. This in turn would be responsible for the modification of the Hamiltonian describing ... More
Inverse boundary value problem of determining up to second order tensors appear in the lower order perturbations of the polyharmonic operatorJun 12 2017May 24 2018We consider the following perturbed polyharmonic operator $\Lc(x,D)$ of order $2m$ defined in a bounded domain $\Omega \subset \mathbb{R}^n, n\geq 3$ with smooth boundary, as \begin{equation*} \Lc(x,D) \equiv (-\Delta)^m + \sum_{j,k=1}^{n}A_{jk} D_{j}D_{k} ... More
Fractional amplitude of kilohertz quasi-periodic oscillation from 4U 1728-34: evidence of decline at higher energiesSep 16 2012A kilohertz quasi-periodic oscillation (kHz QPO) is an observationally robust high-frequency timing feature detected from neutron star low-mass X-ray binaries (LMXBs). This feature can be very useful to probe the superdense core matter of neutron stars, ... More
Highly coherent kilohertz quasi-periodic oscillations from a neutron star X-ray binary EXO 1745-248Jan 01 2011Mar 03 2011We report the discovery ($20\sigma$) of kilohertz quasi-periodic oscillations (kHz QPOs) at ~ 690 Hz from the transient neutron star low-mass X-ray binary EXO 1745-248. We find that this is a lower kHz QPO, and systematically study the time variation ... More
Time evolution of probability density function of gamma ray burst (GRB) - a possible indication of turbulence origin of GRBNov 11 2011Gamma ray burst (GRB) time series is a non-stationary time series with all its statistical properties varying with time. Considering that each GRB is a different manifestation of the same stochastic process we studied the time dependent as well as time ... More
Timing and spectral study of XB 1254-690 using new RXTE PCA dataJul 20 2011We have analyzed the new Rossi X-ray Timing Explorer Proportional Counter Array data of the atoll neutron star (NS) low-mass X-ray binary (LMXB) system XB 1254-690. The colour-colour diagram shows that the source was in the high-intensity banana state. ... More
Anisotropic Local Stress and Particle Hopping in a Deeply Supercooled LiquidJan 31 2005The origin of the microscopic motions that lead to stress relaxation in deeply supercooled liquid remains unclear. We show that in such a liquid the stress relaxation is locally anisotropic which can serve as the driving force for the hopping of the system ... More
Indian monsoon rainfall is higher in epochs of higher solar activity: a wavelet cross-spectral analysisNov 11 2004Using the Morlet continuous wavelet transform on data over the period 1871-1990, it is found that the global wavelet cross spectra between two solar activity indices and seven major Indian monsoon rainfall time series show significant power around the ... More
Coexisting Order in the Pseudogap State of CupratesJan 11 2007A pseudogap is shown to be a magnetic diffuson (MD) in a state with classical localization order coexisting with Quantum Peierls (QP) order. A soft quantum localization mode, a phason, ensures scale invariance with strong correlations among different ... More
Hadron transverse momentum distributions of the Tsallis normalized and unnormalized statisticsMar 14 2019The exact analytical formulas for the transverse momentum distributions of the Bose-Einstein, Fermi-Dirac and Maxwell-Boltzmann statistics of particles with nonzero mass in the framework of the Tsallis normalized and Tsallis unnormalized (also known as ... More
A Non-supersymmetric Interpretation of the CDF e+e-γγ+ missing E_T EventJun 21 1996The $\eegg$ event reported recently by the CDF Collaboration has been interpreted as a signal of supersymmetry in several recent papers. In this article, we report on an alternative non-supersymmetric interpretation of the event using an extension of ... More
Extensive broadband X-ray monitoring during the formation of a giant radio jet base in Cyg X-3 with AstroSatJan 11 2018We present X-ray spectral and timing behavior of Cyg X-3 as observed by AstroSat during the onset of a giant radio flare on 01-02 April 2017. Within a time-scale of few hours, the source shows a transition from the hypersoft state (HPS) to a more luminous ... More
Semiconductor-metal transition in semiconducting bilayer sheets of transition metal dichalcogenidesMar 30 2012Aug 17 2012Using first-principles calculations we show that the band gap of bilayer sheets of semiconducting transition metal dichalcogenides (TMDs) can be reduced smoothly by applying vertical compressive pressure. These materials undergo a universal reversible ... More
Evidence for Harmonic Content and Frequency Evolution of Oscillations during the Rising Phase of X-ray Bursts from 4U 1636-536Sep 14 2005Dec 03 2005We report on a study of the evolution of burst oscillation properties during the rising phase of X-ray bursts from 4U 1636--536 observed with the proportional counter array (PCA) onboard the Rossi X-Ray Timing Explorer (RXTE). We present evidence for ... More
Investigation of Superconducting Gap Structure in HfIrSi using muon spin relaxation/rotationMar 22 2019Appearance of strong spin-orbit coupling (SOC) is apparent in ternary equiatomic compounds with 5$d$-electrons due to the large atomic radii of transition metals. SOC plays a significant role in the emergence of unconventional superconductivity. Here ... More
Probing the superconducting ground state of ZrIrSi: A $μ$SR studyMar 20 2019The superconducting ground state of newly reported ZrIrSi is probed by means of $\mu$SR technique along with resistivity measurement. The occurrence of superconductivity at $T_\mathrm{C}$ = 1.7 K is confirmed by resistivity measurement. ZF-$\mu$SR study ... More
Theoretical model of structure-dependent conductance crossover in disordered carbonJul 27 2012We analyze the effects of sp^2/sp^3 bond-aspect ratio on the transport properties of amorphous carbon quasi-1D structures where structural disorder varies in a very non-linear manner with the effective bandgap. Using a tight-binding approach the calculated ... More
Comparative study of anomalous size dependence of charged and neutral solute diffusion in waterFeb 23 2018In this work, we perform a comparative study of the size dependence of diffusion of charged and neutral solutes in water. The neutral solute in water shows a nonmonotonicity in the size dependence of diffusion. This is usually connected to the well known ... More
Spectral Clustering and Block Models: A Review And A New AlgorithmAug 07 2015We focus on spectral clustering of unlabeled graphs and review some results on clustering methods which achieve weak or strong consistent identification in data generated by such models. We also present a new algorithm which appears to perform optimally ... More
Subsampling bootstrap of count features of networksDec 10 2013Nov 17 2015Analysis of stochastic models of networks is quite important in light of the huge influx of network data in social, information and bio sciences, but a proper statistical analysis of features of different stochastic models of networks is still underway. ... More
Spreading of thermonuclear flames on the neutron star in SAX J1808.4-3658: an observational toolApr 03 2006We analyse archival Rossi X-Ray Timing Explorer (RXTE) proportional counter array (PCA) data of thermonuclear X-ray bursts from the 2002 outburst of the accreting millisecond pulsar SAX J1808.4-3658. We present evidence of nonmonotonic variations of oscillation ... More
Signature of Temporary Burning Front Stalling from a Non-Photospheric Radius Expansion Double-peaked BurstMar 16 2006Non-photospheric-radius-expansion (non-PRE) double-peaked bursts may be explained in terms of spreading (and temporary stalling) of thermonuclear flames on the neutron star surface, as we argued in a previous study of a burst assuming polar ignition. ... More
Extremely asymmetric shears band in 143SmSep 19 2018Dec 24 2018A dipole sequence has been observed and investigated in the 143 Sm nucleus populated through the heavy-ion induced fusion-evaporation reaction and studied using the Indian National Gamma Array (INGA) as the detection system. The sequence has been established ... More
Role of p-induced population of medium mass(A $\sim$ 150) neutron rich nucleiDec 24 2014Excitation functions were measured by stacked-foil activation technique for the $^{150}$Nd(p, xpyn) reaction using 97.65$%$ enriched $^{150}$Nd target. Measurement up to $\sim$50$%$ above barrier and down to 18$%$ below the barrier was performed using ... More
Temporally Coherent Bayesian Models for Entity Discovery in Videos by Tracklet ClusteringSep 22 2014Feb 06 2015A video can be represented as a sequence of tracklets, each spanning 10-20 frames, and associated with one entity (eg. a person). The task of \emph{Entity Discovery} in videos can be naturally posed as tracklet clustering. We approach this task by leveraging ... More
Paradigm Shifts and a Possible Resolution of the PAMELA-Paradox in Astroparticle PhysicsJun 21 2009Very recently, PAMELA Collaboration has formally reported two sets of data on positron and antiproton flux measurements done at very high energies and with unprecedented accuracy. The reports reveal a puzzle of great topical interest and importance : ... More
Phenomenological bound on the viscosity of the hadron resonance gasJul 09 2018Oct 08 2018We have explored some phenomenological issues during calculations of transport coefficients for hadronic matter, produced in the experiments of heavy ion collisions. Here, we have used an ideal hadron resonance gas model to demonstrate the issues. On ... More
A Unified Framework for Testing Linear-Invariant PropertiesOct 24 2010The study of the interplay between the testability of properties of Boolean functions and the invariances acting on their domain which preserve the property was initiated by Kaufman and Sudan (STOC 2008). Invariance with respect to F_2-linear transformations ... More
A random walk with heavy flavoursJul 11 2013We focus on evaluating transport coefficients like drag and diffusion of heavy quarks (HQ) passing through Quark Gluon Plasma using perturbative QCD (pQCD). Experimental observable like nuclear suppression factor (RAA) of HQ is evaluated for both zero ... More
A Single Zone Synchrotron Model for Flares of PKS 1510-089Sep 08 2016PKS 1510-089 is one of the most variable blazars. Very high energy gamma ray emission from this source was observed by H.E.S.S. during March-April 2009 and by MAGIC from February 3 to April 3, 2012 quasi-simultaneously with multi-wavelength flares. The ... More
The Critical Point Equation on Kenmotsu and almost Kenmotsu manifoldsDec 09 2018In this paper, we have studied the critical point equation (shortly, CPE) within the frame-work of Kenmotsu and almost Kenmotsu manifold satisfying certain nullity conditions. First, we prove that a complete Kenmotsu metric satisfies the CPE is Einstein ... More
A leading-order comparison between fluid-gravity and membrane-gravity dualitiesJul 13 2018Feb 03 2019In this note, we have compared two different perturbation techniques that are used to generate dynamical black-brane solutions to Einstein equation in presence of negative cosmological constant. One is the `derivative expansion', where the gravity solutions ... More
Memory-constrained Vectorization and Scheduling of Dataflow Graphs for Hybrid CPU-GPU PlatformsNov 29 2017The increasing use of heterogeneous embedded systems with multi-core CPUs and Graphics Processing Units (GPUs) presents important challenges in effectively exploiting pipeline, task and data-level parallelism to meet throughput requirements of digital ... More
Heat Kernel Expansion and Extremal Kerr-Newmann Black Hole Entropy in Einstein-Maxwell TheoryApr 18 2012We compute the second Seely-DeWitt coefficient of the kinetic operator of the metric and gauge fields in Einstein-Maxwell theory in an arbitrary background field configuration. We then use this result to compute the logarithmic correction to the entropy ... More
Finite bias dependent evolution of superconductor-insulator transition and Zero Bias Conductance in boron doped nanodiamond filmsJun 21 2016Oct 14 2017We report on transport features in heavily boron doped nanocrystalline diamond (BNCD) films which are not seen in conventional (s-wave) granular superconductors. Observations include an anomalous resistance peak near to the superconducting transition ... More
Observation of impedance oscillations in single walled carbon nanotube bundles excited by high frequency signalsApr 10 2015We report experimental observation of impedance oscillations in single-walled carbon nanotubes measured from 100 MHz to 65 GHz on coplanar wave guides and a power law dependence of the differential conductance with bias voltage. From the crossover of ... More
Conductivity crossover in nano-crystalline diamond films: Realization of a disordered superlattice-like structureJul 25 2012We present the electrical transport characteristics of a batch of nano-crystalline diamond films of varying nitrogen concentrations and explain the conduction mechanism by the disordered quasi-superlattice model applied to semiconductor heterostructures. ... More
Feature Based Fuzzy Rule Base Design for Image ExtractionJun 16 2012In the recent advancement of multimedia technologies, it becomes a major concern of detecting visual attention regions in the field of image processing. The popularity of the terminal devices in a heterogeneous environment of the multimedia technology ... More
String Multiplets from an Invariant 2-BraneDec 09 1998Jan 06 1999We study a three-dimensional gauge theory obtained from the dimensional reduction of a D4-brane worldvolume theory in the background of space-time moduli. An SL(3) symmetry in this theory, which acts on fields as well as coupling constants, is identified. ... More
Spin-glass-like state in GdCu: role of phase separation and magnetic frustrationNov 22 2011We report investigations on the ground state magnetic properties of intermetallic compound GdCu through dc magnetization measurements. GdCu undergoes first order martensitic type structural transition over a wide temperature window of coexisting phases. ... More
Equilibrium study of Protein/DNA Complexes from Crystal Structure DataJul 14 2006From the crystal structure data and using the concept of equilbrium statistical mechanics we show how to calculate the thermodynamics of protein/DNA complexes. We apply the method to the TATA-box binding protein (TBP)/TATA sequence complex. We have estimated ... More
Effect of Fibonacci Modulation On SuperconductivityOct 20 2005We have studied finite-sized single band models with short range pairing interactions between electrons in presence of diagonal Fibonacci modulation in one dimension. Two models, namely the attractive Hubbard model and the Penson-Kolb model, have been ... More
Dissipative superfluid dynamics from gravityJan 17 2011Mar 21 2011Charged asymptotically AdS black branes in five dimensions are sometimes unstable to the condensation of charged scalar fields. For fields of infinite charge and squared mass -4 Herzog was able to analytically determine the phase transition temperature ... More
Effect of strain on electronic and thermoelectric properties of few layers to bulk MoS$_{2}$Jul 29 2014The sensitive dependence of electronic and thermoelectric properties of MoS$_2$ on the applied strain opens up a variety of applications in the emerging area of straintronics. Using first principles based density functional theory calculations, we show ... More
Interplay between crystallization and glass transition in binary Lennard-Jones mixturesJul 29 2013In this work we explore the interplay between crystallization and glass transition in different binary mixtures by changing their inter-species interaction length and also the composition. We find that only those systems which form bcc crystal in the ... More
The Incompressible Non-Relativistic Navier-Stokes Equation from GravityOct 09 2008Jul 20 2009We note that the equations of relativistic hydrodynamics reduce to the incompressible Navier-Stokes equations in a particular scaling limit. In this limit boundary metric fluctuations of the underlying relativistic system turn into a forcing function ... More
Curved Membrane Solutions in D=11 SupergravityJun 04 2002Jun 24 2002We present a class of static membrane solutions, with non-flat worldvolume geometry, in the eleven dimensional supergravity with source terms. This class of solutions contains supersymmetric as well as a large class of non-supersymmetric configurations. ... More
Orientational and Translational Hopping in Supercooled Liquids and Glasses : Correlated Dynamics in a Free Energy LandscapeNov 02 2001Nov 03 2001Orientational relaxation (OR) in a viscous, glassy liquid is investigated by carrying out extensive NPT molecular dynamics simulations of isolated ellipsoids in a glass forming binary mixture. Near the glass transition, the OR occurs mainly via hopping ... More
General relativistic spectra of accretion disks around rotating neutron starsNov 28 2000General relativistic spectra from accretion disks around rotating neutron stars in the appropriate space-time geometry for several different equation of state, spin rates and mass of the compact object have been computed. The analysis involves the computation ... More
A study of a tilted thin inner accretion disk around a spinning black holeNov 14 2018Feb 01 2019The inner part of a thin accretion disk around a Kerr black hole can serve as an important tool to study the physics of the strong gravity regime. A tilt in such a disk with respect to the black hole spin axis is particularly useful for this purpose, ... More
Rainbow black hole thermodynamics and the generalized uncertainty principleMay 17 2018We study the phase transition of rainbow inspired higher dimensional Schwarzschild black hole incorporating the effects of the generalized uncertainty principle. First, we obtain the relation between the mass and Hawking temperature of the rainbow inspired ... More
Black holes in presence of cosmological constant: Second order in 1/DMay 01 2018Jul 03 2018We have extended the results of arXiv:1704.06076 upto second subleading order in an expansion around large dimension D. Unlike the previous case, there are non-trivial metric corrections at this order. Due to our `background-covariant' formalism, the ... More
Network organization of coopetitive genetic influences on cortical morphologiesFeb 09 2018Brain can be represented as a network, where regions are the nodes and relations between the regions are edges. Within a network, co-existence of cooperative and competitive relationships between different nodes is called coopetition. Inter-regional genetic ... More
X-ray spectral state evolution in IGR J17091-3624 and comparison of its heartbeat oscillation properties with those of GRS 1915+105May 24 2011Jan 21 2014In this work, we study the X-ray timing and spectral evolution of the transient low mass X-ray binary IGR J17091-3624 during first 66 days of its 2011 outburst. We present results obtained from observations with two instruments, Rossi X-ray Timing Explorer ... More
Small Hairy Black Holes in $AdS_5 \times S^5$May 07 2010We study small hairy black holes in a consistent truncation of ${\cal N}=8$ gauged supergravity that consists of a single charged scalar field interacting with the metric and a U(1) gauge field. Small very near extremal RNAdS black holes in this system ... More