Results for "Neeraj Pradhan"

total 671took 0.10s
Tensor Variable Elimination for Plated Factor GraphsFeb 08 2019A wide class of machine learning algorithms can be reduced to variable elimination on factor graphs. While factor graphs provide a unifying notation for these algorithms, they do not provide a compact way to express repeated structure when compared to ... More
Anisotropic fluid star model in isotropic coordinatesOct 21 2014We present a spherically symmetric solution of the general relativistic field equations in isotropic coordinates for anisotropic neutral fluid, compatible with a super dense star modeling by considering a specific choice of anisotropy factor that includes ... More
Modular organization enhances the robustness of attractor network dynamicsJan 31 2011Modular organization characterizes many complex networks occurring in nature, including the brain. In this paper we show that modular structure may be responsible for increasing the robustness of certain dynamical states of such systems. In a neural network ... More
Koszul property of diagonal subalgebrasJul 28 2013Jul 31 2013Let S=K[x_1,...,x_n] be a polynomial ring over a field K and I a homogeneous ideal in S generated by a regular sequence f_1,f_2,...,f_k of homogeneous forms of degree d. We study a generalization of a result of Conca, Herzog, Trung, and Valla [9] concerning ... More
Ranks of elliptic curves over cyclic cubic, quartic, and sextic extensionsJan 31 2014For a given group $G$ and an elliptic curve $E$ defined over a number field $K$, I discuss the problem of finding $G$-extensions of $K$ over which $E$ gains rank. I prove the following theorem, extending a result of Fearnley, Kisilevsky, and Kuwata: Let ... More
Extremal limits and Bañados-Silk-West effectAug 16 2016A fascinating property of extremal Kerr black hole (BH) is that it could be act as a particle accelerator with infinite high center-of-mass (CM) energy \cite{bsw}. In this note, we would like to discuss about such fascinating result and to point out that ... More
Thermodynamic Products in Extended Phase SpaceMar 24 2016Jun 20 2016We have examined the thermodynamic properties for a variety of spherically symmetric charged-AdS black hole (BH) solutions, including the charged AdS BH surrounded by quintessence dark energy and charged AdS BH in $f(R)$ gravity in \emph{extended phase-space}. ... More
Entropy Product Formula for spinning BTZ Black HoleSep 02 2015We investigate the thermodynamic properties of inner and outer horizons in the background of spinning BTZ(Ba\~{n}ados,Teitelboim and Zanelli) black hole. We compute the \emph{horizon radii product, the entropy product, the surface temperature product, ... More
Black Hole Interior Mass FormulaOct 26 2013May 06 2014We argue by explicit computations that, although the area product, horizon radii product, entropy product and \emph {irreducible mass product} of the event horizon and Cauchy horizon are universal, the \emph{surface gravity product}, \emph{surface temperature ... More
Logarithmic Corrections to the Black Hole Entropy Product of ${\cal H}^{\pm}$ via Cardy FormulaAug 04 2016We compute the logarithmic corrections to the black hole (BH) entropy product of ${\cal H}^{\pm}$ \footnote{ ${\cal H}^{+}$ and ${\cal H}^{-}$ denote outer (event) horizon and inner (Cauchy) horizons} by using \emph{Cardy prescription}. We particularly ... More
P-V Criticality in Conformal Gravity holography in four DimensionsMar 24 2016Jun 15 2016In this work we study the $P-V$ criticality of conformal gravity(CG) holography in four dimensions by considering the cosmological constant as thermodynamic pressure. The main potential point of interest in CG is that there exists a \emph{Rindler parameter ... More
Area Functional Relation for 5D-Gauss-Bonnet-AdS Black HoleMar 24 2016Jul 21 2016We present \emph{area (or entropy) functional relation} for multi-horizons five dimensional (5D) Einstein-Maxwell-Gauss-Bonnet-AdS Black Hole. It has been observed by exact and explicit calculation that some complicated function of two or three horizons ... More
Thermodynamic Product Formula for Hořava Lifshitz Black HoleJun 10 2015We examine the thermodynamic properties of inner and outer horizons in the background of Ho\v{r}ava Lifshitz black hole. We compute the \emph{horizon radii product, the surface area product, the entropy product, the surface temperature product, the Komar ... More
Thermodynamic Products for Sen Black HoleMar 16 2015Feb 27 2016We investigate the properties of inner and outer horizon thermodynamics of Sen black hole(BH) both in \emph{Einstein frame(EF)} and \emph{string frame(SF)}. We also compute area(or entropy) product, area(or entropy) sum of the said BH in EF as well as ... More
Enhancement of coherent light amplification using Anderson localizationJul 23 1998Several aspects of interplay between Anderson localization and coherent amplification/absorption, and aspect of mirrorless laser for a laser-active (amplifying) disordered dielectric medium have been addressed. We have calculated the statistics of the ... More
Enthalpy, Geometric Volume and Logarithmic correction to Entropy for Van-der-Waals Black HoleOct 18 2016If the negative cosmological constant is treated as a dynamical pressure and if the volume be its thermodynamically conjugate variable then the gravitational mass can be expressed as the total gravitational enthalpy rather than the energy. Under these ... More
Two-fluid atmosphere from decelerating to accelerating FRW dark energy modelsOct 29 2012May 03 2013The evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with perfect fluid and dark energy components is studied by generalizing the recent results (Amirhashchi ... More
Accelerating dark energy models with anisotropic fluid in Bianchi type-$VI_{0}$ space-timeSep 17 2012Motivated by the increasing evidence for the need of a geometry that resembles Bianchi morphology to explain the observed anisotropy in the WMAP data, we have discussed some features of the Bianchi type-$VI_{0}$ universes in the presence of a fluid that ... More
Magnetized String Cosmological Model in Cylindrically Symmetric Inhomogeneous Universe with Variable Cosmological-Term $Λ$Aug 01 2007Jul 26 2008Cylindrically symmetric inhomogeneous magnetized string cosmological model is investigated with cosmological term $\Lambda$ varying with time. To get the deterministic solution, it has been assumed that the expansion ($\theta$) in the model is proportional ... More
Mass Independent Entropy Products in Conformal GravityMar 24 2016In this work we investigate the thermodynamic properties of conformal holography in four dimensions. We compute the \emph{area(or entropy) functional} relation for this black hole. We consider both dS and AdS cases. Thermodynamic stability is studied ... More
Circular Geodesics in the Kerr-Newman-Taub-NUT Space-timeFeb 01 2014Jul 04 2015In this paper we investigate the equatorial causal (time-like and null) circular geodesics of the Kerr-Newman-Taub-NUT(Newman-Unti-Tamburino) black hole in four dimensional Lorentzian geometry. The special characteristics of this black hole is that it ... More
Geometric Product Formula for Charged Accelerating Black HoleJun 26 2016We evaluate the geometric product formula i.e. area (or entropy) product formula of outer horizon (${\cal H}^{+}$) and inner horizon (${\cal H}^{-}$) for charged accelerating black hole. We find that mass-independent area functional relation of ${\cal ... More
Area(or Entropy) Product Formula for a Regular Black HoleDec 19 2015Jan 27 2016We compute the area(or entropy) product formula for a regular black hole derived by Ay\'on-Beato and Garc\'ia in 1998\cite{abg}. By explicit and exact calculation, it is shown that the entropy product formula of two physical horizons strictly \emph{depends} ... More
Thermodynamic Product Formula for Taub-NUT Black HoleAug 20 2015We derive various important thermodynamic relations of the inner and outer horizon in the background of Taub-NUT(Newman-Unti-Tamburino) black hole in four dimensional \emph{Lorentzian geometry}. We compare these properties with the properties of Reissner ... More
R package imputeTestbench as a Testbench to compare missing value imputation methodsAug 01 2016This paper discusses about R package imputeTestbench , which provides a testbench to do comparison of methods used for missing data imputation. This package validates and compares a proposed imputation method with other default methods like historic mean ... More
An Algebraic Proof for the Identities for Degree of Syzygies in Numerical SemigroupSep 25 2011In a recent paper by L. Fel two new identities for the degree of syzygies are given. We present an algebraic proof of them, using only basic homological algebra tools. We also extend these results.
An irreducibility criterion for integer polynomialsDec 06 2016Let $f(x) = \sum\limits _{i=0}^{n} a_i x^i $ be a polynomial with coefficients from the ring $\mathbb{Z}$ of integers satisfying either $(i)$ $0 < a_0 \leq a_{1} \leq \cdots \leq a_{k-1} < a_{k} < a_{k+1} \leq \cdots \leq a_n$ for some $k$, $0 \leq k ... More
Causality and Correlations between BSE and NYSE indexes: A Janus Faced RelationshipAug 28 2016We study the multi-scale temporal correlations and causality connections between the New York Stock Exchange (NYSE) and Bombay Stock Exchange (BSE) monthly average closing price indexes for a period of 300 months, encompassing the time period of the liberalisation ... More
On the Estimation of Pointwise DimensionDec 09 2013Jan 16 2014Our goal in this paper is to develop an effective estimator of fractal dimension. We survey existing ideas in dimension estimation, with a focus on the currently popular method of Grassberger and Procaccia for the estimation of correlation dimension. ... More
Phase statistics of light wave reflected from one-dimensional optical disordered media and its effects on light transport propertiesDec 28 2015Light wave reflection from optical disordered media is always associate with its phase, and the phase statistics influence the reflection statistics. We report a detailed numerical study of the statistics of the reflection coefficient RR* and its associated ... More
Horizon Straddling ISCOs in Spherically Symmetric String Black HolesSep 30 2012Jul 04 2015The causal geodesics in the equatorial plane of a static extremal charged black holes in heterotic string theory are examined with regard to their geodesic stability, and compared with similar geodesics in the non-extremal situation. Extremization of ... More
CFT and Logarithmic Corrections of Black Hole Entropy Product FormulaJul 06 2016We examine the \emph{effects of CFT} (conformal field theory) on the logarithmic corrections of black hole (BH) entropy product formula of outer horizon and inner horizon by explicitly giving several examples. We also argue that logarithmic corrections ... More
Regular Black Holes as Particle AcceleratorsFeb 12 2014Oct 10 2014We investigate the possibility of arbitrarily high energy in the center of mass(CM) frame of colliding particles in the vicinity of the infinite red-shift surface of the spherically symmetric, static charged regular black holes (Bardeen black hole, Ay\'{o}n-Beato ... More
Area Products and Mass Formula for Kerr-Newman-Taub-NUT Space-timeOct 29 2013Jul 16 2015We derive area product, entropy product, area sum and entropy sum of the event horizon and Cauchy horizons for Kerr-Newman-Taub-NUT(Newman-Unti-Tamburino) black hole in four dimensional \emph{Lorentzian geometry}. We observe that these thermodynamic products ... More
Can we predict the failure point of a loaded composite material?Sep 07 2010As a model of composite material, the fiber bundle model has been chosen -where a bundle of fibers is subjected to external load and fibers have distributed thresholds. For different loading conditions, such a system shows few precursors which indicate ... More
Three axis vector atomic magnetometer utilizing polarimetric techniqueMar 28 2016The three axis magnetic field measurement based on the interaction of a single elliptically polarized light beam with an atomic system is described. The magnetic field direction dependent atomic responses are extracted by the polarimetric detection in ... More
Regular sequences of power sums and complete symmetric polynomialsOct 31 2011Mar 25 2013In this article, we carry out the investigation for regular sequences of symmetric polynomials in the polynomial ring in three and four variable. Any two power sum element in $\mathbb{C}[x_1,x_2,...,x_n]$ for $n \geq 3$ always form a regular sequence ... More
Circular Orbits in the Taub-NUT and mass-less Taub-NUT Space-timeMay 20 2016In this work we study the equatorial causal geodesics of the Taub-NUT(TN) space-time in comparison with \emph{mass-less} TN space-time. We emphasized both on the null circular geodesics and time-like circular geodesics. From the effective potential diagram ... More
String Black Holes as Particle Accelerators to Arbitrarily High EnergyOct 30 2013Mar 25 2014We show that an extremal Gibbons-Maeda-Garfinkle-Horowitz-Strominger black hole may act as a particle accelerator with arbitrarily high energy when two uncharged particles falling freely from rest to infinity on the near horizon. We show that the center ... More
Logarithmic Corrections in Black Hole Entropy Product FormulaMar 24 2016Jun 01 2016It has been shown by explicit and exact calculation that whenever we have taken the \emph{effects of stable thermal fluctuations} the entropy product formula should \emph{not be mass-independent} nor \emph{does it quantized}. It has been examined by giving ... More
Tidal Charged Black Holes as Particle Accelerators to Arbitrarily High EnergyDec 28 2014We show that Randall Sundrum tidal charged spherically symmetric vacuum brane black holes could be act as a particle accelerator with ultrahigh center-of-mass energy in the limiting case of \emph{ maximal black hole tidal charge}. For non-extremal Randall ... More
Hofstadter butterfly in the Falicov-Kimball model on some finite 2D latticesJun 20 2016Spinless, interacting electrons on a finite size triangular lattice moving in an extremely strong perpendicular magnetic field are studied and compared with the results on a square lattice. Using a Falicov-Kimball model, the effects of the magnetic field, ... More
Random trading market: Drawbacks and a realistic modificationMar 14 2005We point out some major drawbacks in random trading market models and propose a realistic modification which overcomes such drawbacks through `sensible trading'. We apply such trading policy in different situations: a) Agents with zero saving factor b) ... More
High Speed, Low Power Current Comparators with HysteresisMar 14 2012This paper, presents a novel idea for analog current comparison which compares input signal current and reference currents with high speed, low power and well controlled hysteresis. Proposed circuit is based on current mirror and voltage latching techniques ... More
Nonlinear evolution of electron shear flow instabilities in the presence of an external guide magnetic fieldAug 08 2016The dissipation mechanism by which the magnetic field reconnects in the presence of an external (guide) magnetic field in the direction of the main current is not well understood. In thin electron current sheets (ECS) (thickness ~ an electron inertial ... More
Effect of guide field on three dimensional electron shear flow instabilities in collisionless magnetic reconnectionNov 12 2014Apr 06 2015We examine the effect of an external guide field and current sheet thickness on the growth rates and nature of three dimensional unstable modes of an electron current sheet driven by electron shear flow. The growth rate of the fastest growing mode drops ... More
Area products for ${\cal H}^{\pm}$ in AdS spaceJun 20 2016Oct 12 2016We derive the thermodynamic products particularly area (or entropy) products of ${\cal H}^{\pm}$ for certain class of black holes in AdS space. We show by explicit and exact calculations that more complicated function of event horizon area and Cauchy ... More
Area (or Entropy) Bound of Horizons for Hořava Lifshitz Black HoleMay 04 2016Oct 13 2016We speculate various thermodynamic features of the inner horizon (${\mathcal H}^{-}$) and outer horizon (${\mathcal H}^{+}$) in the background of Ho\v{r}ava Lifshitz black hole (BH). We compute particularly \emph{area sum, area minus and area division} ... More
Charged Dilation Black Holes as Particle AcceleratorsJul 03 2014Oct 10 2014We examine the possibility of arbitrarily high energy in the Center-of-mass(CM) frame of colliding neutral particles in the vicinity of the horizon of a charged dilation black hole(BH). We show that it is possible to achieve the infinite energy in the ... More
Stability analysis and quasinormal modes of Reissner Nordstrøm Space-time via Lyapunov exponentMay 25 2012Jun 15 2016We explicitly derive the proper time $(\tau)$ principal Lyapunov exponent ($\lambda_{p}$) and coordinate time ($t$) principal Lyapunov exponent ($\lambda_{c}$) for Reissner Nordstr{\o}m (RN) black hole (BH) . We also compute their ratio. For RN space-time, ... More
A Model for Quantum Stochastic Absorption in Absorbing Disordered MediaJan 05 2004Wave propagation in coherently absorbing disordered media is generally modeled by adding a complex part to the real part of the potential. In such a case, it is already understood that the complex potential plays a duel role; it acts as an absorber as ... More
Transport and localization of waves in one-dimensional disordered media: Random phase approximation and beyondMar 31 1997We report a systematic and detailed numerical study of statistics of the reflection coefficient $(|R(L)|^2)$ and its associated phase ($\theta$) for a plane wave reflected from a one-dimensional (1D) disordered medium beyond the random phase approximation ... More
Entropy Product Formula for Gravitational InstantonSep 23 2016We investigate the entropy product formula for various gravitational instantons. We speculate that due to the mass-independent characteristics of the said instatons they are \emph{universal} as well as they are \emph{quantized}. For isolated Euclidean ... More
Circular Orbits in the Taub-NUT and mass-less Taub-NUT Space-timeMay 20 2016Oct 26 2016In this work we study the equatorial causal geodesics of the Taub-NUT(TN) space-time in comparison with \emph{mass-less} TN space-time. We emphasized both on the null circular geodesics and time-like circular geodesics. From the effective potential diagram ... More
Thermodynamic Product Relations for Generalized Regular Black HoleMar 24 2016Jul 03 2016We derive thermodynamic product relations for four-parametric regular black hole (BH) solutions of the Einstein equations coupled with a non-linear electrodynamics source. The four parameters can be described by the mass ($m$), charge ($q$), dipole moment ... More
Surface Area Products for Kerr-Taub-NUT Space-timeAug 13 2014Aug 08 2016We examine properties of the inner and outer horizon thermodynamics of Taub-NUT (Newman-Unti-Tamburino) and Kerr-Taub-NUT (KTN) black hole (BH) in four dimensional \emph{Lorentzian geometry}. We compare and contrasted these properties with the properties ... More
Nonequilibrium fluctuation theorems in the presence of a time-reversal symmetry-breaking field and nonconservative forcesNov 19 2009Feb 22 2010We study nonequilibrium fluctuation theorems in the presence of a time-reversal symmetry-breaking field and nonconservative forces, in a stochastic as well as a deterministic set up. We consider a system and a heat bath, called the combined system, and ... More
Thermodynamic Volume Product in Spherically Symmetric and Axisymmetric SpacetimeNov 14 2016In this Letter, we compute particularly thermodynamic \emph{volume product, volume sum, volume minus and volume division} for wide variety of spherically symmetric spacetime and axisymmetric spacetime in the frame work of \emph{extended phase space}. ... More
Macroscopic magnetic field generated in laser atom interactionDec 16 2016Jan 19 2018We observe shift in the zero magnetic field resonance as the handedness of resonantly interacting circularly polarized light is changed. The characteristic of the shift resembles with the Zeeman light shift that arises due to interaction of non-resonant ... More
Physics Models of EarthquakeJan 10 2007Since long back, scientists have been putting enormous effort to understand earthquake dynamics -the goal is to develop a successful prediction scheme which can provide reliable alarm that an earthquake is imminent. Model studies sometimes help to understand ... More
Efficient cache oblivious algorithms for randomized divide-and-conquer on the multicore modelApr 29 2012May 27 2012In this paper we present randomized algorithms for sorting and convex hull that achieves optimal performance (for speed-up and cache misses) on the multicore model with private cache model. Our algorithms are cache oblivious and generalize the randomized ... More
Associated 21-cm HI absorption towards the radio galaxy 3C452 (J2245+3941)May 17 2006We report the detection of 21-cm HI absorption towards the core of the Fanaroff-Riley II radio galaxy 3C452 (J2245+3941). The absorption profile is well resolved into three components; the strongest and narrowest component being coincident with the velocity ... More
Modelling an Aircraft Landing System in Event-B (Full Report)Jul 03 2014The failure of hardware or software in a critical system can lead to loss of lives. The design errors can be main source of the failures that can be introduced during system development process. Formal techniques are an alternative approach to verify ... More
Flat and One-Variable Clauses: Complexity of Verifying Cryptographic Protocols with Single Blind CopyingNov 03 2005Cryptographic protocols with single blind copying were defined and modeled by Comon and Cortier using the new class $\mathcal C$ of first order clauses. They showed its satisfiability problem to be in 3-DEXPTIME. We improve this result by showing that ... More
Alkalized Borazine: A Simple Recipe to Design Superalkali SpeciesJun 08 2016We propose a simple yet effective route to the design of superalkalis, by successive alkali metal substitution in borazine (B3N3H6). Using Li atoms, our density functional calculations demonstrate that the vertical ionization energy (VIE) of B3N3H6-xLix ... More
Global mibility and handover management for heterogeneous network in VANETOct 18 2013Now a days Vehicular Ad hoc Network is an emerging technology. Mobility management is one of the most challenging research issues for Vehicular Ad hoc Network to support variety of intelligent transportation system applications. Vehicular Ad hoc Networks ... More
Note on vanishing power sums of roots of unityMar 25 2015Mar 03 2016For a given positive integers $m$ and $\ell$, we give a complete list of positive integers $n$ for which their exist $m$th roots of unity $x_1,\dots,x_n \in \mathbb{C}$ such that $x_1^{\ell} + \cdots + x_n^{\ell}=0$. This extends the earlier result of ... More
Competition between Alkalide Characteristics and Nonlinear Optical Properties in OLi3-M-Li3O (M=Li, Na and K) ComplexesApr 24 2016Alkalides possess enhanced nonlinear optical (NLO) responses due to localization of excess electrons on alkali metals. We have proposed a new class of alkalides by sandwiching alkali atoms (M) between two Li3O superalkali clusters at MP2/6-311++G(d,p) ... More
Resolution and regularity of cover ideals of certain multipartite graphsSep 15 2017Let $G$ be a finite simple graph on $n$ vertices. Let $J_G \subset K[x_1, \ldots, x_n]$ be the cover ideal of $G$. In this article, we obtain the graded minimal free resolution and the Castelnuovo-Mumford regularity of $J_G^s$ for all $s \geq 1$ for certain ... More
Apparent strength conceals instability in a model for the collapse of historical statesJul 10 2013An explanation for the political processes leading to the sudden collapse of empires and states would be useful for understanding both historical and contemporary political events. We seek a general description of state collapse spanning eras and cultures, ... More
Techniques and Applications of Computation SlicingMar 15 2003Writing correct distributed programs is hard. In spite of extensive testing and debugging, software faults persist even in commercial grade software. Many distributed systems, especially those employed in safety-critical environments, should be able to ... More
Quillen-Suslin theory for a structure theorem for the Elementary Symplectic GroupMar 09 2012Mar 25 2013A new set of elementary symplectic elements is described, It is shown that these also generate the elementary symplectic group {\rm ESp}$_{2n}(R)$. These generators are more symmetrical than the usual ones, and are useful to study the action of the elementary ... More
Designing New Electrolytes for Lithium Ion Batteries Using Superhalogen AnionsApr 01 2016The electrolytes used in Lithium Ion Batteries (LIBs) such as LiBF4, LiPF6 etc. are Li-salts of some complex anions, BF4-, PF6- etc. The investigation shows that the vertical detachment energy (VDE) of these anions exceeds to that of halogen, and therefore ... More
Electron scale nested quadrupole Hall field in Cluster observations of magnetic reconnectionMay 23 2014This Letter presents the first evidence of a new and unique feature of spontaneous reconnection at multiple sites in electron current sheet, viz. nested quadrupole structure of Hall field at electron scales, in Cluster observations. The new nested quadrupole ... More
A family of well-behaved Karmarkar spacetime describing interior of relativistic starsJul 10 2016Aug 19 2016We are presenting a family of new exact solutions for relativistic anisotropic stellar objects by considering four dimensional spacetime embedded in five dimensional Pseudo Euclidean space known as Class I solutions. These solutions are well-behaved in ... More
Commuting conjugates of finite-order mapping classesJan 31 2019Let $\text{Mod}(S_g)$ be the mapping class group of the closed orientable surface $S_g$ of genus $g\geq 2$. In this paper, we derive necessary and sufficient conditions for two finite-order mapping classes to have commuting conjugates in $\text{Mod}(S_g)$. ... More
Magnetic Order Beyond RKKY in the Classical Kondo LatticeOct 01 2008Jan 23 2009We study the Kondo lattice model of band electrons coupled to classical spins, in three dimensions, using a combination of variational calculation and Monte Carlo. We use the weak coupling `RKKY' window and the strong coupling regime as benchmarks, but ... More
Convergence of maxgeneralized mean-mingeneralized mean powers of intuitionistic fuzzy matricesJul 01 2014Intuitionistic fuzzy relations on finite universes can be represent by intuitionistic fuzzy matrices and the limiting behavior of the power matrices depends on the algebraic operation employed on the matrices. In this paper, the power of intuitionistic ... More
Quantum Mechanics Of ConsciousnessJul 28 2009Jul 29 2009A phenomenological approach using the states of spin-like observables is developed to understand the nature of consciousness and the totality of experience. The three states of consciousness are taken to form the triplet of eigenstates of a spin-one entity ... More
ISCO and Principal Null Congruences in Extremal Kerr SpacetimeOct 07 2012The effective potential in universal like coordinates$(U, V, \theta, \phi)$, which are smooth across the event horizon is derived and investigated the ISCO(Innermost Stable Circular Orbits) explicitly in these coordinates for extremal Kerr spacetime. ... More
Residence Time Distribution of Sand Grains in the 1-Dimensional Abelian Sandpile ModelMar 31 2004We study the probability distribution of residence time, $T$, of the sand grains in the one dimensional abelian sandpile model on a lattice of $L$ sites, for $T<<L^2$ and $T>>L^2$. The distribution function decays as $\exp(-\frac{K_LT}{L^2})$. We numerically ... More
ISCO, Lyapunov exponent and Kolmogorov-Sinai entropy for Kerr-Newman Black holeDec 23 2012We compute the principal Lyapunov exponent and Kolmogorov-Sinai(KS) entropy for Kerr-Newman black hole space-times and investigate the stability and instability of the equatorial circular geodesics via these exponents. We also show that the principal ... More
Bianchi Type-$V$ cosmology in $f(R,T)$ gravity with $Λ(T)$Mar 12 2013Jul 14 2014A new class of cosmological models in $f(R, T)$ modified theories of gravity proposed by Harko et al. (2011), where the gravitational Lagrangian is given by an arbitrary function of Ricci scalar $R$ and the trace of the stress-energy tensor $T$, have ... More
A Noninvasive Magnetic Stimulator Utilizing Secondary Ferrite Cores and Resonant Structures for Field EnhancementSep 27 2016In this paper, secondary ferrite cores and resonant structures have been used for field enhancement. The tissue was placed between the double square source coil and the secondary ferrite core. Resonant coils were added which aided in modulating the electric ... More
A Hybrid Density Functional Study of Armchair Si and Ge NanotubesJul 28 2005First principles calculations based on hybrid density functional theory have been used to study the electronic and geometric properties of armchair silicon and germanium nanotubes ranging from A (3, 3) through A (9, 9). The approach used is the finite ... More
Sampling rare fluctuations of height in the Oslo ricepile modelAug 06 2006We have studied large deviations of the height of the pile from its mean value in the Oslo ricepile model. We sampled these very rare events with probabilities of order $10^{-100}$ by Monte Carlo simulations using importance sampling. These simulations ... More
Bianchi Type III String Cosmological Models with Time Dependent Bulk ViscosityNov 03 2006Jan 01 2007Bianchi type III string cosmological models with bulk viscous fluid for massive string are investigated. To get the determinate model of the universe, we have assumed that the coefficient of bulk viscosity ($\xi$) is inversely proportional to the expansion ... More
Some Bianchi Type I Viscous Fluid Cosmological Models with a Variable Cosmological ConstantJul 29 2004Some Bianchi type I viscous fluid cosmological models with a variable cosmological constant are investigated in which the expansion is considered only in two direction i.e. one of the Hubble parameter $(H_{1} = \frac{A_{4}}{A})$ is zero. The viscosity ... More
Viscous Dark Energy and Phantom Field in An Anisotropic UniverseJan 16 2014In this paper we have investigated the general form of viscous and non-viscous dark energy equation of state (EoS) parameter in the scope of anisotropic Bianchi type I space-time. We show that the presence of bulk viscosity causes transition of $\omega^{de}$ ... More
Psychophysical Interpretation of Quantum theoryJun 25 2012Dec 16 2012It is shown that the formalism of quantum theory naturally incorporates the psychophysical parallelism and thereby interprets itself, if the subjective aspects are taken as equal partners alongside the objective aspects as determinants of Reality as a ... More
The Iron Project and the RmaX ProjectOct 23 2003Ongoing activities under an international collaboration of atomic physicists and astrophysicists under the Iron Project and the RmaX Project, with applications to X-ray astronomy, are briefly described.
Optimal Monte Carlo Estimation of Belief Network InferenceFeb 13 2013We present two Monte Carlo sampling algorithms for probabilistic inference that guarantee polynomial-time convergence for a larger class of network than current sampling algorithms provide. These new methods are variants of the known likelihood weighting ... More
Study of Geodesics and the Frame-dragging effect in a Rotating Traversable WormholeMar 31 2016The complete equatorial causal geodesic structure of a rotating traversable wormhole is analyzed and it has been shown that the ISCO (Innermost Stable Circular Orbit) coincides at the throat of the wormhole for the retrograde rotation. By studying the ... More
Are All Probabilities Fundamentally Quantum Mechanical?May 28 2011The subjective and the objective aspects of probabilities are incorporated in a simple duality axiom inspired by observer participation in quantum theory. Transcending the classical notion of probabilities, it is proposed and demonstrated that all probabilities ... More
Are Quantum States Subjective?Feb 22 2012The subjective nature of the quantum states is brought out and it is argued that the objective state assignment is subsequent to the subjective state of the observer regarding his state of knowledge about the system. The collapse postulate is examined ... More
Bulk Viscous Solutions to the Field Equations and the Deceleration Parameter-RevisitedJul 04 2002We utilise a form for the Hubble parameter to generate a number of solutions to the Einstein field equations with variable cosmological constant and variable gravitational constant in the presence of a bulk viscous fluid. The Hubble law utilised yields ... More
Lyapunov Exponent and Charged Myers Perry SpacetimesFeb 11 2013Jun 10 2013We compute the proper time Lyapunov exponent for charged Myers Perry black hole spacetime and investigate the instability of the equatorial circular geodesics (both timelike and null) via this exponent. We also show that for more than four spacetime dimensions ... More
Circular Orbits in Extremal Reissner Nordstrom SpacetimesJan 03 2010Apr 01 2010Circular null geodesic orbits, in extremal Reissner-Nordstrom spacetimes, are examined with regard to their stability, and compared with similar orbits in the near-extremal situation. Extremization of the effective potential for null circular orbits shows ... More
From chaos to disorder: Statistics of the eigenfunctions of microwave cavitiesJan 14 2002May 29 2002We study the statistics of the experimental eigenfunctions of chaotic and disordered microwave billiards in terms of the moments of their spatial distributions, such as the Inverse Participation Ratio (IPR) and density-density auto-correlation. A path ... More
Thermodynamic Theory of Phase Transitions in Driven Lattice GasesJul 28 2011Nov 29 2011We formulate an approximate thermodynamic theory of the phase transition in driven lattice gases with attractive nearest-neighbor interactions. We construct the van der Waals equation of state for a driven system where a nonequilibrium chemical potential ... More