Results for "Giri Gopalan"

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Admissibility of a posterior predictive decision ruleJul 22 2015Jun 25 2016Recent decades have seen an interest in prediction problems for which Bayesian methodology has been extremely useful. Sampling from or approximating the posterior predictive distribution in a Bayesian model allows one to make inferential statements about ... More
Quantifying the information of the prior and likelihood in parametric Bayesian modelingNov 04 2015Jun 25 2016I suggest using a pair of metrics to quantify the information of the prior and likelihood functions within a parametric Bayesian model, one of which is closely related to the reference priors of Berger and Bernardo (Bernardo 1979, Berger and Bernardo ... More
Classifying X-ray Binaries: A Probabilistic ApproachJul 13 2015Aug 17 2018In X-ray binary star systems consisting of a compact object that accretes material from an orbiting secondary star, there is no straightforward means to decide if the compact object is a black hole or a neutron star. To assist this classification, we ... More
FastGP: An R Package for Gaussian ProcessesJul 22 2015Despite their promise and ubiquity, Gaussian processes (GPs) can be difficult to use in practice due to the computational impediments of fitting and sampling from them. Here we discuss a short R package for efficient multivariate normal functions which ... More
Classifying X-ray Binaries: A Probabilistic ApproachJul 13 2015In X-ray binary star systems consisting of a compact object that accretes material from an orbiting secondary star, there is no straightforward means to decide if the compact object is a black hole or a neutron star. To assist this process we develop ... More
Thompson Sampling for Online Learning with Linear ExpertsNov 03 2013In this note, we present a version of the Thompson sampling algorithm for the problem of online linear generalization with full information (i.e., the experts setting), studied by Kalai and Vempala, 2005. The algorithm uses a Gaussian prior and time-varying ... More
A Seamless Integration of Association Rule Mining with Database SystemsJun 28 2001The need for Knowledge and Data Discovery Management Systems (KDDMS) that support ad hoc data mining queries has been long recognized. A significant amount of research has gone into building tightly coupled systems that integrate association rule mining ... More
PAC Battling Bandits in the Plackett-Luce ModelAug 12 2018Oct 05 2018We introduce the probably approximately correct (PAC) {Battling-Bandit} problem with the Plackett-Luce (PL) subset choice model---an online learning framework where at each trial the learner chooses a subset of $k$ arms from a fixed set of $n$ arms, and ... More
A Simplified Suspension Calculus and its Relationship to Other Explicit Substitution CalculiFeb 26 2007This paper concerns the explicit treatment of substitutions in the lambda calculus. One of its contributions is the simplification and rationalization of the suspension calculus that embodies such a treatment. The earlier version of this calculus provides ... More
From PAC to Instance-Optimal Sample Complexity in the Plackett-Luce ModelMar 01 2019We consider PAC learning for identifying a good item from subset-wise samples in \pl\, probability models, with instance-dependent sample complexity performance. For the setting where subsets of a fixed size can be tested and top-ranked feedback is made ... More
Proceedings Sixth International Workshop on Logical Frameworks and Meta-languages: Theory and PracticeOct 31 2011This volume constitutes the proceedings of LFMTP 2011, the Sixth International Workshop on Logical Frameworks and Meta-languages: Theory and Practice. The LFMTP workshop series brings together designers, implementors, and practitioners to discuss varied ... More
Towards a Logic for Reasoning About LF SpecificationsJun 26 2018We describe the development of a logic for reasoning about specifications in the Edinburgh Logical Framework (LF). In this logic, typing judgments in LF serve as atomic formulas, and quantification is permitted over contexts and terms that might appear ... More
Active Ranking with Subset-wise PreferencesOct 23 2018Mar 01 2019We consider the problem of probably approximately correct (PAC) ranking $n$ items by adaptively eliciting subset-wise preference feedback. At each round, the learner chooses a subset of $k$ items and observes stochastic feedback indicating preference ... More
A Lambda Prolog Based Animation of Twelf SpecificationsJul 06 2014Specifications in the Twelf system are based on a logic programming interpretation of the Edinburgh Logical Framework or LF. We consider an approach to animating such specifications using a Lambda Prolog implementation. This approach is based on a lossy ... More
Modeling pre-biotic self-organization: The chemical dynamics of autocatalytic networksMar 29 2013In this thesis we present a mathematical model describing the population dynamics of molecules in an artificial chemistry where large molecules can be produced by successive ligation of pairs of smaller molecules. The chemistry contains a large number ... More
A Higher-Order Abstract Syntax Approach to Verified Transformations on Functional ProgramsSep 12 2015Jan 23 2016We describe an approach to the verified implementation of transformations on functional programs that exploits the higher-order representation of syntax. In this approach, transformations are specified using the logic of hereditary Harrop formulas. On ... More
Thompson Sampling for Learning Parameterized Markov Decision ProcessesJun 29 2014Mar 31 2015We consider reinforcement learning in parameterized Markov Decision Processes (MDPs), where the parameterization may induce correlation across transition probabilities or rewards. Consequently, observing a particular state transition might yield useful ... More
Short average distribution of a prime counting function over families of elliptic curvesSep 27 2016Let $E$ be an elliptic curve defined over $\mathbb{Q}$ and let $N$ be a positive integer. Now, $M_E(N)$ counts the number of primes $p$ such that the group $E_p(\mathbb{F}_p)$ is of order $N$. In an earlier joint work with Balasubramanian, we showed that ... More
New Symmetries in Crystals and Handed StructuresJul 21 2010Feb 04 2011For over a century, the structure of materials has been described by a combination of rotations, rotation-inversions and translational symmetries. By recognizing the reversal of static structural rotations between clockwise and counterclockwise directions ... More
The Antisymmetry of DistortionsJun 01 2015Distortions are ubiquitous in nature. Under perturbations such as stresses, fields, or other changes, a physical system reconfigures by following a path from one state to another; this path, often a collection of atomic trajectories, describes a distortion. ... More
A Hierarchical Spatio-Temporal Statistical Model Motivated by GlaciologyNov 20 2018Jun 04 2019In this paper, we extend and analyze a Bayesian hierarchical spatio-temporal model for physical systems. A novelty is to model the discrepancy between the output of a computer simulator for a physical process and the actual process values with a multivariate ... More
Application of the Trend Filtering Algorithm for Photometric Time Series DataMar 18 2016Detecting transient light curves (e.g., transiting planets) requires high precision data, and thus it is important to effectively filter systematic trends affecting ground based wide field surveys. We apply an implementation of the Trend Filtering Algorithm ... More
A Hierarchical Spatio-Temporal Statistical Model for Physical SystemsNov 20 2018In this paper, we extend and analyze a Bayesian hierarchical spatio-temporal model for physical systems. A novelty is to model the discrepancy between the output of a computer simulator for a physical process and the actual process values with a multivariate ... More
Nanoscale piezoelectric response across a single antiparallel ferroelectric domain wallMar 09 2005Surprising asymmetry in the local electromechanical response across a single antiparallel ferroelectric domain wall is reported. Piezoelectric force microscopy is used to investigate both the in-plane and out-of- plane electromechanical signals around ... More
A Topological Approach to Creating any Pulli Kolam, an Artform from Southern IndiaMar 07 2015May 31 2015Pulli kolam is a ubiquitous art form in south India. It involves drawing a line looped around a collection of dots (pullis) place on a plane such that three mandatory rules are followed: all line orbits should be closed, all dots are encircled and no ... More
On Kernelized Multi-armed BanditsApr 03 2017May 17 2017We consider the stochastic bandit problem with a continuous set of arms, with the expected reward function over the arms assumed to be fixed but unknown. We provide two new Gaussian process-based algorithms for continuous bandit optimization-Improved ... More
Limiting Network Size within Finite Bounds for OptimizationMar 07 2019Largest theoretical contribution to Neural Networks comes from VC Dimension which characterizes the sample complexity of classification model in a probabilistic view and are widely used to study the generalization error. So far in the literature the VC ... More
Bayesian Optimization under Heavy-tailed PayoffsSep 16 2019We consider black box optimization of an unknown function in the nonparametric Gaussian process setting when the noise in the observed function values can be heavy tailed. This is in contrast to existing literature that typically assumes sub-Gaussian ... More
On the properties of Ascent and Descent of Composition operator on Orlicz spacesJun 14 2016Here, the composition operators on Orlicz spaces with finite ascent and descent as well as infinite ascent and descent are characterized.
Quantization of neutron in Earth's gravityAug 20 2007Aug 22 2007Gravity is the weakest of all four known forces in the universe. Quantum states of an elementary particle due to such a weak field is certainly very shallow and would therefore be an experimental challenge to detect. Recently an experimental attempt was ... More
Asymptotic quasinormal modes of a noncommutative geometry inspired Schwarzschild black holeApr 25 2006Feb 01 2007We study the asymptotic quasi-normal modes for the scalar perturbation of the non-commutative geometry inspired Schwarzschild black hole in (3+1) dimensions. We have considered $M\geq M_0$, which effectively correspond to a single horizon Schwarzschild ... More
Atom capture by nanotube and scaling anomalyJun 20 2007Nov 19 2007The existence of bound state of the polarizable neutral atom in the inverse square potential created by the electric field of single walled charged carbon nanotube (SWNT) is shown to be theoretically possible. The consideration of inequivalent boundary ... More
Further properties of frequentist confidence intervals in regression that utilize uncertain prior informationNov 09 2011Apr 02 2012Consider a linear regression model with n-dimensional response vector, regression parameter \beta = (\beta_1, ..., \beta_p) and independent and identically N(0, \sigma^2) distributed errors. Suppose that the parameter of interest is \theta = a^T \beta ... More
Simultaneous confidence intervals for the population cell means, for two-by-two factorial data, that utilize uncertain prior informationDec 09 2008Apr 30 2012Consider a two-by-two factorial experiment with more than 1 replicate. Suppose that we have uncertain prior information that the two-factor interaction is zero. We describe new simultaneous frequentist confidence intervals for the 4 population cell means, ... More
Does changing the pulling direction give better insight into biomolecules?Jan 27 2007Single molecule manipulation techniques reveal that the mechanical resistance of a protein depends on the direction of the applied force. Using a lattice model of polymers, we show that changing the pulling direction leads to different phase diagrams. ... More
Supersymmetric quantum mechanical generalized MIC-Kepler systemJul 10 2006Sep 20 2007We construct supersymmetric (SUSY) generalized MIC-Kepler system and show that the systems with half integral Dirac quantization condition \mu= \pm{1/2}, \pm{3/2}, \pm{5/2},..... belong to a SUSY family (hierarchy of Hamiltonian) with same spectrum between ... More
Observational signatures from horizonless black shells imitating rotating black holesDec 01 2017Jul 13 2018In arXiv:1705.10172 it was proposed that string theory replaces Schwarzschild black holes with horizonless thin shells with an AdS interior. In this paper we extend the analysis to slowly rotating black holes, solving the Israel-Lanczos-Sen junction conditions ... More
Effects of Eye-phase in DNA unzippingApr 24 2007The onset of an "eye-phase" and its role during the DNA unzipping is studied when a force is applied to the interior of the chain. The directionality of the hydrogen bond introduced here shows oscillations in force-extension curve similar to a "saw-tooth" ... More
The origin of large molecules in primordial autocatalytic reaction networksOct 17 2011Large molecules such as proteins and nucleic acids are crucial for life, yet their primordial origin remains a major puzzle. The production of large molecules, as we know it today, requires good catalysts, and the only good catalysts we know that can ... More
Mean-Value of Product of Shifted Multiplicative Functions and Average Number of Points on Elliptic CurvesAug 14 2014Sep 03 2014In this paper, we consider the mean value of the product of two real valued multiplicative functions with shifted arguments. The functions $F$ and $G$ under consideration are close to two nicely behaved functions $A$ and $B$, such that the average value ... More
On a class of optimally low-dissipation low-dispersion high order implicit Runge-Kutta schemesApr 21 2018In this work we derive a class of optimally low-dissipation low-dispersion implicit Runge-Kutta (R-K) schemes. The schemes obtained by minimizing amplification and phase error suggest little dissipation and comparatively lesser dispersive nature. Emphasis ... More
Large-Sample Confidence Intervals for the Treatment Difference in a Two-Period Crossover Trial, Utilizing Prior InformationJul 10 2008Oct 15 2008Consider a two-treatment, two-period crossover trial, with responses that are continuous random variables. We find a large-sample frequentist 1-alpha confidence interval for the treatment difference that utilizes the uncertain prior information that there ... More
Confidence intervals in regression utilizing prior informationNov 20 2007Mar 25 2009We consider a linear regression model with regression parameter beta=(beta_1,...,beta_p) and independent and identically N(0,sigma^2) distributed errors. Suppose that the parameter of interest is theta = a^T beta where a is a specified vector. Define ... More
Non-hermitian models in higher dimensionsNov 17 2008It is know that PT-symmetric models have real spectra provided the symmetry is not spontaneously broken. Even pseudo-hermitian models have real spectra, which enlarge the the class of non-hermitian models possessing real spectra. We however consider non-hermitian ... More
Lower bound of minimal time evolution in quantum mechanicsJun 25 2007Jan 14 2008We show that the total time of evolution from the initial quantum state to final quantum state and then back to the initial state, i.e., making a round trip along the great circle over S^2, must have a lower bound in quantum mechanics, if the difference ... More
Conformal anomaly in non-hermitian quantum mechanicsMay 19 2008A model of an electron and a Dirac monopole interacting through an axially symmetric non-hermitian but \mathcal{PT}-symmetric potential is discussed in detail. The intriguing localization of the wave-packet as a result of the anomalous breaking of the ... More
Inequivalent quantization in the field of a ferromagnetic wireAug 22 2007Nov 07 2007We argue that it is possible to bind neutral atom (NA) to the ferromagnetic wire (FW) by inequivalent quantization of the Hamiltonian. We follow the well known von Neumann's method of self-adjoint extensions (SAE) to get this inequivalent quantization, ... More
Dipole binding in a cosmic string background due to quantum anomaliesApr 22 2007Jun 19 2007We propose quantum dynamics for the dipole moving in cosmic string background and show that the classical scale symmetry of a particle moving in cosmic string background is still restored even in the presence of dipole moment of the particle. However, ... More
Convergence of the cell average technique for Smoluchowski coagulation equationAug 02 2012We present the convergence analysis of the cell average technique, introduced in [12], to solve the nonlinear continuous Smoluchowski coagulation equation. It is shown that the technique is second order accurate on uniform grids and first order accurate ... More
Phase error analysis of implicit Runge-Kutta methods: Introducing new classes of minimal dissipation low dispersion high order schemesApr 21 2018Jun 23 2019In current research, we analyse dissipation and dispersion characteristics of most accurate two and three stage Gauss-Legendre implicit Runge-Kutta (R-K) methods. These methods, known for their $A$-stability and immense accuracy, are observed to carry ... More
Spin-ladders with spin gaps: A description of a class of cupratesDec 06 1993We investigate the magnetic properties of the Cu-O planes in stoichiometric Sr$_{n-1}$Cu$_{n+1}$O$_{2n}$ (n=3,5,7,...) which consist of CuO double chains periodically intergrown within the CuO$_2$ planes. The double chains break up the two-dimensional ... More
Pseudorandomness via the discrete Fourier transformJun 14 2015Nov 18 2015We present a new approach to constructing unconditional pseudorandom generators against classes of functions that involve computing a linear function of the inputs. We give an explicit construction of a pseudorandom generator that fools the discrete Fourier ... More
A two-level logic approach to reasoning about computationsNov 16 2009Sep 01 2010Relational descriptions have been used in formalizing diverse computational notions, including, for example, operational semantics, typing, and acceptance by non-deterministic machines. We therefore propose a (restricted) logical theory over relations ... More
Collaborative Learning of Stochastic Bandits over a Social NetworkFeb 29 2016Jul 11 2016We consider a collaborative online learning paradigm, wherein a group of agents connected through a social network are engaged in playing a stochastic multi-armed bandit game. Each time an agent takes an action, the corresponding reward is instantaneously ... More
Wireless Scheduling with Partial Channel State Information: Large Deviations and OptimalityMay 24 2014Mar 31 2015We consider a server serving a time-slotted queued system of multiple packet-based flows, with exogenous packet arrivals and time-varying service rates. At each time, the server can observe instantaneous service rates for only a subset of flows (from ... More
Thompson Sampling for Complex Bandit ProblemsNov 03 2013We consider stochastic multi-armed bandit problems with complex actions over a set of basic arms, where the decision maker plays a complex action rather than a basic arm in each round. The reward of the complex action is some function of the basic arms' ... More
Low-rank Bandits with Latent MixturesSep 06 2016We study the task of maximizing rewards from recommending items (actions) to users sequentially interacting with a recommender system. Users are modeled as latent mixtures of C many representative user classes, where each class specifies a mean reward ... More
Locally Testable Codes and Cayley GraphsAug 23 2013We give two new characterizations of ($\F_2$-linear) locally testable error-correcting codes in terms of Cayley graphs over $\F_2^h$: \begin{enumerate} \item A locally testable code is equivalent to a Cayley graph over $\F_2^h$ whose set of generators ... More
Combining generic judgments with recursive definitionsFeb 06 2008Apr 14 2008Many semantical aspects of programming languages, such as their operational semantics and their type assignment calculi, are specified by describing appropriate proof systems. Recent research has identified two proof-theoretic features that allow direct, ... More
Polynomial-Time Approximation Schemes for Knapsack and Related Counting Problems using Branching ProgramsAug 18 2010We give a deterministic, polynomial-time algorithm for approximately counting the number of {0,1}-solutions to any instance of the knapsack problem. On an instance of length n with total weight W and accuracy parameter eps, our algorithm produces a (1 ... More
Localization at threshold in noncommutative spaceJan 02 2008Feb 07 2008The ground state energy of a scale symmetric system usually does not possess any lower bound, thus making the system quantum mechanically unstable. Self-adjointness and renormalization techniques usually provide the system a scale and thus making the ... More
Self-Adjointness of Generalized MIC-Kepler SystemMar 29 2006Sep 20 2007We have studied the self-adjointness of generalized MIC-Kepler Hamiltonian, obtained from the formally self-adjoint generalized MIC-Kepler Hamiltonian. We have shown that for \tilde l=0, the system admits a 1-parameter family of self-adjoint extensions ... More
Generalized Solutions for Quantum Mechanical Oscillator on Kähler ConifoldMar 24 2006Jun 05 2006We study the possible generalized boundary conditions and the corresponding solutions for the quantum mechanical oscillator model on K\"{a}hler conifold. We perform it by self-adjoint extension of the the initial domain of the effective radial Hamiltonian. ... More
Quantum oscillator on complex projective space (Lobachewski space) in constant magnetic field and the issue of generic boundary conditionsMay 16 2006Feb 05 2007We perform a 1-parameter family of self-adjoint extensions characterized by the parameter $\omega_0$. This allows us to get generic boundary conditions for the quantum oscillator on $N$ dimensional complex projective space($\mathbb{C}P^N$) and on its ... More
On Additive Representation FunctionsJul 31 2012May 08 2014Let $\A=\{a_1<a_2<a_3.....<a_n<...\}$ be an infinite sequence of integers and let $R_2(n)=|\{(i,j):\ \ a_i+a_j=n;\ \ a_i,a_j\in \A;\ \ i\le j\}|$. We define $S_k=\s_{l=1}^k(R_2(2l)-R_2(2l+1))$. We prove that, if $L^{\infty}$ norm of $S_k^+(=\max\{S_k,0\})$ ... More
On the uniqueness for coagulation and multiple fragmentation equationAug 02 2012Mar 25 2013In this article, the uniqueness of weak solutions to the continuous coagulation and multiple fragmentation equation is proved for a large range of unbounded coagulation and multiple fragmentation kernels. The multiple fragmentation kernels may have a ... More
Poisson distribution of a prime counting function corresponding to elliptic curvesMar 03 2015Sep 27 2016Let $E$ be an elliptic curve defined over rational field $\mathbb{Q}$ and $N$ be a positive integer. Now, $M_E(N)$ denotes the number of primes $p$, such that the group $E_p(\mathbb{F}_p)$ is of order $N$. We show that $M_E(N)$ follows Poisson distribution ... More
On the Whittle Index for Restless Multi-armed Hidden Markov BanditsMar 15 2016We consider a restless multi-armed bandit in which each arm can be in one of two states. When an arm is sampled, the state of the arm is not available to the sampler. Instead, a binary signal with a known randomness that depends on the state of the arm ... More
Optimal Recommendation to Users that React: Online Learning for a Class of POMDPsMar 30 2016We describe and study a model for an Automated Online Recommendation System (AORS) in which a user's preferences can be time-dependent and can also depend on the history of past recommendations and play-outs. The three key features of the model that makes ... More
Pseudorandomness for concentration bounds and signed majoritiesNov 17 2014The problem of constructing pseudorandom generators that fool halfspaces has been studied intensively in recent times. For fooling halfspaces over the hypercube with polynomially small error, the best construction known requires seed-length O(log^2 n) ... More
$B_s^0 - \bar B_s^0$ mixing and $b \to s $ transitions in isosinglet down quark modelDec 05 2008The recent observation of the mass difference in $B_s$ system seems to be not in complete agreement with the corresponding standard model value. We consider the model with an extra vector like down quark to explain this discrepancy and obtain the constraints ... More
Convergence rates for linear and nonlinear inverse problems in Hilbert spaces via Holder stability estimatesDec 29 2018Feb 16 2019In this article, we look for a new kind of smoothness concept, i.e. Holder smoothness condition for finding the convergence rates of linear and nonlinear inverse problems in Hilbert spaces. The dependency of variational inequalities on the non-linearity ... More
Hydrodynamic simulations of viscous accretion flows around black holesDec 07 2011We study the time evolution of a rotating, axisymmetric, viscous accretion flow around black holes using a grid based finite difference method. We use the Shakura-Sunyaev viscosity prescription. However, we compare with the results obtained when all the ... More
Non-Hermitian quantum mechanics in non-commutative spaceJun 16 2008Jun 23 2008We study non Hermitian quantum systems in noncommutative space as well as a \cal{PT}-symmetric deformation of this space. Specifically, a \mathcal{PT}-symmetric harmonic oscillator together with iC(x_1+x_2) interaction is discussed in this space and solutions ... More
Convergence rates of nonlinear inverse problems in Banach spaces via Holder stability estimatesMay 30 2018In this paper, we analyze the convergence rates of Tikhonov regularization for solving the nonlinear ill-posed problems by using the Holder stability estimates as the smoothness condition. We obtain the convergence rates via two different approaches. ... More
Lackadaisical quantum walk for spatial searchNov 15 2018Feb 12 2019Lackadaisical quantum walk(LQW) has been an efficient technique in searching a target state from a database which is distributed on a two-dimensional lattice. We numerically study the quantum search algorithm based on the lackadaisical quantum walk on ... More
A Family of Non-commutative geometriesOct 21 2010It is shown that the non-commutativity in quantum Hall system may get modified. The self-adjoint extension of the corresponding Hamiltonian leads to a family of non-commutative geometries labeled by the self-adjoint extension parameters. We explicitly ... More
Observations on spacetime symmetry and non-commutativityDec 30 2008We consider both the co-ordinates and momenta to be non-commutative and define a non-commutative version of Lorentz symmetry which has a smooth limit to the standard Lorentz symmetry. The Poincar\acute{e} algebra in this spacetime has also been discussed. ... More
Stability, Reactivity, and Aromaticity of Compounds of a Multivalent SuperatomJul 03 2007In this communication we analyze the stability, reactivity and possible aromatic behavior of two recently reported clusters (Reveles J. U.; Khanna S. N.; Roach P. J.; Castleman A. W. jr. Proc. Natl. Acad. Sci, 2006, 103, 18405), viz., Al7C- and Al7O- ... More
Possible signatures of unparticles in rare annihilation type B decaysJul 23 2007Aug 20 2007We investigate the effect of unparticles in the pure annihilation type decays $B^- \to D_s^-\phi $ and $ D_s^- K^{*0}$. Since these decays have only annihilation contributions their branching ratios are expected to be very small in the standard model ... More
Study of FCNC mediated Z boson effect in the semileptonic rare baryonic decays $Λ_b \to Λl^+ l^- $Oct 13 2005We study the effect of the FCNC mediated $Z$ boson in the rare semileptonic baryonic decays $\Lambda_b \to \Lambda l^+ l^-$. We consider the model where the standard model fermion sector is extended by an extra vector like down quark, as a consequence ... More
Direct CP violation and new physics effects in the decay mode B^+ -> phi K^+Nov 02 2003Jun 29 2004We study the direct CP violation effect in the decay mode $B^+ \to \phi K^+$. This decay mode is dominated by the loop induced $\bar b \to \bar s s \bar s$ penguin diagram with a tiny contribution from annihilation diagram. Therefore, the standard model ... More
A problem involving the $p$-Laplacian operatorJan 15 2016Jan 29 2016Using a variational technique we guarantee the existence of a solution to the \emph{resonant Lane-Emden} problem $-\Delta_p u=\lambda |u|^{q-2}u$, $u|_{\partial\Omega}=0$ if and only if a solution to $-\Delta_p u=\lambda |u|^{q-2}u+f$, $u|_{\partial\Omega}=0$, ... More
Convergence rates for iteratively regularized Landweber iteration method for nonlinear inverse problems via Hölder stability estimatesMay 04 2018Feb 16 2019In this paper, the local convergence of Iteratively regularized Landweber iteration method is investigated for solving non-linear inverse problems in Banach spaces. Our analysis mainly relies on the assumption that the inverse mapping satisfies the Holder ... More
Sandpile Model with Activity InhibitionJun 25 1997A new sandpile model is studied in which bonds of the system are inhibited for activity after a certain number of transmission of grains. This condition impels an unstable sand column to distribute grains only to those neighbours which have toppled less ... More
On the properties of Ascent and Descent of Composition operator on Orlicz spacesJun 14 2016Nov 03 2016Here, the composition operators on Orlicz spaces with finite ascent and descent as well as infinite ascent and descent are characterized.
Convergence rates for iteratively regularized Landweber iteration method for nonlinear inverse problems via Hölder stability estimatesMay 04 2018Jun 25 2018In this paper, we discuss the local convergence of Iteratively regularized Landweber iteration method for solving non-linear inverse problems in Banach spaces. The basis of our analysis is based on the assumption that the inverse mapping satisfies the ... More
Study of some rare decays of B_s meson in the fourth generation modelOct 17 2011Dec 10 2011We study some rare decays of $B_s$ meson governed by the quark level transitions $ b \to s$, in the fourth generation model popularly known as SM4. Recently it has been shown that SM4, which is a simple extension of the SM3, can successfully explain several ... More
Study of FCNC mediated rare B_s decays in a single universal extra dimension scenarioNov 07 2006Jan 25 2007We study the rare semileptonic and radiative leptonic B_s decays in the universal extra dimension model. In this scenario, with a single extra dimension, there exists only one new parameter beyond those of the standard model, which is the inverse of the ... More
Probing new physics in B -> phi pi decayApr 09 2004May 01 2004We analyze the rare decay mode $B \to \phi \pi $, which is a pure penguin induced process, receiving dominant contribution from the electroweak penguins. Thus the standard model branching ratio is expected to be very small, which makes it as a sensitive ... More
Probing the unparticle signal in $b \to d $ penguin processesNov 22 2007Jan 11 2008We investigate the effect of unparticles in the pure $ b \to d $ penguin processes $ B^0 \to K^0 \bar K^0$ and $B^{+,0} \to \phi \pi^{+,0} $. Since these processes receive dominant contributions due to the {\it top} quark in the loop, direct and mixing-induced ... More
Can there be any new physics in b -> d penguinsAug 30 2004Dec 29 2004We analyze the possibility of observing new physics effects in the $b \to d$ penguin amplitudes. For this purpose, we consider the decay mode $B \to K^0 \bar K^0 $, which has only $b \to d$ penguin contributions. Using the QCD factorization approach, ... More
New physics effects on the CP asymmetries in B -> phi K_S and B -> eta' K_S decaysJun 05 2003Within the standard model (SM), the time dependent CP asymmetries in B -> psi K_S, B -> eta' K_S and B -> phi K_S are expected to give the same result i.e. sin (2 beta). However recent measurements of the mixing induced CP asymmetries in B -> phi K_S ... More
Numerical Simulations of a Two Component Advective Flow for The Study of the Spectral and Timing Properties of Black HolesApr 10 2014Two component advective flows are the most physical accretion disks which arise from theoretical consideration. Since viscosity is the determining factor, we investigate the effects of viscous stresses on accretion flows around a nonrotating black hole. ... More
Reduced limit approach to semilinear elliptic PDEs with measure dataApr 30 2016Sep 30 2016\noindent We study the following PDE \begin{align*} \begin{split} -L u + g\circ u & = \mu\,\,\mbox{in}\,\,\Omega,\\ u & = \nu\,\,\mbox{on}\,\,\partial\Omega, \end{split} \end{align*} where $L$ is a general linear elliptic operator, $\Omega$ is a bounded ... More
Heisenberg model and Rigged ConfigurationsJan 30 2015We show a correspondence of all the solutions of the spin-1/2 isotropic Heisenberg model for N=12 to the rigged configurations based on the comparison of the set of Takahashi quantum numbers in lexicographical order with the set of riggings of the rigged ... More
New bound on penguin pollution in B^0(t) --> pi^+ pi^-Jul 20 2002Aug 06 2002In the presence of penguin contributions, the indirect CP asymmetry in B^0(t) --> pi^+ pi^- measures sin 2alpha_{eff}, where alpha_{eff} deviates from the true value of the CKM phase alpha by an amount theta, i.e. alpha_{eff} = alpha + theta. Using the ... More
Convergence analysis of sectional methods for solving aggregation population balance equations: The fixed pivot techniqueMar 25 2013In this paper, we introduce the convergence analysis of the fixed pivot technique given by S.Kumar and Ramkrishna \cite{Kumar:1996-1} for the nonlinear aggregation population balance equations which are of substantial interest in many areas of science: ... More
Fourth generation effect on $Λ_b$ decaysOct 06 2010Nov 18 2010The rare decays of $\Lambda_b$ baryon governed by the quark level transitions $ b \to s$, are investigated in the fourth quark generation model popularly known as SM4. Recently it has been shown that SM4, which is a very simple extension of the standard ... More
Explaining B \to K pi anomaly with non-universal Z' bosonDec 10 2008We study the effect of non-universal $Z'$ boson in the decay modes $B \to K \pi$. In the standard model these modes receive dominant contributions from $b \to s$ QCD penguins. Therefore, in this limit one expects $S_{\pi^0 K^0} \approx \sin 2 \beta $, ... More