Results for "Anupam Das"

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On the relative proof complexity of deep inference via atomic flowsFeb 20 2015Mar 05 2015We consider the proof complexity of the minimal complete fragment, KS, of standard deep inference systems for propositional logic. To examine the size of proofs we employ atomic flows, diagrams that trace structural changes through a proof but ignore ... More
Some properties of Generalized Fibonacci difference bounded and $p$-absolutely convergent sequencesApr 01 2016The main objective of this paper is to introduced a new sequence space $l_{p}(\hat{F}(r,s)),$ $ 1\leq p \leq \infty$ by using the band matrix $\hat{F}(r,s).$ We also establish a few inclusion relations concerning this space and determine its $\alpha-,\beta-,\gamma-$duals. ... More
Securing Tor Tunnels under the Selective-DoS AttackJul 19 2011Dec 18 2012Anonymous communication systems are subject to selective denial-of-service (DoS) attacks. Selective DoS attacks lower anonymity as they force paths to be rebuilt multiple times to ensure delivery which increases the opportunity for more attack. In this ... More
Some Fibonacci sequence spaces of non-absolute type derived from $\ell_{p} $ with $(1 \leq p \leq \infty)$ and Hausdorff measure of non-compactness of composition operatorsJun 18 2017The aim of the paper is to introduce the spaces $\ell_{\infty}^{\lambda}(\widehat{F})$ and $\ell_{p}^{\lambda}(\widehat{F})$ derived by the composition of the two infinite matrices $\Lambda=(\lambda_{nk})$ and $\widehat{F}=\left( f_{nk} \right),$ which ... More
Einstein relation and hydrodynamics of nonequilibrium mass transport processesJan 18 2017Jul 05 2017We obtain hydrodynamic descriptions of a broad class of conserved-mass transport processes on a ring. These processes are governed by chipping, diffusion and coalescence of masses, where microscopic probability weights in their nonequilibrium steady states, ... More
Exploring Ways To Mitigate Sensor-Based Smartphone FingerprintingMar 06 2015Modern smartphones contain motion sensors, such as accelerometers and gyroscopes. These sensors have many useful applications; however, they can also be used to uniquely identify a phone by measuring anomalies in the signals, which are a result from manufacturing ... More
On Nested Sequents for Constructive Modal LogicsMay 26 2015Sep 02 2015We present deductive systems for various modal logics that can be obtained from the constructive variant of the normal modal logic CK by adding combinations of the axioms d, t, b, 4, and 5. This includes the constructive variants of the standard modal ... More
On the logical complexity of cyclic arithmeticJul 26 2018Sep 11 2018We study the logical complexity of proofs in cyclic arithmetic ($\mathsf{CA}$), as introduced in Simpson '17, in terms of quantifier alternations of formulae occurring. Writing $C\Sigma_n$ for (the logical consequences of) cyclic proofs containing only ... More
On linear rewriting systems for Boolean logic and some applications to proof theoryOct 27 2016Nov 18 2016Linear rules have played an increasing role in structural proof theory in recent years. It has been observed that the set of all sound linear inference rules in Boolean logic is already coNP-complete, i.e. that every Boolean tautology can be written as ... More
A Functional (Monadic) Second-Order Theory of Infinite TreesMar 14 2019This paper presents a complete axiomatization of Monadic Second-Order Logic (MSO) over infinite trees. MSO on infinite trees is a rich system, and its decidability ("Rabin's Tree Theorem") is one of the most powerful known results concerning the decidability ... More
On linear rewriting systems for Boolean logic and some applications to proof theoryOct 27 2016Dec 27 2016Linear rules have played an increasing role in structural proof theory in recent years. It has been observed that the set of all sound linear inference rules in Boolean logic is already coNP-complete, i.e. that every Boolean tautology can be written as ... More
On linear rewriting systems for Boolean logic and some applications to proof theoryOct 27 2016Linear rules have played an increasing role in structural proof theory in recent years. It has been observed that the set of all sound linear inference rules in Boolean logic is already coNP-complete, i.e. that every Boolean tautology can be written as ... More
Some new Fibonacci difference spaces of non-absolute type and compact operatorsApr 25 2016The aim of the paper is to introduced the spaces $c_{0}^{\lambda}(\hat{F})$ and $c^{\lambda}(\hat{F})$ which are the BK-spaces of non-absolute type and also derive some inclusion relations. Further, we determine the $\alpha-,\beta-,\gamma-$duals of those ... More
Steady State of an Active Brownian Particle in Two-Dimensional Harmonic TrapFeb 11 2019Mar 14 2019We find an exact series solution for the steady-state probability distribution of a harmonically trapped active Brownian particle in two dimensions, in the presence of translational diffusion. This series solution allows us to efficiently explore the ... More
Ribet's construction of a suitable cusp eigenformOct 08 2009Oct 16 2009This article gives a self-contained exposition on Ribet's construction of a Hecke eigenform of weight 2 with certain congruence properties.
Light-cone spreading of perturbations and the butterfly effect in a classical spin chainNov 20 2017Jul 10 2018We find that localised perturbations in a chaotic classical many-body system-- the classical Heisenberg We find that the effects of a localised perturbation in a chaotic classical many-body system--the classical Heisenberg chain at infinite temperature--spread ... More
The Moduli Space of Totally Marked Degree Two Rational MapsAug 17 2014A rational map $\phi: \mathbb{P}^1 \to \mathbb{P}^1$ along with an ordered list of fixed and critical points is called a totally marked rational map. The space of totally marked degree two rational maps, $Rat^{tm}_2$ can be parametrized by an affine open ... More
Fingerprinting Smart Devices Through Embedded Acoustic ComponentsMar 13 2014The widespread use of smart devices gives rise to both security and privacy concerns. Fingerprinting smart devices can assist in authenticating physical devices, but it can also jeopardize privacy by allowing remote identification without user awareness. ... More
$e^+ e^- \to μ^+ μ^-$ scattering in the Noncommutative standard modelSep 18 2010We study muon pair production $ e^+ e^- \to \mu^+ \mu^-$ in the noncommutative(NC) extension of the standard model using the Seiberg-Witten maps of this to the second order of the noncommutative parameter $\Theta_{\mu \nu}$. Using $\mathcal{O}(\Theta^2)$ ... More
Neutral Higgs boson pair production at the LC in the Noncommutative Standard ModelSep 18 2010We study the Higgs boson pair production through $e^+e^-$ collision in the noncommutative(NC) extension of the standard model using the Seiberg-Witten maps of this to the first order of the noncommutative parameter $\Theta_{\mu \nu}$. This process is ... More
Deformation and break-up of viscoelastic droplets Using Lattice Boltzmann ModelsNov 09 2014We investigate the break-up of Newtonian/viscoelastic droplets in a viscoelastic/Newtonian matrix under the hydrodynamic conditions of a confined shear flow. Our numerical approach is based on a combination of Lattice-Boltzmann models (LBM) and Finite ... More
Generalisations of the Harer-Zagier recursion for 1-point functionsDec 31 2018Harer and Zagier proved a recursion to enumerate gluings of a $2d$-gon that result in an orientable genus $g$ surface, in their work on Euler characteristics of moduli spaces of curves. Analogous results have been discovered for other enumerative problems, ... More
Probing the Supersymmetric Inflaton and Dark Matter link via the CMB, LHC and XENON1T experimentsMay 12 2012Feb 05 2013The primordial inflation dilutes all matter except the quantum fluctuations which we see in the cosmic microwave background (CMB) radiation. Therefore the last phases of inflation must be embedded within a beyond the Standard Model (SM) sector where the ... More
Smartphone Fingerprinting Via Motion Sensors: Analyzing Feasibility at Large-Scale and Studying Real Usage PatternsMay 27 2016Jun 13 2016Advertisers are increasingly turning to fingerprinting techniques to track users across the web. As web browsing activity shifts to mobile platforms, traditional browser fingerprinting techniques become less effective; however, device fingerprinting using ... More
Defending Tor from Network Adversaries: A Case Study of Network Path PredictionOct 07 2014Mar 04 2015The Tor anonymity network has been shown vulnerable to traffic analysis attacks by autonomous systems and Internet exchanges, which can observe different overlay hops belonging to the same circuit. We aim to determine whether network path prediction techniques ... More
Multi-bit quantum random number generator from a single qubit quantum walkSep 21 2018We present a scheme for multi-bit quantum random number generation using a single qubit discrete-time quantum walk in one-dimensional space. Irrespective of the initial state of the qubit, quantum interference and entanglement of particle with the position ... More
The persistence of viscous effects in the overlap region, and the mean velocity in turbulent pipe and channel flowsAug 13 1997We argue that important elements of the dynamics of wall-bounded flows reside at the wall-normal position $y_p^+$ corresponding to the peak of the Reynolds shear stress. Specializing to pipe and channel flows, we show that the mean momentum balance in ... More
Gravitino production in hybrid inflationary modelsFeb 01 2000Jul 05 2000It has been recently shown that it is possible to excite gravitinos in an expanding background due to a time varying scalar field oscillating at the bottom of the inflationary potential. The two components of the gravitino, namely helicity 1/2 and helicity ... More
An Approach to Speed-up the Word Sense Disambiguation Procedure through Sense FilteringNov 19 2015In this paper, we are going to focus on speed up of the Word Sense Disambiguation procedure by filtering the relevant senses of an ambiguous word through Part-of-Speech Tagging. First, this proposed approach performs the Part-of-Speech Tagging operation ... More
Perturbations in higher derivative gravity beyond maximally symmetric spacetimesMay 08 2019We study (covariant) scalar-vector-tensor (SVT) perturbations of infinite derivative gravity (IDG), at the quadratic level of the action, around conformally-flat, covariantly constant curvature backgrounds which are not maximally symmetric spacetimes ... More
Interaction Rates in String Gas CosmologySep 15 2004We study string interaction rates in the Brandenberger-Vafa scenario, the very early universe cosmology of a gas of strings. This cosmology starts with the assumption that all spatial dimensions are compact and initially have string scale radii; some ... More
Towards (1+ε)-Approximate Flow SparsifiersOct 11 2013A useful approach to "compress" a large network $G$ is to represent it with a {\em flow-sparsifier}, i.e., a small network $H$ that supports the same flows as $G$, up to a factor $q \geq 1$ called the quality of sparsifier. Specifically, we assume the ... More
Unifying inflation and dark matter with neutrino massesAug 29 2007We propose a simple model where a {\it gauge invariant inflaton} is responsible for cosmic inflation and generates the seed for structure formation, while its relic {\it thermal} abundance explains the missing matter of the universe in the form of cold ... More
Is nonperturbative inflatino production during preheating a real threat to cosmology?Dec 05 2000Apr 10 2001We discuss toy models where supersymmetry is broken due to non-vanishing time-varying vacuum expectation value of the inflaton field during preheating. We discuss the production of inflatino the superpartner of inflaton due to vacuum fluctuations and ... More
$p$-Power conjugacy classes in $U(n,q)$ and $T(n,q)$May 10 2019Let $q$ be a $p$-power where $p$ is a fixed prime. In this paper, we look at the $p$-power maps on unitriangular group $U(n,q)$ and triangular group $T(n,q)$. In the spirit of Borel dominance theorem for algebraic groups, we show that the image of this ... More
Designing Parity Preserving Reversible CircuitsAug 04 2013Making a reversible circuit fault-tolerant is much more difficult than classical circuit and there have been only a few works in the area of parity-preserving reversible logic design. Moreover, all of these designs are ad hoc, based on some pre-defined ... More
Diffusion under time-dependent resettingDec 27 2015May 12 2016We study a Brownian particle diffusing under a time-modulated stochastic resetting mechanism to a fixed position. The rate of resetting r(t) is a function of the time t since the last reset event. We derive a sufficient condition on r(t) for a steady-state ... More
Exact Steady State of Active Brownian Particles in a 2D Harmonic TrapFeb 11 2019We find an exact series solution for the steady-state probability distribution of a harmonically trapped active Brownian particle in two dimensions, in the presence of translational diffusion. This series solution allows us to efficiently explore the ... More
On the variation of light curve parameters of RR Lyrae variables at multiple wavelengthsAug 24 2018Oct 04 2018We present a detailed light curve analysis of RR Lyrae variables at multiple wavelengths using Fourier decomposition method. The time-series data for RR Lyrae variables in the Galactic bulge and the Magellanic Clouds are taken from the Optical Gravitational ... More
Light Curve Parameters of Cepheid and RR Lyrae Variables at Multiple Wavelengths $-$ Models vs. ObservationsApr 17 2019We present results from a comparative study of light curves of Cepheid and RR Lyrae stars in the Galaxy and the Magellanic Clouds with their theoretical models generated from the stellar pulsation codes. Fourier decomposition method is used to analyse ... More
Field Theoretical Methods in CosmologySep 07 1995To optimally utilize all the exciting cosmological data coming in we need to sharpen also the theoretical tools available to cosmologists. One such indispensible tool to understand hot big bang cosmology is finite temperature field theory. We review and ... More
Quasar Production:Topological Defect Formation due to a Phase Transition linked with Massive NeutrinosApr 29 1994Recent observations of the space distribution of quasars indicate a very notable peak in space density at a redshift of $2$ to $3$.It is pointed out in this article that this may be the result of a phase transition which has a critical temperature of ... More
Tunnel splittings for one dimensional potential wells revisitedMar 08 2000The WKB and instanton answers for the tunnel splitting of the ground state in a symmetric double well potential are both reduced to an expression involving only the functionals of the potential, without the need for solving any auxilliary problems. This ... More
Antiferromagnetism and Superconductivity in UPt_3Mar 25 1998The short ranged antiferromagnetism recently seen in UPt_3 is proved incompatible with two dimensional (2D) order parameter models that take the antiferromagnetism as a symmetry breaking field. To adjust to the local moment direction, the order parameter ... More
Spin tunnelling in Molecular MagnetsDec 09 2000We study spin tunneling in magnetic molecules, with special reference to Fe8. The article aims to give a pedagogical discussion of what is meant by the tunneling of a spin, and how tunneling amplitudes or energy level splittings may be calculated using ... More
Vibrational Decoherence in Ion Trap Quantum ComputersOct 22 1997The ion trap quantum computer proposed by Cirac and Zoller is analyzed for decoherence due to vibrations of the ions. An adiabatic approximation exploiting the vast difference between the frequencies of the optical intraionic transition and the vibrational ... More
Decoherence in Ion Trap Quantum ComputersMar 29 1996The {\it intrinsic} decoherence from vibrational coupling of the ions in the Cirac-Zoller quantum computer [Phys. Rev. Lett. {\bf 74}, 4091 (1995)] is considered. Starting from a state in which the vibrational modes are at a temperature $T$, and each ... More
On collisions driven negative energy waves and Weibel instability of a relativistic electron beam in a quasi-neutral plasmaAug 29 2008Sep 02 2008A new quasi-neutral model describing the Weibel instability of a high-current relativistic beam propagating through a resistive plasma is developed. It treats beam electrons as kinetic particles, and ambient plasma as a non-relativistic fluid. For a finite-temperature ... More
Performance Analysis of Energy Harvesting Underlay Cooperative Cognitive Radio Relay Networks with Randomly Located NodesMar 04 2019In this work, we investigate the successful data communication probability of an energy harvesting co-operative cognitive radio network (CRN) in the presence of Poisson field of primary users (PU). We consider the scenario where, after harvesting energy ... More
Post-inflationary brane cosmologyAug 09 2000Feb 25 2001The brane cosmology has invoked new challenges to the usual Big Bang cosmology. In this paper we present a brief account on thermal history of the post-inflationary brane cosmology. We have realized that it is not obvious that the post-inflationary brane ... More
Interesting consequences of brane cosmologyJul 24 2000Apr 09 2001We discuss cosmology in four dimensions within a context of brane-world scenario.Such models can predict chaotic inflation with very low reheat temperature depending on the brane tension. We notice that the gravitino abundance is different in the brane-world ... More
Extra Dimensions and InflationFeb 17 1999Oct 26 1999It has been proposed that, without invoking supersymmetry, it is possible to solve the hierarchy problem provided the fundamental scale in the higher dimensional theory is at a much lower scale than the Planck scale. In this paper we consider a toy model ... More
The origin of dark matter, matter-anti-matter asymmetry, and inflationJun 27 2011A rapid phase of accelerated expansion in the early universe, known as inflation, dilutes all matter except the vacuum induced quantum fluctuations. These are responsible for seeding the initial perturbations in the baryonic matter, the non-baryonic dark ... More
Quenched Spin Tunneling and Diabolical Points in Magnetic Molecules: I. Symmetric ConfigurationsMar 08 2000The perfect quenching of spin tunneling that has previously been discussed in terms of interfering instantons, and has recently been observed in the magnetic molecule \Fe8, is treated using a discrete phase integral (or Wentzel-Kramers-Brillouin) method. ... More
Diabolical points in the magnetic spectrum of Fe_8 moleculesMar 07 2000The magnetic molecule Fe_8 has been predicted and observed to have a rich pattern of degeneracies in its spectrum as an external magnetic field is varied. These degeneracies have now been recognized to be diabolical points. This paper analyzes the diabolicity ... More
Phonoemissive Spin Tunneling in Molecular NanomagnetsOct 15 2011A new mechanism is proposed for the magnetization reversal of molecular nanomagnets such as \Fe8. In this process the spin tunnels from the lowest state near one easy direction to the first excited state near the opposite easy direction, and subsequently ... More
Coherent Magnetic Moment Reversal in Small Particles with Nuclear SpinsJul 13 1999A discrete WKB method is developed for calculating tunnel splittings in spin problems. The method is then applied to the issue of how nuclear spins affect the macroscopic quantum coherence of the total magnetic moment in small magnetic particles. The ... More
Low scale inflation with large number of e-foldingsOct 16 2003Oct 25 2003In this paper we illustrate an interesting example of low scale inflation with an extremely large number of e-foldings. This realization can be implemented easily in hybrid inflation model where usually inflation ends via phase transition. However this ... More
A model for fluctuating inflaton coupling: (s)neutrino induced adiabatic perturbations and non-thermal leptogenesisJun 03 2003Mar 26 2004We discuss an unique possibility of generating adiabatic density perturbations and leptogenesis from the spatial fluctuations of the inflaton decay rate. The key assumption is that the initial isocurvature perturbations are created in the right handed ... More
Inflatonic Q-ball evaporation: A new paradigm for reheating the UniverseNov 15 2002We show that the inflaton condensate associated with a global symmetry can fragment into quasi stable Q balls after the end of inflation, provided the inflaton oscillations give rise to an effective equation of state with negative pressure. We argue that ... More
Gravitational Collapse of Dark Energy Field ConfigurationsJul 29 2010It is now a well established fact based on several observations that we live in a Universe dominated by dark energy. The most natural candidates for dark energy are fields in curved space-time. We develop the formalism to study the gravitational collapse ... More
A small non-vanishing cosmological constant from vacuum energy: physically and observationally desirableDec 05 1994Dec 15 1995Increasing improvements in the independent determinations of the Hubble constant and the age of the universe now seem to indicate that we need a small non-vanishing cosmological constant to make the two independent observations consistent with each other. ... More
Neutrino Oscillations and LeptogenesisJan 18 2019The symmetry breaking of left right symmetric model around few TeV range permits the existence of massive right handed neutrinos or gauge bosons. In this work the decay of lightest right handed neutrinos in a class of minimal left right symmetric model ... More
On units generated by Euler systemsOct 08 2009In the context of cyclotomic fields, it is still unknown whether there exist Euler systems other than the ones derived from cyclotomic units. Nevertheless, we first give an exposition on how norm-compatible units are generated by any Euler system, following ... More
Discrete phase integral method for five-term recursion relationsMar 08 2000A formalism is developed to study certain five-term recursion relations by discrete phase integral (or Wentzel-Kramers-Brillouin) methods. Such recursion relations arise naturally in the study of the Schrodinger equation for certain spin Hamiltonians. ... More
Agnostic Detector Error, Wigner Functions, and the Classical Limit of the High-Spin Einstein-Podolsky-Rosen ExperimentNov 29 2018The spin-$j$ Einstein-Podolsky-Rosen experiment is studied with a view to understanding how classical behaviour emerges as $j \to \infty$. It is proposed that it is necessary to include detector error, which if it is be to viewed as an essential aspect ... More
Spatiotemporal Feature Learning for Event-Based VisionMar 16 2019Unlike conventional frame-based sensors, event-based visual sensors output information through spikes at a high temporal resolution. By only encoding changes in pixel intensity, they showcase a low-power consuming, low-latency approach to visual information ... More
On Upper Bounds with $ABC=2^m p^n$ and $ABC= 2^m p^n q^r$ with $p$ and $q$ as Mersenne or Fermat PrimesSep 06 2018Per the $ABC$ conjecture, for every $\varepsilon > 0$, there exist finitely many triples $\{A, B, C\}$, satisfying $A + B = C, gcd(A,B) = 1, B > A \geq 1$, such that $C > rad(ABC)^{1 + \varepsilon}$, where $rad(ABC)$ is the product of all distinct primes ... More
Dynamics of Snapping Beams and Jumping PoppersOct 14 2013Feb 20 2014We consider the dynamic snapping instability of elastic beams and shells. Using the Kirchhoff rod and F\"{o}ppl-von K\'{a}rm\'{a}n plate equations, we study the stability, deformation modes, and snap-through dynamics of an elastic arch with clamped boundaries ... More
Nanodot to Nanowire: A strain-driven shape transition in self-organized endotaxial CoSi2 on Si (100)May 04 2012We report a phenomenon of strain-driven shape transition in the growth of nanoscale self-organized endotaxial CoSi2 islands on Si (100) substrates. Small square shaped islands as small as 15\times15 nm2 have been observed. Islands grow in the square shape ... More
Baryogenesis, dark matter and inflation in the Next-to-Minimal Supersymmetric Standard ModelSep 19 2013Sep 23 2013Explaining baryon asymmetry, dark matter and inflation are important elements of a successful theory that extends beyond the Standard Model of particle physics. In this paper we explore these issues within the Next-to-Minimal Supersymmetric Standard Model ... More
Representation Theory of Finite GroupsJan 04 2010The point of view of these notes on the topic is to bring out the flavor that Representation Theory is an extension of the first course on Group Theory. We also emphasize the importance of base field. These notes cover completely the theory over complex ... More
Binary-Fluid Turbulence: Signatures of Multifractal Droplet Dynamics and Dissipation ReductionDec 31 2015Apr 09 2016We present an extensive direct numerical simulation of statistically steady, homogeneous, isotropic turbulence in two-dimensional, binary-fluid mixtures with air-drag-induced friction by using the Cahn-Hilliard-Navier-Stokes equations. We choose parameters, ... More
Early Universe cosmology and supergravityJun 30 2003In this talk I will describe the role of supersymmetric flat directions in the early Universe cosmology. Particularly I will discuss how supergravity effects lift the flat direction potential and leads to interesting cosmological consequences.
Time auto-correlation function and Green-Kubo formula: A study on disordered harmonic chainSep 02 2010Feb 18 2014We have considered heat conduction in a one-dimensional mass disordered harmonic chain of $N$ particles connected to two Langevin type reservoirs at different temperatures. An exact expression for the boundary heat current-current auto-correlation function ... More
Projective varieties covered by isotrivial familiesOct 25 2011Jan 24 2013Let X,Y be projective schemes over a discrete valuation ring R, where Y is generically smooth and g:X \to Y a surjective R-morphism such that g_*\mathcal{O}_X = \mathcal{O}_Y. We show that if the family X \to Spec(R) is isotrivial, then the generic fiber ... More
Conjugacy Classes of Centralizers in $G_2$Apr 23 2008Let $G$ be an algebraic group of type $G_2$ over a field $k$ of characteristic $\neq 2,3$. In this paper we calculate centralizers of semisimple elements in anisotropic $G_2$. Using these, we show explicitly that there are six conjugacy classes of centralizers ... More
Quenched Spin Tunneling and Diabolical Points in Magnetic Molecules: II. Asymmetric ConfigurationsMar 09 2000The perfect quenching of spin tunneling first predicted for a model with biaxial symmetry, and recently observed in the magnetic molecule Fe_8, is further studied using the discrete phase integral (or Wentzel-Kramers-Brillouin) method. The analysis of ... More
Oscillatory Tunnel Splittings in Spin Systems: A Discrete Wentzel-Kramers-Brillouin ApproachJul 09 1999Certain spin Hamiltonians that give rise to tunnel splittings that are viewed in terms of interfering instanton trajectories, are restudied using a discrete WKB method, that is more elementary, and also yields wavefunctions and preexponential factors ... More
Vibrational Decoherence in Ion-Trap Quantum ComputersMar 25 1998Decoherence is studied in an attractive proposal for an actual implementation of a quantum computer based on trapped ions. Emphasis is placed on the decoherence arising from the vibrational motion of the ions, which is compared with that due to spontaneous ... More
Large transverse field tunnel splittings in the Fe_8 spin HamiltonianJun 14 1999The spin Hamiltonian that describes the molecular magnet Fe$_8$ has biaxial symmetry with mutually perpendicular easy, medium, and hard magnetic axes. Previous calculations of the ground state tunnel splittings in the presence of a magnetic field along ... More
Lattice Distortion Mediated Paramagnetic Relaxation in High-Spin High-Symmetry Molecular MagnetsMay 11 1998Field-dependent maxima in the relaxation rate of the magnetic molecules Mn_12-Ac and Fe_8-tacn have commonly been ascribed to some resonant tunneling phenomenon. We argue instead that the relaxation can be understood as purely due to phonons. The rate ... More
Selmer Groups of Elliptic Curves with Complex MultiplicationOct 08 2009This paper contains some results regarding the Iwasawa module structure of Selmer groups of elliptic curves with complex multiplication.
Scaling in the Aging Dynamics of the Site-diluted Ising ModelJun 21 2013We study numerically the phase-ordering kinetics of the two-dimensional site-diluted Ising model. The data can be interpreted in a framework motivated by renormalization-group concepts. Apart from the usual fixed point of the non-diluted system, there ... More
Dynamical Theory of the Inverted Cheerios EffectApr 06 2017Recent experiments have shown that liquid drops on highly deformable substrates exhibit mutual interactions. This is similar to the Cheerios effect, the capillary interaction of solid particles at a liquid interface, but now the roles of solid and liquid ... More
CMB constraints on non-thermal leptogenesisAug 02 2003Nov 22 2003Leptogenesis is at the heart of particle cosmology which requires physics beyond the Standard Model. There are two possibilities of realizing leptogenesis; thermal and non-thermal. Both are viable given the scale of inflation and the constraint on the ... More
Real Elements in Spin GroupsApr 08 2008Let $F$ be a field of characteristic $\neq 2$. Let $G$ be an algebraic group defined over $F$. An element $t\in G(F)$ is called {\bf real} if there exists $s\in G(F)$ such that $sts^{-1}=t^{-1}$. A semisimple element $t$ in $GL_n(F), SL_n(F), O(q), SO(q), ... More
Spin tunnelling in mesoscopic systemsDec 09 2000We study spin tunnelling in molecular magnets as an instance of a mesoscopic phenomenon, with special emphasis on the molecule Fe8. We show that the tunnel splitting between various pairs of Zeeman levels in this molecule oscillates as a function of applied ... More
Application of the discrete Wentzel-Kramers-Brillouin method to spin tunnelingJul 13 1999A discrete version of the WKB method is developed and applied to calculate the tunnel splittings between classically degenerate states of spin Hamiltonians. The results for particular model problems are in complete accord with those previously found using ... More
Performance Analysis of Ultra Wideband Receivers for High Data Rate Wireless Personal Area Network SystemMar 18 2010For high data rate ultra wideband communication system, performance comparison of Rake, MMSE and Rake-MMSE receivers is attempted in this paper. Further a detail study on Rake-MMSE time domain equalizers is carried out taking into account all the important ... More
Various Non-autonomous Notions for Borel MeasuresJun 13 2018We introduce and investigate the notions of expansiveness, topological stability and persistence for Borel measures with respect to time varying bi-measurable maps on metric spaces. We prove that expansive persistent measures are topologically stable ... More
Stability Theorems for Group Actions on Uniform SpacesFeb 18 2018May 24 2018We extend the notions of topological stability, shadowing and persistence from homeomorphisms to finitely generated group actions on uniform spaces and prove that an expansive action with either shadowing or persistence is topologically stable. Using ... More
On the Extension of the Gaussian Moat ProblemJan 28 2019In this paper, we have developed an algorithm for the prime searching in $\mathbb{R}^3$. This problem was proposed by M. Das [Arxiv,2019]. This paper is an extension of her work. As we know the distribution of primes will get more irregular as we are ... More
Dynamics under radiation damping from ab initio formalism -nonlocal restraint on acceleration runaway from radiation recoil in electrodynamicsJul 12 2005Mar 19 2018The classically encountered problem of acceleration runaway of radiation recoiled charged particle is addressed by ab-initio variational approach for electrodynamics. The dynamic paths of stationary action evolving with minimum loss of self field energy ... More
Model independent New Physics analysis in $Λ_b\toΛμ^+μ^-$ decayFeb 26 2018Mar 19 2018We study the rare $\Lambda_b\to\Lambda\mu^+\mu^-$ decay in the Standard Model and beyond. Beyond the Standard Model we include new vector and axial-vector operators, scalar and pseudo-scalar operators, and tensor operators in the effective Hamiltonian. ... More
Quarkonia production at forward rapidity in Pb+Pb collisions at $\bf \sqrt{s_{\rm NN}}=2.76$ TeV with the ALICE detectorNov 25 2011The study of formation of heavy quarkonia in relativistic heavy ion collisions provides important insight into the properties of the produced high density QCD medium. Lattice QCD studies show sequential suppression of quarkonia states with increasing ... More
Frictional damping in radiative electrodynamics and its scaling to macroscopic systemsJun 06 2011Radiation force in Abraham-Lorentz-Dirac equation is revisited for possible signature of irreversible action in the dynamics. The analysis shows that the classical electron can 'dissipate' out a certain fraction of field energy that distinguishes itself ... More
Geometric EntropyJul 23 2010The laws of mechanics of stationary black holes bear a close resemblance with the laws of thermodynamics. This is not only a mathematical analogy but also a physical one that helps us answer deep questions related to the thermodynamic properties of the ... More
Generating Conditional Probabilities for Bayesian Networks: Easing the Knowledge Acquisition ProblemNov 12 2004Aug 04 2008The number of probability distributions required to populate a conditional probability table (CPT) in a Bayesian network, grows exponentially with the number of parent-nodes associated with that table. If the table is to be populated through knowledge ... More
Almost-sure quasiperiodicity in countably many co-existing circlesDec 09 2016In many dynamical systems, countably infinitely many invariant tori co-exist. The occurrence of quasiperiodicity on any one of these tori is sometimes sufficient to establish strong global properties, like dense trajectories and periodic points. In this ... More