Results for "Aditya Chowdhury"

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Angular Momentum Content in Gas Rich Dwarf GalaxiesFeb 09 2017We derive the specific baryonic angular momentum of five gas rich dwarf galaxies from HI kinematics complemented by stellar mass profiles. Since the gas mass of these galaxies is much larger than the stellar mass, the angular momentum can be determined ... More
A Dearth of Atomic Hydrogen in NGC1052-DF2Oct 11 2018Oct 31 2018The recently claimed discovery of an ultra-diffuse galaxy lacking dark matter has important implications for alternate theories to dark matter as well as models of galaxy formation within the $\Lambda$CDM context. In this letter, we present a deep Giant ... More
Online Learning in Kernelized Markov Decision ProcessesMay 21 2018Jan 03 2019We consider online learning for minimizing regret in unknown, episodic Markov decision processes (MDPs) with continuous states and actions. We develop variants of the UCRL and posterior sampling algorithms that employ nonparametric Gaussian process priors ... More
A High Resolution Study of Carbon Radio Recombination Lines towards Cassiopeia AMar 13 2019Carbon Radio Recombination Lines trace the interface between molecular and atomic gas. We present GMRT observations of Carbon Radio Recombination Lines (CRRL), C$\alpha$244-C$\alpha$250 towards Cassiopeia A. We use a novel technique of stacking the emission ... 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
Misspecified Linear BanditsApr 23 2017We consider the problem of online learning in misspecified linear stochastic multi-armed bandit problems. Regret guarantees for state-of-the-art linear bandit algorithms such as Optimism in the Face of Uncertainty Linear bandit (OFUL) hold under the assumption ... More
Minimum cost distributed source coding over a networkApr 23 2007Aug 12 2009This work considers the problem of transmitting multiple compressible sources over a network at minimum cost. The aim is to find the optimal rates at which the sources should be compressed and the network flows using which they should be transmitted so ... More
Communicating the sum of sources over a networkMay 01 2008We consider a network (that is capable of network coding) with a set of sources and terminals, where each terminal is interested in recovering the sum of the sources. Considering directed acyclic graphs with unit capacity edges and independent, unit-entropy ... 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
Key distribution in PKC through QuantasMar 18 2010Cryptography literally means "The art & science of secret writing & sending a message between two parties in such a way that its contents cannot be understood by someone other than the intended recipient". and Quantum word is related with "Light". Thus, ... More
Machines of life: catalogue, stochastic process modeling, probabilistic reverse engineering and the PIs- from Aristotle to AlbertsMar 12 2012Mar 14 2012Molecular machines consist of either a single protein or a macromolecular complex composed of protein and RNA molecules. Just like their macroscopic counterparts, each of these nano-machines has an engine that "transduces" input energy into an output ... More
Consequences of the thermal dependence of spin orbit coupling in semiconductorsJul 24 2016The $\vec{k}.\vec{p}$ perturbation theory in semiconductor modifies some spin related parameters of the semi-conducting system. Furthermore, renormalization of the Kane model parameters occurs when temperature appears in the scenario. In this paper, we ... More
On $C^0$ Interior Penalty Method for Fourth Order Dirichlet Boundary Control Problem and an Alternative Error Analysis for Elliptic Cahn-Hilliard EquationAug 26 2018Nov 02 2018We revisit the energy space based Dirichlet boundary control problem governed by biharmonic equation investigated in \cite{CHOWDHURYDGcontrol2015}. The $L_{2}$ norm estimate in \cite{CHOWDHURYDGcontrol2015} is derived under an extra regularity assumption ... More
Traffic flow of interacting self-driven particles: rails and trails, vehicles and vesiclesApr 11 2003One common feature of a vehicle, an ant and a kinesin motor is that they all convert chemical energy, derived from fuel or food, into mechanical energy required for their forward movement; such objects have been modelled in recent years as {\it self-driven} ... More
Kane model parameters and stochastic spin currentAug 27 2015The spin current and spin conductivity is computed through thermally driven stochastic process. By evaluating the Kramers equation and with the help of $\vec{k}.\vec{p}$ method we have studied the spin Hall scenario. Due to the thermal assistance, the ... More
Centenary of "Researches on irritability of plants" by Jagadis Chandra BoseOct 13 2013This note celebrates the centenary of Jagadis Chandra Bose's classic monograph entitled "Researches on irritability of plants".
Inclusion Matrices and the MDS ConjectureNov 11 2015Nov 16 2015Let F_q be a finite field of order q with characteristic p. An arc is an ordered family of vectors in (F_q)^k in which every subfamily of size k is a basis of (F_q)^k. The MDS conjecture, which was posed by Segre in 1955, states that if k <= q, then an ... More
Collective effects in intra-cellular molecular motor transport: coordination, cooperation and competetionMay 06 2006Molecular motors do not work in isolation {\it in-vivo}. We highlight some of the coordinations, cooperations and competitions that determine the collective properties of molecular motors in eukaryotic cells. In the context of traffic-like movement of ... More
Stochastic mechano-chemical kinetics of molecular motors: a multidisciplinary enterprise from a physicist's perspectiveJul 25 2012Jun 04 2013A molecular motor is made of either a single macromolecule or a macromolecular complex. Just like their macroscopic counterparts, molecular motors "transduce" input energy into mechanical work. All the nano-motors considered here operate under isothermal ... More
Alice in a micro-factory: modeling materials and mechanisms of natural nano-machinesMay 16 2005Feb 19 2007Imagine an under water factory which is about $10 \mu$m long in each direction. The factory is filled with machines, each typically a few tens of nanometers long, which perform specfic tasks and operate in a well coordinated manner. A cell, the structural ... More
Immune Network: An Example of Complex Adaptive SystemsMar 03 1998The phenomenon of immunological memory has been known for a long time. But, the underlying mechanism is poorly understood. According to the theory of clonal selection the response to a specific invading antigen (e.g., bacteria) is offered by a specific ... More
Searching for targets on a model DNA: Effects of inter-segment hopping, detachment and re-attachmentAug 14 2007Jan 10 2010For most of the important processes in DNA metabolism, a protein has to reach a specific binding site on the DNA. The specific binding site may consist of just a few base pairs while the DNA is usually several millions of base pairs long. How does the ... More
100 years of Einstein's theory of Brownian motion: from pollen grains to protein trainsApr 24 2005Experimental verification of the theoretical predictions made by Albert Einstein in his paper, published in 1905, on the molecular mechanisms of Brownian motion established the existence of atoms. In the last 100 years discoveries of many facets of the ... More
Isotropy-Violation Diagnostics for $B$-mode Polarization Foregrounds to the Cosmic Microwave BackgroundApr 29 2016Sep 21 2016Isotropy-violation statistics can highlight polarized galactic foregrounds that contaminate primordial $B$-modes in the Cosmic Microwave Background (CMB). We propose a particular isotropy-violation test and apply it to polarized Planck 353 GHz data, constructing ... More
Active Ranking with Subset-wise PreferencesOct 23 2018We 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
Approximate unitary designs give rise to quantum channels with super additive classical capacityFeb 27 2019In a breakthrough, Hastings showed that there exist quantum channels whose classical capacity is superadditive i.e. more classical information can be transmitted by quantum encoding strategies entangled across multiple channel uses as compared to unentangled ... More
Decentralized Stochastic Control with a Word-of-Mouth CommunicationSep 24 2018In this paper, we analyze a network of agents that communicate with a word of mouth. This information structure is characterized by agents communicating only with their neighbors in the network. The link between two neighboring agents determines their ... More
Modeling Financial System with Interbank Flows, Borrowing, and InvestingJul 12 2017Oct 05 2018In our model, private actors with interbank cash flows similar to, but nore general than (Carmona, Fouque, Sun, 2013) borrow from the outside economy at a certain interest rate, controlled by the central bank, and invest in risky assets. Each private ... More
Modeling and Analysis of Walking Pattern for a Biped RobotAug 12 2015This paper addresses the design and development of an autonomous biped robot using master and worker combination of controllers. In addition, the bot is wirelessly controllable. The work presented here explains the walking pattern, system control and ... More
Sum-networks from incidence structures: construction and capacity analysisNov 07 2016A sum-network is an instance of a network coding problem over a directed acyclic network in which each terminal node wants to compute the sum over a finite field of the information observed at all the source nodes. Many characteristics of the well-studied ... More
Protection against link errors and failures using network codingMay 14 2009Aug 31 2010We propose a network-coding based scheme to protect multiple bidirectional unicast connections against adversarial errors and failures in a network. The network consists of a set of bidirectional primary path connections that carry the uncoded traffic. ... More
Rate and power allocation under the pairwise distributed source coding constraintJul 15 2008Jun 09 2009We consider the problem of rate and power allocation for a sensor network under the pairwise distributed source coding constraint. For noiseless source-terminal channels, we show that the minimum sum rate assignment can be found by finding a minimum weight ... More
Most probable failure scenario in a model power grid with random power demandSep 28 2013We consider a simple system with a local synchronous generator and a load whose power consumption is a random process. The most probable scenario of system failure (synchronization loss) is considered, and it is argued that its knowledge is virtually ... More
Improved compression of network coding vectors using erasure decoding and list decodingJun 01 2010Practical random network coding based schemes for multicast include a header in each packet that records the transformation between the sources and the terminal. The header introduces an overhead that can be significant in certain scenarios. In previous ... More
An On-chip Trainable and Clock-less Spiking Neural Network with 1R Memristive SynapsesSep 08 2017Nov 03 2017Spiking neural networks (SNNs) are being explored in an attempt to mimic brain's capability to learn and recognize at low power. Crossbar architecture with highly scalable Resistive RAM or RRAM array serving as synaptic weights and neuronal drivers in ... More
Efficiently estimating average fidelity of a quantum logic gate using few classical random bitsJan 22 2019We give three new algorithms for efficient in-place estimation, without using ancilla qubits, of average fidelity of a quantum logic gate acting on a d-dimensional system using much fewer random bits than what was known so far. Previous approaches for ... More
Active Contour Models for Manifold Valued Image SegmentationJun 26 2013Nov 11 2013Image segmentation is the process of partitioning a image into different regions or groups based on some characteristics like color, texture, motion or shape etc. Active contours is a popular variational method for object segmentation in images, in which ... More
Assessing the Effectiveness of Attack Detection at a Hackfest on Industrial Control SystemsSep 13 2018A hackfest named SWaT Security Showdown (S3) has been organized consecutively for two years. S3 has enabled researchers and practitioners to assess the effectiveness of methods and products aimed at detecting cyber attacks launched in real-time on an ... More
Packet Scheduling in Switches with Target Outflow ProfilesDec 29 2010The problem of packet scheduling for traffic streams with target outflow profiles traversing input queued switches is formulated in this paper. Target outflow profiles specify the desirable inter-departure times of packets leaving the switch from each ... More
A Novel Active Contour Model for Texture SegmentationJun 28 2013Texture is intuitively defined as a repeated arrangement of a basic pattern or object in an image. There is no mathematical definition of a texture though. The human visual system is able to identify and segment different textures in a given image. Automating ... More
Improved Lower Bounds for Coded CachingJan 24 2015Feb 15 2016Content delivery networks often employ caching to reduce transmission rates from the central server to the end users. Recently, the technique of coded caching was introduced whereby coding in the caches and coded transmission signals from the central ... More
On the multiple unicast capacity of 3-source, 3-terminal directed acyclic networksFeb 18 2013We consider the multiple unicast problem with three source-terminal pairs over directed acyclic networks with unit-capacity edges. The three $s_i-t_i$ pairs wish to communicate at unit-rate via network coding. The connectivity between the $s_i - t_i$ ... More
A note on the multiple unicast capacity of directed acyclic networksJan 17 2011Jan 24 2011We consider the multiple unicast problem under network coding over directed acyclic networks with unit capacity edges. There is a set of n source-terminal (s_i - t_i) pairs that wish to communicate at unit rate over this network. The connectivity between ... More
Communicating the sum of sources over a networkJan 29 2010Jan 22 2013We consider the network communication scenario, over directed acyclic networks with unit capacity edges in which a number of sources $s_i$ each holding independent unit-entropy information $X_i$ wish to communicate the sum $\sum{X_i}$ to a set of terminals ... More
Bounded negativity and Harbourne constants on ruled surfacesMar 05 2019Let $X$ be a smooth projective surface and let $\mathcal{C}$ be an arrangement of curves on $X$. The Harbourne constant of $\mathcal{C}$ was defined as a way to investigate the occurrence of curves of negative self-intersection on blow ups of $X$. This ... More
The log-Lévy moment problem via Berg-Urbanik semigroupsJun 07 2018We consider the Stieltjes moment problem for the Berg-Urbanik semigroups which form a class of multiplicative convolution semigroups on $\mathbb{R}_+$ that is in bijection with the set of Bernstein functions. Berg and Dur\'an proved that the law of such ... More
A New Window into Stochastic Gravitational Wave BackgroundDec 07 2011Sep 23 2013A stochastic gravitational wave background (SGWB) would gravitationally lens the cosmic microwave background (CMB) photons. We find that the lensing due to gravitational waves(GW) is more efficient as compared to lensing due to scalar density perturbations. ... More
node2vec: Scalable Feature Learning for NetworksJul 03 2016Prediction tasks over nodes and edges in networks require careful effort in engineering features used by learning algorithms. Recent research in the broader field of representation learning has led to significant progress in automating prediction by learning ... More
On Computation Rates for Arithmetic SumJan 26 2016For zero-error function computation over directed acyclic networks, existing upper and lower bounds on the computation capacity are known to be loose. In this work we consider the problem of computing the arithmetic sum over a specific directed acyclic ... More
Capacity of Sum-networks for Different Message AlphabetsApr 21 2015A sum-network is a directed acyclic network in which all terminal nodes demand the `sum' of the independent information observed at the source nodes. Many characteristics of the well-studied multiple-unicast network communication problem also hold for ... More
Replication based storage systems with local repairMay 24 2013We consider the design of regenerating codes for distributed storage systems that enjoy the property of local, exact and uncoded repair, i.e., (a) upon failure, a node can be regenerated by simply downloading packets from the surviving nodes and (b) the ... More
Cross Layer Adaptation for QoS in WSNOct 07 2011In this paper, we propose QoS aware MAC protocol for Wire- less Sensor Networks and its cross layer extension to network layer for providing QoS in delay sensitive WSN scenarios. In WSNs, there can be two types of traffic one is event driven traffic which ... More
Non-classical Tauberian and Abelian type criteria for the moment problemApr 28 2018The aim of this paper is to provide some new criteria for the Stieltjes moment problem. We first give a Tauberian type criterion for moment indeterminacy that is expressed purely in terms of the asymptotic behavior of the moment sequence (and its extension ... 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
The novel metallic states of the cuprates: topological Fermi liquids and strange metalsMay 11 2016Jul 17 2016This article is based on a talk by S.S. at the Nambu Memorial Symposium at the University of Chicago. We review ideas on the nature of the metallic states of the hole-doped cuprate high temperature superconductors, with an emphasis on the connections ... More
Spin transport in tilted electron vortex beamsMar 10 2016In this paper we have enlightened the spin related issues of tilted Electron vortex beams. We have shown that in the skyrmionic model of electron we can have the spin Hall current considering the tilted type of electron vortex beam. We have considered ... More
Effect of cosmic string on spin dynamicsNov 07 2014In the present paper, we have investigated the role of cosmic string on spin current and Hall electric field. Due to the background cosmic string, the modified electric field of the system generates renormalized spin orbit coupling, which induces a modified ... More
Effect of spin rotation coupling on spin transportSep 05 2013We have studied the spin rotation coupling(SRC) as an ingredient to explain different spin related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, ... More
Traffic of interacting ribosomes on mRNA during protein synthesis: effects of chemo-mechanics of individual ribosomesAug 09 2006Jan 10 2007Many {\it ribosomes} simultaneously move on the same messenger RNA (mRNA), each synthesizing separately a copy of the same protein. In contrast to the earlier models, here {\it we develop a ``unified'' theoretical model} that not only incorporates the ... More
Inertial effect on spin orbit coupling and spin transportFeb 05 2013May 20 2013We theoretically study the renormalization of inertial effects on the spin dependent transport of conduction electrons in a semiconductor by taking into account the interband mixing on the basis of k.p perturbation theory. In our analysis, for the generation ... More
The effect of inertia on the Dirac electron, the spin Hall current and the momentum space Berry curvatureJan 23 2013We have studied the spin dependent force and the associated momentum space Berry curvature in an accelerating system. The results are derived by taking into consideration the non relativistic limit of a generally covariant Dirac equation under the presence ... More
Interacting RNA polymerase motors on DNA track: effects of traffic congestion and intrinsic noise on RNA synthesisAug 08 2007Jan 10 2008RNA polymerase (RNAP) is an enzyme that synthesizes a messenger RNA (mRNA) strand which is complementary to a single-stranded DNA template. From the perspective of physicists, an RNAP is a molecular motor that utilizes chemical energy input to move along ... More
The effect of long range interactions on the stability of classical and quantum solidsJan 01 2008We generalise the celebrated Peierls' argument to study the stability of a long-range interacting classical solid. Long-range interaction implies that all the atomic oscillators are coupled to each other via a harmonic potential, though the coupling strength ... More
Nonparametric Depth and Quantile Regression for Functional DataJul 13 2016We investigate nonparametric regression methods based on spatial depth and quantiles when the response and the covariate are both functions. As in classical quantile regression for finite dimensional data, regression techniques developed here provide ... More
Study of hot and dense nuclear matter in effective QCD modelSep 28 2016In this thesis we use various effective QCD models to investigate hot and dense nuclear matter created in heavy ion collisions. To characterize such matter, we mainly exploit correlation functions and some of the associated spectral properties. We explore ... More
On the Security of the Cha-Ko-Lee-Han-Cheon Braid Group Public Key CryptosystemAug 20 2007Nov 15 2007We show that a number of cryptographic protocols using non-commutative semigroups including the Cha-Ko-Lee-Han-Cheon braid group public-key cryptosystem and related public-key cryptosystems such as the Shpilrain-Ushakov public-key cryptosystems are based ... More
On the security of new key exchange protocols based on the triple decomposition problemNov 14 2006Dec 06 2007We show that two new key exchange protocols with security based on the triple DP may have security based on the MSCSP.
Convergence Rates for Kernel Regression in Infinite Dimensional SpacesOct 31 2016Nov 15 2018We consider a nonparametric regression setup, where the covariate is a random element in a complete separable metric space, and the parameter of interest associated with the conditional distribution of the response lies in a separable Banach space. We ... More
A case study of Gröbner bases and Hilbert seriesJul 22 2015In this expository style of writing I will give an introduction of Gr\"{o}bner bases and compute it for some algebras and then show how to use it to compute Hilbert series for algebras from chains.
A Characterization of Consistent Digital Line Segments in Two DimensionsApr 28 2015May 01 2015Our concern is the digitalization of line segments in two dimensions as considered by Chun et al.[Discrete Comput. Geom., 2009] and Christ et al.[Discrete Comput. Geom., 2012]. The key property that differentiates the research of Chun et al. and Christ ... More
The CWKB approach to non-reflecting potential and cosmological implicationsJul 02 2002We discuss the method of calculating the reflection coefficient using complex trajectory WKB (CWKB) approximation. This enables us to give an interpretation of non-reflecting nature of the potential under certain conditions and clarify some points, reported ... More
Evolving eco-system: a network of networksMay 27 2004Ecology and evolution are inseparable. Motivated by some recent experiments, we have developed models of evolutionary ecology from the perspective of dynamic networks. In these models, in addition to the intra-node dynamics, which corresponds to an individual-based ... More
Slow scrambling in disordered quantum systemsAug 10 2016Recent work has studied the growth of commutators as a probe of chaos and information scrambling in quantum many-body systems. In this work we study the effect of static disorder on the growth of commutators in a variety of contexts. We find generically ... More
RNA polymerase motors on DNA track: effects of traffic congestion on RNA synthesisJun 14 2007Aug 08 2007RNA polymerase (RNAP) is an enzyme that synthesizes a messenger RNA (mRNA) strand which is complementary to a single-stranded DNA template. From the perspective of physicists, an RNAP is a molecular motor that utilizes chemical energy input to move along ... More
The novel metallic states of the cuprates: Fermi liquids with topological order, and strange metalsMay 11 2016Nov 23 2016This article is based on a talk by S.S. at the Nambu Memorial Symposium at the University of Chicago. We review ideas on the nature of the metallic states of the hole-doped cuprate high temperature superconductors, with an emphasis on the connections ... More
On the Asymptotic Analysis of Problems Involving Fractional Laplacian in Cylindrical Domains Tending to InfinitySep 22 2015Oct 27 2015The article is an attempt to investigate the issues of asymptotic analysis for problems involving fractional Laplacian where the domains tend to become unbounded in one-direction. Motivated from the pioneering work on second order elliptic problems by ... More
On the Plethora of Representations Arising in Noncommutative Quantum Mechanics and An Explicit Construction of Noncommutative 4-toriJul 04 2015Oct 20 2016We construct a two parameter family of unitarily equivalent irreducible representations of the triply extended group $\g$ of translations of $\mathbb{R}^{4}$ associated with one of its 4-dimensional coadjoint orbits and show how a continuous 1-parameter ... More
Fine-grained uncertainty relation and entropic uncertainty relation in the presence of quantum memoryJan 23 2012Apr 20 2012In presence of quantum memory [M. Berta, M. Christandl, R. Colbeck, J.M. Renes, and R. Renner, Nature Phys. 6, 659 (2010)] the lower bound of entropic uncertainty relation depends on amount of entanglement between the particle (on which two incompatible ... More
Stochastic Comparison of Parallel Systems with Log-Lindley Distributed Components under Random ShocksApr 11 2018Jan 30 2019Recently, Chowdhury and Kundu [6] compared two parallel systems of heterogeneous independent log-Lindley distributed components using the concept of vector majorization and related orders. Under the same set-up, this paper derives some results related ... More
Stochastic Comparisons of Lifetimes of Two Series and Parallel Systems with Location-Scale Family Distributed Components having Archimedean CopulasOct 02 2017In this paper, we compare the lifetimes of two series and two parallel systems stochastically where the lifetime of each component follows location-scale (LS) family of distributions. The comparison is carried out under two scenarios: one, that the components ... More
Coherent State Mapping Ring-Polymer Molecular Dynamics for Non-Adiabatic quantum propagationsJun 21 2017Nov 18 2017We introduce the coherent state mapping ring-polymer molecular dynamics (CS-RPMD), a new method that accurately describes electronic non-adiabatic dynamics with explicit nuclear quantization. This new approach is derived by using coherent state mapping ... More
Persistent Path Homology of Directed NetworksJan 03 2017Apr 13 2017While standard persistent homology has been successful in extracting information from metric datasets, its applicability to more general data, e.g. directed networks, is hindered by its natural insensitivity to asymmetry. We study a construction of homology ... More
Quasinormal modes of a charged spherical black hole with scalar hair for scalar and Dirac perturbationsJul 25 2018The quasinormal modes of charged and uncharged massive scalar fields and also of charged Dirac fields against the background of a charged spherical black hole endowed with a scalar hair have been investigated. Special emphasis has been given to the case ... More
Decentralized Task Allocation in Multi-Robot Systems via Bipartite Graph Matching Augmented with Fuzzy ClusteringJul 20 2018Robotic systems, working together as a team, are becoming valuable players in different real-world applications, from disaster response to warehouse fulfillment services. Centralized solutions for coordinating multi-robot teams often suffer from poor ... More
Salus: Fine-Grained GPU Sharing Primitives for Deep Learning ApplicationsFeb 12 2019GPU computing is becoming increasingly more popular with the proliferation of deep learning (DL) applications. However, unlike traditional resources such as CPU or the network, modern GPUs do not natively support fine-grained sharing primitives. Consequently, ... More
Low-complexity Decoding is Asymptotically Optimal in the SIMO MACApr 09 2014A single input multiple output (SIMO) multiple access channel, with a large number of transmitters sending symbols from a constellation to the receiver of a multi-antenna base station, is considered. The fundamental limits of joint decoding of the signals ... More
High-order asynchrony-tolerant finite difference schemes for partial differential equationsFeb 01 2017Synchronizations of processing elements (PEs) in massively parallel simulations, which arise due to communication or load imbalances between PEs, significantly affect the scalability of scientific applications. We have recently proposed a method based ... More
Evolutionary ecology in-silico: Does mathematical modelling help in understanding the "generic" trends?Apr 16 2005Motivated by the results of recent laboratory experiments (Yoshida et al. Nature, 424, 303-306 (2003)) as well as many earlier field observations that evolutionary changes can take place in ecosystems over relatively short ecological time scales, several ... More
Computer simulations of history of life: speciation, emergence of complex species from simpler organisms, and extinctionsNov 04 2003We propose a generic model of eco-systems, with a {\it hierarchical} food web structure. In our computer simulations we let the eco-system evolve continuously for so long that that we can monitor extinctions as well as speciations over geological time ... More
Interacting Generalised Cosmic Chaplygin gas in Loop quantum cosmology: A singularity free universeApr 13 2012In this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by Loop quantum cosmology. Dark energy in the form of Generalised Cosmic Chaplygin gas is considered. ... More
Theory for strength and stability of an unusual "ligand-receptor" bond: a microtubule attached to a wall by molecular motor tethersOct 16 2016A microtubule (MT) is a tubular stiff filament formed by a hierarchical organization of tubulin proteins. We develop a stochastic kinetic model for studying the strength and stability of a pre-formed attachment of a MT with a rigid wall where the MT is ... More
Quantum transport in ferromagnetic graphene: Role of Berry curvatureFeb 05 2016The magnetic effects in ferromagnetic graphene basically depend on the principle of exchange interaction when ferromagntism is induced by depositing an insulator layer on graphene. Here we deal with the consequences of non-uniformity in the exchange coupling ... More
Estimating the Sunyaev - Zel'dovich signal from quasar hosts using a Halo Occupation Distribution based approachDec 11 2015The Sunyaev-Zeldovich (SZ) effect is a spectral distortion in the Cosmic Microwave Background (CMB), caused due to up-scattering of CMB photons by high energy electron distributions. The largest SZ distortion in the CMB is caused by the hot electrons ... More
Global fits of the two-loop renormalized Two-Higgs-Doublet model with soft $Z_2$ breakingMar 27 2015Jun 10 2015We determine the next-to-leading order renormalization group equations for the Two-Higgs-Doublet model with a softly broken $Z_2$ symmetry and CP conservation in the scalar potential. We use them to identify the parameter regions which are stable up to ... More
Theory of dynamic force spectroscopy for kinetochore-microtubule attachments: rupture force distributionMay 28 2016Application of pulling force, under force-clamp conditions, to kinetochore-microtubule attachments {\it in-vitro} revealed a catch-bond-like behavior. In an earlier paper ({\it Sharma et al. Phys. Biol. (2014)} the physical origin of this apparently counter-intuitive ... More
Effect of non-uniform exchange field in ferromagnetic grapheneFeb 16 2015We have presented here the consequences of the non-uniform exchange field on the spin transport issues in spin chiral configuration of ferromagnetic graphene. Taking resort to the spin orbit coupling (SOC) term and non-uniform exchange coupling term we ... More
Single-enzyme kinetics with branched pathways: exact theory and series expansionDec 10 2014The progress of the successive rounds of catalytic conversion of substrates into product(s) by a single enzyme is characterized by the distribution of turnover times. Establishing the most general form of dependence of this distribution on the substrate ... More
Stochastic kinetics of a single headed motor protein: dwell time distribution of KIF1AApr 25 2010Mar 15 2011KIF1A, a processive single headed kinesin superfamily motor, hydrolyzes Adenosine triphosphate (ATP) to move along a filamentous track called microtubule. The stochastic movement of KIF1A on the track is characterized by an alternating sequence of pause ... More
Transcriptional bursts: a unified model of machines and mechanismsApr 08 2008Nov 28 2008{\it Transcription} is the process whereby RNA molecules are polymerized by molecular machines, called RNA polymerase (RNAP), using the corresponding DNA as the template. Recent {\it in-vivo} experiments with single cells have established that transcription ... More
On the Plethora of Representations Arising in Noncommutative Quantum Mechanics and An Explicit Construction of Noncommutative 4-toriJul 04 2015We construct a two parameter family of unitarily equivalent irreducible representations of the triply extended group $\g$ of translations of $\mathbb{R}^{4}$ associated with one of its 4-dimensional coadjoint orbits and show how a continuous 1-parameter ... More