Results for "Sridhar Ravi"

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The viscosity radius in dilute polymer solutions: Universal behaviour from DNA rheology and Brownian dynamics simulationsMay 16 2014Oct 14 2014The swelling of the viscosity radius, $\alpha_\eta$, and the universal viscosity ratio, $U_{\eta R}$, have been determined experimentally for linear DNA molecules in dilute solutions with excess salt, and numerically by Brownian dynamics simulations, ... More
Bees with attitude: the effect of gusts on flight dynamicsFeb 10 2018Flight is a complicated task at small scales in part due to the ubiquitous unsteady air which contains it. Flying organisms deal with these difficulties using active and passive control mechanisms to steer their body motion. Body attitudes of flapping ... More
Representation Policy IterationJul 04 2012This paper addresses a fundamental issue central to approximation methods for solving large Markov decision processes (MDPs): how to automatically learn the underlying representation for value function approximation? A novel theoretically rigorous framework ... More
Enhanced Secure Algorithm for Message CommunionOct 08 2011This paper puts forward a safe mechanism of data transmission to tackle the security problem of information which is transmitted in Internet. The encryption standards such as DES (Data Encryption Standard), AES (Advanced Encryption Standard) and EES (Escrowed ... More
Decision-Theoretic Planning with Concurrent Temporally Extended ActionsJan 10 2013We investigate a model for planning under uncertainty with temporallyextended actions, where multiple actions can be taken concurrently at each decision epoch. Our model is based on the options framework, and combines it with factored state space models,where ... More
Entrainment and mixing in gravity currents using simultaneous velocity-density measurementsFeb 07 2018Gravity currents modify their flow characteristics by entraining ambient fluid, which depends on a variety of governing parameters such as the initial density, $\Delta \rho$, the total initial height of the fluid, $H$, and the slope of the terrain, $\alpha$, ... More
Sparse Q-learning with Mirror DescentOct 16 2012This paper explores a new framework for reinforcement learning based on online convex optimization, in particular mirror descent and related algorithms. Mirror descent can be viewed as an enhanced gradient method, particularly suited to minimization of ... More
Non-quasiparticle microwave absorption in $Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}$Apr 07 2000We show that a non-quasiparticle charge collective mode, in parallel and coincident with the d-wave pair conductivity, leads to a quantitative understanding of microwave surface impedance measurements on superconducting $Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta}$. ... More
A Diagonal Representation of Quantum Density Matrix Using q-Boson Oscillator Coherent StatesAug 16 2002A q-analogue of Sudarshan's diagonal representation of the Quantum Mechanical density matrix is obtained using q-boson coherent states. Earlier result of Mehta and Sudarshan on the self reproducing property of rho(z',z) is also generalized and a self-consistent ... More
Trust Based Scheme for QoS Assurance in Mobile Ad-Hoc NetworksFeb 08 2012A mobile ad-hoc network (MANET) is a peer-to-peer wireless network where nodes can communicate with each other without the use of infrastructure such as access points or base stations. These networks are self-configuring, capable of self-directed operation ... More
$η_c$ production and dimuon enhancement in heavy ion collisionsJan 14 2003Dilepton production in heavy ion collisions, in the Intermediate Mass Region (IMR) has consistently shown an excess over theoretical estimates. An attempt to understand this discrepancy between the observed dilepton pairs and the theoretical estimate ... More
Gamma^*, Z^* production in polarised p-p scattering as a probe of the proton spin structureOct 01 1993We present the results of a detailed study of the large transverse momentum Drell-Yan process, pp --> (Gamma^*, Z^*)X --> l^+l^- X at collider energies, with either one or both protons polarised, allowing the study of single- and double-spin asymmetries ... More
Colour-octet Contributions to $x_F$ Distributions in $J/ψ$ Hadro-production at Fixed Target EnergiesAug 24 1996Sep 09 1996We study J/\psi production at fixed-target energies, including the colour-octet production mechanisms predicted by NRQCD. In an earlier paper, we found that the octet components were crucial in understanding p_T-integrated forward (x_F > 0) cross-sections. ... More
Recursions, formulas, and graph-theoretic interpretations of ramified coverings of the sphere by surfaces of genus 0 and 1Dec 17 1998We derive a closed-form expression for all genus 1 Hurwitz numbers, and give a simple new graph-theoretic interpretation of Hurwitz numbers in genus 0 and 1. (Hurwitz numbers essentially count irreducible genus g covers of the sphere, with arbitrary specified ... More
Active Model Aggregation via Stochastic Mirror DescentMar 28 2015We consider the problem of learning convex aggregation of models, that is as good as the best convex aggregation, for the binary classification problem. Working in the stream based active learning setting, where the active learner has to make a decision ... More
The enumerative geometry of rational and elliptic curves in projective spaceSep 05 1997We study the geometry of varieties parametrizing degree d rational and elliptic curves in P^n intersecting fixed general linear spaces and tangent to a fixed hyperplane H with fixed multiplicities along fixed general linear subspaces of H. As an application, ... More
Sharp edge, vertex, and mixed Cheeger type inequalities for finite Markov kernelsJun 07 2006May 05 2007We show how the evolving set methodology of Morris and Peres can be used to show Cheeger inequalities for bounding the spectral gap of a finite Markov kernel. This leads to sharp versions of several previous Cheeger inequalities, including ones involving ... More
Eigenvalues of non-reversible Markov chains: their connection to mixing timesApr 17 2006May 07 2007This paper originally showed a lower bound on mixing time for a non-reversible Markov chain in terms of its largest non-trivial eigenvalue, and used this to re-derive some generalizations of results of Fan Chung. However, the paper has been withdrawn ... More
Solving Society's Big Ills, A Small StepMar 19 2016Sep 26 2016We look at a collection of conjectures with the unifying message that smaller social systems, tend to be less complex and can be aligned better, towards fulfilling their intended objectives. We touch upon a framework, referred to as the four pronged approach ... More
Dynamic Multi-Factor Bid-Offer Adjustment Model: A Feedback Mechanism for Dealers (Market Makers) to Deal (Grapple) with the Uncertainty Principle of the Social SciencesJan 01 2016Feb 02 2016The author seeks to develop a model to alter the bid-offer spread, currently quoted by market makers, that varies with the market and trading conditions. The dynamic nature of financial markets and trading, as with the rest of social sciences, where changes ... More
The Circle of Investment: Connecting the Dots of the Portfolio Management Cycle...Mar 19 2016Mar 31 2016We will look at the entire cycle of the investment process relating to all aspects of, formulating an investment hypothesis, constructing a portfolio based on that, executing the trades to implement it, on-going risk management, periodically measuring ... More
A Tale of Two Consequences: Intended and Unintended Outcomes of the Japan TOPIX Tick Size ChangesFeb 02 2016May 21 2016We look at the effect of the tick size changes on the TOPIX 100 index names made by the Tokyo Stock Exchange on Jan-14-2014 and Jul-22-2104. The intended consequence of the change is price improvement and shorter time to execution. We look at security ... More
Fighting Uncertainty with UncertaintyJan 14 2016Jul 11 2016We can overcome uncertainty with uncertainty. Using randomness in our choices and in what we control and hence in the decision making process could potentially offset the uncertainty inherent in the environment and yield better outcomes. This methodology ... More
Genus g Gromov-Witten invariants of Del Pezzo surfaces: Counting plane curves with fixed multiple pointsSep 04 1997As another application of the degeneration methods of [V3], we count the number of irreducible degree $d$ geometric genus $g$ plane curves, with fixed multiple points on a conic $E$, not containing $E$, through an appropriate number of general points ... More
The characteristic numbers of quartic plane curvesDec 02 1998The characteristic numbers of smooth plane quartics are computed using intersection theory on a component of the moduli space of stable maps. This completes the verification of Zeuthen's prediction of characteristic numbers of smooth plane curves. A short ... More
Radio Interferometers with wide bandwidthsOct 08 2003The Australia Telescope Compact Array and the Very Large Array are currently being upgraded to operate with wide bandwidths; interferometers dedicated to the measurement of cosmic microwave background anisotropies are being designed with large instantaneous ... More
Determination Of Optimal Number Of Clusters In Wireless Sensor NetworksAug 09 2012Prolonged network lifetime, scalability and efficient load balancing are essential for optimal performance of a wireless sensor network. Clustering provides an effective way of extending the lifetime of a sensor network. Clustering is the process that ... More
Prodirect Manipulation: Bidirectional Programming for the MassesOct 22 2015Feb 24 2016Software interfaces today generally fall at either end of a spectrum. On one end are programmable systems, which allow expert users (i.e. programmers) to write software artifacts that describe complex abstractions, but programs are disconnected from their ... More
On a nonlocal extension of differentiationSep 17 2015Mar 21 2016We study an integral equation that extends the problem of anti-differentiation. We formulate this equation by replacing the classical derivative with a known nonlocal operator similar to those applied in fracture mechanics and nonlocal diffusion. We show ... More
Duality and evolving set bounds on mixing timesJul 02 2006We sharpen the Evolving set methodology of Morris and Peres and extend it to study convergence in total variation, relative entropy, $L^2$ and other distances. Bounds in terms of a modified form of conductance are given which apply even for walks with ... More
A geometric Littlewood-Richardson ruleFeb 24 2003We describe an explicit geometric Littlewood-Richardson rule, interpreted as deforming the intersection of two Schubert varieties so that they break into Schubert varieties. There are no restrictions on the base field, and all multiplicities arising are ... More
Financial Services, Economic Growth and Well-Being: A Four-Pronged StudyMar 03 2016A four-pronged approach to dealing with Social Science Phenomenon is outlined. This methodology is applied to Financial Services, Economic Growth and Well-Being. The four prongs are like the four directions for an army general looking for victory. Just ... More
Securities Lending Strategies, Exclusive Auction BidsMar 03 2016May 09 2016The objective is either to design an appropriate securities lending auction mechanism or to come up with a strategy for placing bids, depending on which side of the fence a participant sits. There are two pieces to this puzzle. One is the valuation of ... More
Promising outcomes of an online course in research writing at a Rwandan universityOct 05 2012Background: Researchers in developing countries often do not have access to training on research writing. The purpose of this study was to test whether researchers in Rwanda might complete and benefit from a pilot online course in research writing. Methods: ... More
Rates of convergence for Smoluchowski's coagulation equationsMay 21 2009Apr 24 2011We establish nearly optimal rates of convergence to self-similar solutions of Smoluchowski's coagulation equation with kernels $K = 2$, $x + y$, and $xy$. The method is a simple analogue of the Berry-Ess\'een theorem in classical probability and requires ... More
Rapid mixing in Markov chainsApr 28 2003A wide class of ``counting'' problems have been studied in Computer Science. Three typical examples are the estimation of - (i) the permanent of an $n\times n$ 0-1 matrix, (ii) the partition function of certain $n-$ particle Statistical Mechanics systems ... More
On an Inequality of Dimension-like Invariants for Finite GroupsFeb 02 2015In this paper, we introduce several notions of "dimension" of a finite group, involving sizes of generating sets and certain configurations of maximal subgroups. We focus on the inequality $m(G) \leq \mathrm{MaxDim}(G)$, giving a family of examples where ... More
The moduli space of curves and Gromov-Witten theoryFeb 16 2006Feb 20 2006The goal of this article is to motivate and describe how Gromov-Witten theory can and has provided tools to understand the moduli space of curves. For example, ideas and methods from Gromov-Witten theory have led to both conjectures and theorems showing ... More
Intersection conductance and canonical alternating paths, methods for general finite Markov chainsNov 19 2006Dec 05 2011We extend the conductance and canonical paths methods to the setting of general finite Markov chains, including non-reversible non-lazy walks. The new path method is used to show that a known bound for mixing time of a lazy walk on a Cayley graph with ... More
Microstructure under the Microscope: Combining Dimension Reduction, Distance Measures and CovarianceMar 30 2016May 04 2016Market Microstructure is the investigation of the process and protocols that govern the exchange of assets with the objective of reducing frictions that can impede the transfer. In financial markets, where there is an abundance of recorded information, ... More
ATCA and CMB anisotropiesAug 27 2001Australia Telescope Compact Array (ATCA) observations in sky regions selected to be low in foreground confusion have been used to infer limits on arcmin-scale CMB anisotropy in total intensity and polarization. These deep searches have, hitherto, been ... More
An invariant in shock clustering and Burgers turbulenceJun 15 2011Jan 06 20121-D scalar conservation laws with convex flux and Markov initial data are now known to yield a completely integrable Hamiltonian system. In this article, we rederive the analogue of Loitsiansky's invariant in hydrodynamic turbulence from the perspective ... More
Vertex and edge expansion properties for rapid mixingOct 26 2004We show a strict hierarchy among various edge and vertex expansion properties of Markov chains. This gives easy proofs of a range of bounds, both classical and new, on chi-square distance, spectral gap and mixing time. The 2-gradient is then used to give ... More
Securities Lending Strategies, Valuation of Term Loans using Option TheorySep 06 2016Sep 19 2016We develop models to price long term loans in the securities lending business. These longer horizon deals can be viewed as contracts with optionality embedded in them and can be priced using established methods from derivatives theory, becoming to our ... More
Counting curves of any genus on rational ruled surfacesSep 04 1997In this paper we study the geometry of the Severi varieties parametrizing curves on the rational ruled surface $\fn$. We compute the number of such curves through the appropriate number of fixed general points on $\fn$, and the number of such curves which ... More
Hong Kong - Shanghai Connect / Hong Kong - Beijing Disconnect (?), Scaling the Great Wall of Chinese Securities Trading CostsMar 04 2016Jun 29 2016We utilize a fundamentally different model of trading costs to look at the effect of the opening of the Hong Kong Shanghai Connect that links the stock exchanges in the two cities, arguably the biggest event in international business and finance since ... More
David vs Goliath (You against the Markets), A Dynamic Programming Approach to Separate the Impact and Timing of Trading CostsMar 03 2016May 31 2016To trade, or not to trade, that is the question Whether an optimizer can yield the answer Against the spikes and crashes of markets gone wild. To quench one's thirst before liquidity runs dry Or wait till the tide of momentum turns mild. A trader's conundrum ... More
Securities Lending Strategies, Valuation of Term Loans using Option TheorySep 06 2016Nov 06 2016We develop models to price long term loans in the securities lending business. These longer horizon deals can be viewed as contracts with optionality embedded in them and can be priced using established methods from derivatives theory, becoming to our ... More
Solving the Equity Risk Premium Puzzle and Inching Towards a Theory of EverythingApr 17 2016May 31 2016The equity risk premium puzzle is that the return on equities has far exceeded the average return on short-term risk-free debt and cannot be explained by conventional representative-agent consumption based equilibrium models. We review a few attempts ... More
A sharp isoperimetric bound for convex bodiesOct 31 2004We consider the problem of lower bounding a generalized Minkowski measure of subsets of a convex body with a log-concave probability measure, conditioned on the set size. A bound is given in terms of diameter and set size, which is sharp for all set sizes, ... More
Infinitely ramified Galois representationsMar 01 2000In this paper we show how to construct, for most p >= 5, two types of surjective representations \rho:G_Q=Gal(\bar{Q}/Q) -> GL_2(Z_p) that are ramified at an infinite number of primes. The image of inertia at almost all of these primes will be torsion-free. ... More
Observing the CMB with the AMiBAJul 19 2001I discuss the capabilities and limitations of the AMiBA for imaging CMB anisotropies. Michael Kesteven (ATNF-CSIRO) has proposed drift-scanning as an observing strategy for measuring and rejecting any instrumental response that the close-packed interferometers ... More
Twelve points on the projective line, branched covers, and rational elliptic fibrationsOct 14 1999The following divisors in the space Sym^{12} P^1 of twelve points on P^1 are actually the same: (A) the possible locus of the twelve nodal fibers in a rational elliptic fibration (i.e. a pencil of plane cubic curves); (B) degree 12 binary forms that can ... More
Enumerative geometry of plane curves of low genusMar 02 1998We collect various known results (about plane curves and the moduli space of stable maps) to derive new recursive formulas enumerating low genus plane curves of any degree with various behaviors. Recursive formulas are given for the characteristic numbers ... More
Schubert inductionFeb 25 2003Sep 26 2003We describe a Schubert induction theorem, a tool for analyzing intersections on a Grassmannian over an arbitrary base ring. The key ingredient in the proof is the Geometric Littlewood-Richardson rule, described in a companion paper. Schubert problems ... More
The simple random walk and max-degree walk on a directed graphSep 11 2006We show bounds on total variation and $L^{\infty}$ mixing times, spectral gap and magnitudes of the complex valued eigenvalues of a general (non-reversible non-lazy) Markov chain with a minor expansion property. This leads to the first known bounds for ... More
A possible resolution of the CDF psi^prime anomalySep 06 1994We consider the contribution of radially excited 2^3P_{1,2} states to psi^prime production at the Tevatron energy. Production of these states via the conventional gluon fusion mechanism and via gluon and charm quark fragmentation processes is considered. ... More
eta_c production at the Large Hadron ColliderJul 29 2010We have studied the production of the 1S_0 charmonium state, eta_c, at the Large Hadron Collider (LHC) in the framework of Non-Relativistic Quantum Chromodynamics (NRQCD) using heavy-quark symmetry. We find that NRQCD predicts a large production cross-section ... More
Correlations among the Riemann zeros: Invariance, resurgence, prophecy and self-dualityMay 25 2004Jun 02 2004We present a conjecture describing new long range correlations among the Riemann zeros leading to 3 principal features: (i) The spectral auto-correlation is invariant w.r.t. the averaging window. (ii) Resurgence occurs wherein the lowest zeros appear ... More
Bumblebees minimize control challenges by combining active and passive modes in unsteady windsMar 01 2016Mar 02 2016The natural wind environment that volant insects encounter is unsteady and highly complex, posing significant flight control and stability challenges. Unsteady airflows can range from structured chains of discrete vortices shed in the wake of an object ... More
The shear dynamo problem for small magnetic Reynolds numbersOct 12 2009Sep 01 2010We study large-scale dynamo action due to turbulence in the presence of a linear shear flow, in the low conductivity limit. Our treatment is nonperturbative in the shear strength and makes systematic use of both the shearing coordinate transformation ... More
A Patterns Based Approach for Design of Educational TechnologiesFeb 07 2018Instructional design is a fundamental base for educational technologies as it lays the foundation to facilitate learning and teaching based on pedagogical underpinnings. However, most of the educational technologies today face two core challenges in this ... More
Effect of stretching-induced changes in hydrodynamic screening on coil-stretch hysteresis of unentangled polymer solutionsSep 07 2016Extensional rheometry and Brownian Dynamics simulations of flexible polymer solutions confirm predictions based on blob concepts that coil--stretch hysteresis in extensional flows increases with concentration, reaching a maximum at the critical overlap ... More
Universal solvent quality crossover of the zero shear rate viscosity of semidilute DNA solutionsDec 16 2011Dec 19 2013The scaling behaviour of the zero shear rate viscosity of semidilute unentangled DNA solutions, in the double crossover regime driven by temperature and concentration, is mapped out by systematic experiments. The viscosity is shown to have a power law ... More
NLO-QCD Corrections to Dilepton Production in the Randall-Sundrum ModelJun 16 2005The dilepton production process at hadron colliders in the Randall-Sundrum (RS) model is studied at next-to-leading order in QCD. The NLO-QCD corrections have been computed for the virtual graviton exchange process in the RS model, in addition to the ... More
Finiteness of Selmer groups and deformation ringsNov 01 2002We prove the finiteness of Selmer groups attached to lifts of certain 2-dimensional mod p representations of the absolute Galois group of Q. The mod p representation can be either even or odd. The lifts considered are the ones that were proven to exist ... More
Dependence of Residual Rotation Measure (RRM) on Intervening MgII Absorbers at Cosmic DistancesJul 10 2013We investigate the dependence of residual rotation measure (RRM) on intervening absorption systems at cosmic distances by using a large sample of 539 SDSS quasars in conjunction with the available rotation measure catalog at around 21cm wavelength. We ... More
Local Support Vector Machines:Formulation and AnalysisSep 14 2013We provide a formulation for Local Support Vector Machines (LSVMs) that generalizes previous formulations, and brings out the explicit connections to local polynomial learning used in nonparametric estimation literature. We investigate the simplest type ... More
Saturation of number variance in embedded random matrix ensemblesDec 11 2015We study fluctuation properties of embedded random matrix ensembles of non-interacting particles. For ensemble of two non-interacting particle systems, we find that unlike the spectra of classical random matrices, correlation functions are non-stationary. ... More
The Generalized Poisson distribution and a model of clustering from Poisson initial conditionsMar 05 1998This paper presents a new derivation of the Generalized Poisson distribution. This distribution provides a good fit to the evolved, counts-in-cells distribution measured in numerical simulations of hierarchical clustering from Poisson initial conditions. ... More
Constrained realizations and minimum variance reconstruction of non-Gaussian random fieldsNov 21 1995With appropriate modifications, the Hoffman--Ribak algorithm that constructs constrained realizations of Gaussian random fields having the correct ensemble properties can also be used to construct constrained realizations of those non-Gaussian random ... More
Dependence Balance Based Outer Bounds for Gaussian Networks with Cooperation and FeedbackDec 10 2008Dec 19 2008We obtain new outer bounds on the capacity regions of the two-user multiple access channel with generalized feedback (MAC-GF) and the two-user interference channel with generalized feedback (IC-GF). These outer bounds are based on the idea of dependence ... More
The Chow ring of the moduli space of curves of genus 6Jul 25 2013We determine the Chow ring (with Q-coefficients) of M_6 by showing that all Chow classes are tautological. In particular, all algebraic cohomology is tautological, and the natural map from Chow to cohomology is injective. To demonstrate the utility of ... More
On the K-theory of schemes with group scheme actionsSep 17 2015We prove some fundamental results like localization, excision, Nisnevich descent and the Mayer-Vietoris property for equivariant regular blow-up for the equivariant K-theory of schemes with an affine group scheme action. We also show that the equivariant ... More
Why Transactional Memory Should Not Be Obstruction-FreeFeb 09 2015Mar 04 2016Transactional memory (TM) is an inherently optimistic abstraction: it allows concurrent processes to execute sequences of shared-data accesses (transactions) speculatively, with an option of aborting them in the future. Early TM designs avoided using ... More
On the Cost of Concurrency in Transactional MemoryMar 07 2011Jun 27 2013The crux of software transactional memory (STM) is to combine an easy-to-use programming interface with an efficient utilization of the concurrent-computing abilities provided by modern machines. But does this combination come with an inherent cost? We ... More
The Query-commit ProblemOct 05 2011In the query-commit problem we are given a graph where edges have distinct probabilities of existing. It is possible to query the edges of the graph, and if the queried edge exists then its endpoints are irrevocably matched. The goal is to find a querying ... More
Geometry of Online Packing Linear ProgramsApr 26 2012We consider packing LP's with $m$ rows where all constraint coefficients are normalized to be in the unit interval. The n columns arrive in random order and the goal is to set the corresponding decision variables irrevocably when they arrive so as to ... More
Duality between quantum and classical dynamics for integrable billiardsJan 10 2006We establish a duality between the quantum wave vector spectrum and the eigenmodes of the classical Liouvillian dynamics for integrable billiards. Signatures of the classical eigenmodes appear as peaks in the correlation function of the quantum wave vector ... More
Fractal Weyl laws for chaotic open systemsAug 13 2002May 30 2003We present a result relating the density of quantum resonances for an open chaotic system to the fractal dimension of the associated classical repeller. The result is supported by numerical computation of the resonances of the system of n disks on a plane. ... More
Explaining Anomalous CDF mu gamma Missing-E_T Events With SupersymmetryNov 01 2001May 22 2002CDF recently reported an excess of events in the mu-gamma-missing E_T channel that disagrees with the Standard Model prediction. No such excess was observed in the e-gamma-mett channel. We explain the excess via resonant smuon production with a single ... More
Probing Large Extra Dimensions Using Top Production in Photon-Photon CollisionsMay 19 1999Jul 12 1999Theories with large extra dimensions predict an infinite tower of Kaluza-Klein states in the 1 TeV range, which can consequently have significant implications for experimental observables. One such observable, which gets affected by the exchange of spin-2 ... More
eta_c Production at the Tevatron: A test of NRQCDMar 23 1998Aug 11 1998We use NRQCD to predict the cross section for $\eta_c$ production at the Tevatron. The non-perturbative matrix elements required are obtained, using heavy-quark symmetry, from the matrix elements determined from the CDF $J/\psi$ data. Our numbers are, ... More
Geometry of two-qubit states with negative conditional entropySep 14 2016We review the geometric features of negative conditional entropy and the properties of the conditional amplitude operator proposed by Cerf and Adami for two qubit states in comparison with entanglement and nonlocality of the states. We identify the region ... More
Transverse structure function in the factorisation methodJul 22 1996Aug 08 1996Deep Inelastic scattering experiments using transversely polarised targets yield information on the structure function $g_2$. By means of a free-field analysis, we study the operator structure of $g_2$ and demonstrate the need for retaining the twist ... More
Structure and Interpretation of Computer ProgramsMar 27 2008Call graphs depict the static, caller-callee relation between "functions" in a program. With most source/target languages supporting functions as the primitive unit of composition, call graphs naturally form the fundamental control flow representation ... More
Resonant slepton production at the LHC in models with an ultralight gravitinoNov 20 2003Mar 12 2004We examine resonant slepton production at the LHC with gravitinos in the final state. The slepton undergoes gauge decay into a neutralino and a lepton, the neutralino decays into a photon and a gravitino. By measuring the transverse masses of the gamma- ... More
Non-linear microwave impedance of short and long Josephson JunctionsOct 26 1998The non-linear dependence on applied $ac$ field ($b_{\omega}$) or current ($% i_{\omega}$) of the microwave (ac) impedance $R_{\omega}+iX_{\omega}$ of both short and long Josephson junctions is calculated under a variety of excitation conditions. The ... More
Unstable $m=1$ modes of counter-rotating Keplerian discsMar 10 2012We study the linear $m=1$ counter-rotating instability in a two-component, nearly Keplerian disc. Our goal is to understand these \emph{slow} modes in discs orbiting massive black holes in galactic nuclei. They are of interest not only because they are ... More
J/psi+gamma production at the LHCJan 12 1999May 03 1999The associated production of J/psi + gamma at the LHC is studied within the NRQCD framework. The signal we focus on is the production of a J/psi and an isolated photon produced back-to-back, with their transverse momenta balanced. It is shown that even ... More
Associated production of a Kaluza-Klein excitation of a gluon with a t t(bar) pair at the LHCOct 11 2007In Randall-Sundrum models, the Kaluza-Klein (KK) excitations of the gluon, g_{KK} have enhanced couplings to the right-handed quarks. In the absence of a gg g_{KK} coupling in these models, the single production of a g_{KK} from an initial gg state is ... More
Tevatron constraint on the Kaluza-Klein gluon of the Bulk Randall-Sundrum modelMar 06 2007The Bulk Randall-Sundrum model, where all Standard Model particles except the Higgs are free to propagate in the bulk, predicts the existence of Kaluza-Klein (KK) modes of the gluon with a large branching into top-antitop pairs. We study the production ... More
Non-perturbative unification in the light of LEP resultsJun 14 1993We consider an alternative to conventional GUTs originally proposed by Maiani, Parisi and Petronzio, where owing to the existence of extra fermion generations at some intermediate scale, the gauge couplings become large at high energies. We first comment ... More
Chi-squared Amplification: Identifying Hidden HubsAug 12 2016Nov 16 2016We consider the following general hidden hubs model: an $n \times n$ random matrix $A$ with a subset $S$ of $k$ special rows (hubs): entries in rows outside $S$ are generated from the probability distribution $p_0 \sim N(0,\sigma_0^2)$; for each row in ... More
Proton-proton fusion in lattice effective field theoryNov 10 2014The proton-proton fusion rate is calculated at low energy in a lattice effective field theory (EFT) formulation. The strong and the Coulomb interactions are treated non-perturbatively at leading order in the EFT. The lattice results are shown to accurately ... More
Semi-Automated SVG Programming via Direct ManipulationAug 09 2016Direct manipulation interfaces provide intuitive and interactive features to a broad range of users, but they often exhibit two limitations: the built-in features cannot possibly cover all use cases, and the internal representation of the content is not ... More
A natural smooth compactification of the space of elliptic curves in projective spaceJul 14 2006The space of smooth genus 0 curves in projective space has a natural smooth compactification: the moduli space of stable maps, which may be seen as the generalization of the classical space of complete conics. In arbitrary genus, no such natural smooth ... More
Outer Bounds for Multiple Access Channels with Feedback using Dependence BalanceMay 31 2008We use the idea of dependence balance to obtain a new outer bound for the capacity region of the discrete memoryless multiple access channel with noiseless feedback (MAC-FB). We consider a binary additive noisy MAC-FB whose feedback capacity is not known. ... More
The genesis of morphologies in extended radio sources: X-shapes, off-axis distortions and giant radio sourcesNov 12 2008We examine relationships between the morphology in double radio sources and the radio-optical position angle offset--the relative orientation of the radio axis with respect to the major axis of the host galaxy. The study was done for a representative ... More
Progressive Transactional Memory in Time and SpaceFeb 17 2015Nov 13 2015Transactional memory (TM) allows concurrent processes to organize sequences of operations on shared \emph{data items} into atomic transactions. A transaction may commit, in which case it appears to have executed sequentially or it may \emph{abort}, in ... More