Results for "Thomas Dandekar"

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Towards Design and Implementation of a Language Technology based Information Processor for PDM SystemsAug 08 2010Product Data Management (PDM) aims to provide 'Systems' contributing in industries by electronically maintaining organizational data, improving data repository system, facilitating with easy access to CAD and providing additional information engineering ... More
Optimizing defence, counter-defence and counter-counter defence in parasitic and trophic interactions -- A modelling studyJul 10 2019In host-pathogen interactions, often the host (attacked organism) defends itself by some toxic compound and the parasite, in turn, responds by producing an enzyme that inactivates that compound. In some cases, the host can respond by producing an inhibitor ... More
Non-power-law relaxation in A-B annihilation with exclusionFeb 17 2016We explore the effect of initial conditions on the decay of the reaction $A+B \rightarrow \phi$ in one dimension, with exclusion interaction between particles. It is well-known that the late-time density of surviving particles goes as $t^{-1/4}$ with ... More
Proportionate growth in patterns formed in the rotor-router modelDec 24 2013We study the growing patterns in the rotor-router model formed by adding $N$ walkers at the center of a $L \times L$ two-dimensional square lattice, starting with a periodic background of arrows, and relaxing to a stable configuration. The pattern is ... More
A class of exactly solved assisted hopping models of active-absorbing state transitions on a lineJun 14 2013Jun 20 2013We construct a class of assisted hopping models in one dimension in which a particle can move only if it does not lie in an otherwise empty interval of length greater than $n+1$. We determine the exact steady state by a mapping to a gas of defects with ... More
Experimental Evaluation of a Reconfigurable Antenna System for Blind Interference AlignmentMar 29 2016In recent years, several experimental studies have come out to validate the theoretical findings of interference alignment (IA), but only a handful of studies have focused on blind interference alignment. Unlike IA and other interference mitigation techniques, ... More
Hierarchical Lattice Models of Hydrogen Bond Networks in WaterSep 25 2017Jun 18 2018We develop a graph-based model of the hydrogen bond network in water, with a view towards quantitatively modeling the molecular-level correlational structure of the network. The networks are formed are studied by the constructing the model on two infinite-dimensional ... More
Biased Assimilation, Homophily and the Dynamics of PolarizationSep 26 2012Are we as a society getting more polarized, and if so, why? We try to answer this question through a model of opinion formation. Empirical studies have shown that homophily results in polarization. However, we show that DeGroot's well-known model of opinion ... More
Privacy Auctions for Recommender SystemsNov 11 2011Sep 27 2012We study a market for private data in which a data analyst publicly releases a statistic over a database of private information. Individuals that own the data incur a cost for their loss of privacy proportional to the differential privacy guarantee given ... More
Learning Sequential Channel Selection for Interference Alignment using Reconfigurable AntennasDec 17 2017Feb 12 2019In recent years, machine learning techniques have been explored to support, enhance or augment wireless systems especially at the physical layer of the protocol stack. Traditional ML based approach or optimization is often not suitable due to algorithmic ... More
Black holes in presence of cosmological constant: Second order in 1/DMay 01 2018Jul 03 2018We have extended the results of arXiv:1704.06076 upto second subleading order in an expansion around large dimension D. Unlike the previous case, there are non-trivial metric corrections at this order. Due to our `background-covariant' formalism, the ... More
Analysis and Augmented Spatial Processing for Uplink OFDMA MU-MIMO Receiver with Transceiver I/Q Imbalance and External InterferenceJul 02 2014Feb 25 2016We address receiver (RX) signal processing in MIMO systems under in-phase/quadrature (I/Q) imbalance, which causes cross-talk of mirror-subcarriers in OFDM systems. We extend the typically reported single-user studies to uplink OFDMA-based multiuser MIMO, ... More
Unstable `black branes' from scaled membranes at large $D$Sep 09 2016It has recently been demonstrated that the dynamics of black holes at large $D$ can be recast as a set of non gravitational membrane equations. These membrane equations admit a simple static solution with shape $S^{D-p-2} \times R^{p,1}$. In this note ... More
The large D black hole Membrane Paradigm at first subleading orderJul 21 2016Aug 23 2016In the large D limit, and under certain circumstances, it has recently been demonstrated that black hole dynamics in asymptotically flat spacetime reduces to the dynamics of a non gravitational membrane propagating in flat D dimensional spacetime. We ... More
ALOHA With Collision Resolution(ALOHA-CR): Theory and Software Defined Radio ImplementationSep 16 2009A cross-layer scheme, namely ALOHA With Collision Resolution (ALOHA-CR), is proposed for high throughput wireless communications in a cellular scenario. Transmissions occur in a time-slotted ALOHA-type fashion but with an important difference: simultaneous ... More
FPGA Implementation of a Scalable and Run-Time Adaptable Multi-Standard Packet DetectorSep 14 2016This paper describes a step by step approach for implementing a scalable and run-time adaptable multi-standard packet detector for orthogonal frequency divisional multiplexing (OFDM) based communication standards. The paper briefly describes considerations ... More
The large D black hole Membrane Paradigm at first subleading orderJul 21 2016Nov 21 2016In the large D limit, and under certain circumstances, it has recently been demonstrated that black hole dynamics in asymptotically flat spacetime reduces to the dynamics of a non gravitational membrane propagating in flat D dimensional spacetime. We ... More
Liquidity in Credit Networks: A Little Trust Goes a Long WayJul 03 2010Feb 20 2012Credit networks represent a way of modeling trust between entities in a network. Nodes in the network print their own currency and trust each other for a certain amount of each other's currency. This allows the network to serve as a decentralized payment ... More
Unstable `black branes' from scaled membranes at large $D$Sep 09 2016Nov 25 2016It has recently been demonstrated that the dynamics of black holes at large $D$ can be recast as a set of non gravitational membrane equations. These membrane equations admit a simple static solution with shape $S^{D-p-2} \times R^{p,1}$. In this note ... More
The large D black hole dynamics in AdS/dS backgroundsApr 20 2017May 01 2018We have constructed a class of perturbative dynamical black hole solutions in presence of cosmological constant. We have done our calculation in large number of dimensions. The inverse power of dimension has been used as the perturbation parameter and ... More
An Action for and Hydrodynamics from the improved Large D membraneDec 26 2017Jul 31 2018It has recently been demonstrated that black hole dynamics at large D is dual to the motion of a probe membrane propagating in the background of a spacetime that solves Einstein's equations. The equation of motion of this membrane is determined by the ... More
On the quantifier-free dynamic complexity of ReachabilityJun 13 2013Jan 28 2015The dynamic complexity of the reachability query is studied in the dynamic complexity framework of Patnaik and Immerman, restricted to quantifier-free update formulas. It is shown that, with this restriction, the reachability query cannot be dynamically ... More
Sélection de la structure d'un perceptron multicouches pour la réduction dun modèle de simulation d'une scierieDec 05 2008Simulation is often used to evaluate the relevance of a Directing Program of Production (PDP) or to evaluate its impact on detailed sc\'enarii of scheduling. Within this framework, we propose to reduce the complexity of a model of simulation by exploiting ... More
Infinite reduced words and the Tits boundary of a Coxeter groupJan 05 2013Sep 18 2014Let (W,S) be a finite rank Coxeter system with W infinite. We prove that the limit weak order on the blocks of infinite reduced words of W is encoded by the topology of the Tits boundary of the Davis complex X of W. We consider many special cases, including ... More
On the boundedness of an iteration involving points on the hypersphereJan 11 2010Oct 05 2010For a finite set of points $X$ on the unit hypersphere in $\mathbb{R}^d$ we consider the iteration $u_{i+1}=u_i+\chi_i$, where $\chi_i$ is the point of $X$ farthest from $u_i$. Restricting to the case where the origin is contained in the convex hull of ... More
Causes and Explanations in the Structural-Model Approach: Tractable CasesDec 12 2012In this paper, we continue our research on the algorithmic aspects of Halpern and Pearl's causes and explanations in the structural-model approach. To this end, we present new characterizations of weak causes for certain classes of causal models, which ... More
Dynamic Conjunctive QueriesApr 05 2017The article investigates classes of queries maintainable by conjunctive queries (CQs) and their extensions and restrictions in the dynamic complexity framework of Patnaik and Immerman. Starting from the basic language of quantifier-free conjunctions of ... More
Nef reduction and anticanonical bundlesOct 31 2003We investigate the structure of smooth projective 3-folds X with -K_X nef and K_X^3=0.
How deals with discrete data for the reduction of simulation models using neural networkJun 10 2009Simulation is useful for the evaluation of a Master Production/distribution Schedule (MPS). Also, the goal of this paper is the study of the design of a simulation model by reducing its complexity. According to theory of constraints, we want to build ... More
An optimization principle for the computation of MHD equilibria in the solar coronaDec 21 2006AIMS: We develop an optimization principle for computing stationary MHD equilibria. METHODS: Our code for the self-consistent computation of the coronal magnetic fields and the coronal plasma uses non-force-free MHD equilibria. Previous versions of the ... More
Probabilistic Reasoning about Actions in Nonmonotonic Causal TheoriesOct 19 2012We present the language {m P}{cal C}+ for probabilistic reasoning about actions, which is a generalization of the action language {cal C}+ that allows to deal with probabilistic as well as nondeterministic effects of actions. We define a formal semantics ... More
Elagage d'un perceptron multicouches : utilisation de l'analyse de la variance de la sensibilité des paramètresDec 04 2008The stucture determination of a neural network for the modelisation of a system remain the core of the problem. Within this framework, we propose a pruning algorithm of the network based on the use of the analysis of the sensitivity of the variance of ... More
Two-Variable Logic with Two Order RelationsOct 07 2011Mar 03 2012It is shown that the finite satisfiability problem for two-variable logic over structures with one total preorder relation, its induced successor relation, one linear order relation and some further unary relations is EXPSPACE-complete. Actually, EXPSPACE-completeness ... More
Spectral Correlations in the Crossover Transition from a Superposition of Harmonic Oscillators to the Gaussian Unitary EnsembleJul 20 1998We compute the spectral correlation functions for the transition from a harmonic oscillator towards the Gaussian Unitary Ensemble (GUE). We use a variant of the supersymmetry method to obtain analytical results in a fast and elegant way. In contrast to ... More
Thermodynamic formalism for transport coefficients with an application to the shear modulus and shear viscosityDec 07 2016We discuss Onsager's thermodynamic formalism for transport coefficients and apply it to the calculation of the shear modulus and shear viscosity of a monodisperse system of repulsive particles. We focus on the concept of extensive "distance" and intensive ... More
GAVO Tools for the Analysis of Stars and NebulaeJun 15 2007Within the framework of the German Astrophysical Virtual Observatory (GAVO), we provide synthetic spectra, simulation software for the calculation of NLTE model atmospheres, as well as necessary atomic data. This will enable a VO user to directly compare ... More
Finite group extensions and the Baum-Connes conjectureSep 13 2002Jul 29 2007In this note, we exhibit a method to prove the Baum-Connes conjecture (with coefficients) for extensions with finite quotients of certain groups which already satisfy the Baum-Connes conjecture. Interesting examples to which this method applies are torsion-free ... More
Quantization and the Issue of Time for Various Two-Dimensional Models of GravityAug 31 1993It is shown that the models of 2D Liouville Gravity, 2D Black Hole- and $R^2$-Gravity are {\em embedded} in the Katanaev-Volovich model of 2D NonEinsteinian Gravity. Different approaches to the formulation of a quantum theory for the above systems are ... More
Measuring the Accuracy of Linked Data IndicesMar 19 2016Being based on Web technologies, Linked Data is distributed and decentralised in its nature. Hence, for the purpose of finding relevant Linked Data on the Web, search indices play an important role. Also for avoiding network communication overhead and ... More
Modelling Epidemics on NetworksNov 21 2011Dec 15 2011Infectious disease remains, despite centuries of work to control and mitigate its effects, a major problem facing humanity. This paper reviews the mathematical modelling of infectious disease epidemics on networks, starting from the simplest Erdos-Renyi ... More
Anomalies and large N limits in matrix string theoryJun 20 1998May 13 1999We study the loop expansion for the low energy effective action for matrix string theory. For long string configurations we find the result depends on the ordering of limits. Taking $g_s\to 0$ before $N\to\infty$ we find free strings. Reversing the order ... More
Generalised network clustering and its dynamical implicationsJun 23 2010A parameterisation of generalised network clustering, in the form of four-motif prevalences, is presented. This involves three real parameters that are conditional on one- two- and three-motif prevalences. Interpretations of these real parameters are ... More
Non-Markovian stochastic epidemics in extremely heterogeneous populationsMar 12 2014A feature often observed in epidemiological networks is significant heterogeneity in degree. A popular modelling approach to this has been to consider large populations with highly heterogeneous discrete contact rates. This paper defines an individual-level ... More
Exact epidemic dynamics for generally clustered, complex networksJun 17 2010Oct 02 2012The last few years have seen remarkably fast progress in the understanding of statistics and epidemic dynamics of various clustered networks. This paper considers a class of networks based around a concept (the locale) that allows asymptotically exact ... More
Forbidden Induced SubgraphsOct 15 2016In descending generality I survey: five partial orderings of graphs, the induced-subgraph ordering, and examples like perfect, threshold, and mock threshold graphs. The emphasis is on how the induced subgraph ordering differs from other popular orderings ... More
Tutorial Note on Merging Matrix Elements with Parton ShowersMar 26 2015In this short note, I introduce to essential conceptual features and main building blocks of matrix element merging algorithms, operating on fixed order calculations both at leading order and next-to-leading order. The intention is purely pedagogical, ... More
Measured geodesic laminations in FlatlandJan 16 2015Since their introduction by Thurston, measured geodesic laminations on hyperbolic surfaces occur in many contexts. In this survey, we give a generalization of geodesic laminations on surfaces endowed with a half-translation structure, called flat laminations, ... More
Decompositions of Binomial Ideals in Macaulay 2Jun 29 2011The package Binomials contains implementations of specialized algorithms for binomial ideals, including primary decomposition into binomial ideals. The current implementation works in characteristic zero. Primary decomposition is restricted to binomial ... More
A new formula for $ζ$(2n + 1) (and how not to prove that $ζ$(5) is irrational)Aug 09 2016Using a new polylogarithmic identity, we express the values of $\zeta$ at odd integers 2n + 1 as integrals over unit n--dimensional hypercubes of simple functions involving products of logarithms. We then make several conjectures, based on numerical evidence, ... More
The Cornstarch FlamethrowerJun 06 2016Igniting cornstarch powder is a classic physics demonstration that showcases the rapid conduction of heat for a material in which the surface area is greater than the volume of its constituent particles. Including such a demonstration in a physics "magic ... More
Strong solidity of group factors from lattices in SO(n,1) and SU(n,1)Sep 12 2010We show that the group factors of ICC lattices in either SO(n,1) or SU(n,1), n \geq 2, are strongly solid in the sense of Ozawa and Popa. This strengthens a result of Ozawa and Popa showing that these factors do not have Cartan subalgebras.
Periodic excitations of bilinear quantum systemsMar 06 2011Aug 09 2012A well-known method of transferring the population of a quantum system from an eigenspace of the free Hamiltonian to another is to use a periodic control law with an angular frequency equal to the difference of the eigenvalues. For finite dimensional ... More
The obstruction to the existence of a loopless star productSep 30 2013Jan 15 2014We show that there is an obstruction to the existence of a star product defined by Kontsevich graphs without directed cycles.
Characteristic classes in deformation quantizationAug 21 2012Dec 03 2014In deformation quantization one can associate five characteristic functions to (stable) formality morphisms on cochains and chains and to "two-brane" formality morphisms. We show that these characteristic functions agree.
Probabilistic Latent Semantic AnalysisJan 23 2013Probabilistic Latent Semantic Analysis is a novel statistical technique for the analysis of two-mode and co-occurrence data, which has applications in information retrieval and filtering, natural language processing, machine learning from text, and in ... More
Testing Quarkonium Production with Photoproduced $J/ψ+ γ$Nov 13 1996Jan 14 1997I compute the leading color-octet contributions to the process $\gamma + p \to J/\psi + \gamma (+ X)$ within the non-relativistic QCD (NRQCD) factorization formalism. In the color-singlet model, $J/\psi + \gamma$ can only be produced when the photon interacts ... More
Summing $O(β_0^n α_s^{n+1})$ Corrections to Top Quark DecaysJul 21 1997Order $\beta_0^n \alpha_s^{n+1}$ QCD corrections to top quark decays into $W^+$ and $H^+$ bosons are computed to all orders in perturbation theory. Predictions for the radiative corrections to the top quark width are compared with the estimates from BLM ... More
The $1/m_Q$ Expansion in QCD: Introduction and OverviewSep 22 1994A mini-review of the heavy mass expansion in QCD is given. We focus on exclusive semileptonic decays and some topics of recent interest in inclusive decays of heavy hadrons.
Computing the Maslov index from singularities of a matrix Riccati equationOct 13 2015Oct 27 2015We study the Maslov index as a tool to analyze stability of steady state solutions to a reaction-diffusion equation in one spatial dimension. We show that the path of unstable subspaces associated to this equation is governed by a matrix Riccati equation ... More
Constrained randomization of time series dataSep 30 1999A new method is introduced to create artificial time sequences that fulfil given constraints but are random otherwise. Constraints are usually derived from a measured signal for which surrogate data are to be generated. They are fulfilled by minimizing ... More
Genealogy of Nonperturbative Quantum-Invariants of 3-Manifolds: The Surgical FamilyJan 21 1996Mar 22 1996We study the relations between the invariants $\tau_{RT}$, $\tau_{HKR}$, and $\tau_L$ of Reshetikhin-Turaev, Hennings-Kauffman-Radford, and Lyubashenko, respectively. In particular, we discuss explicitly how $\tau_L$ specializes to $\tau_{RT}$ for semisimple ... More
Mapping Class Group Actions on Quantum DoublesFeb 03 1994We study representations of the mapping class group of the punctured torus on the double of a finite dimensional possibly non-semisimple Hopf algebra that arise in the construction of universal, extended topological field theories. We discuss how for ... More
An introduction to Differential Linear Logic: proof-nets, models and antiderivativesJun 06 2016Differential Linear Logic enriches Linear Logic with additional logical rules for the exponential connectives, dual to the usual rules of dereliction, weakening and contraction. We present a proof-net syntax for Differential Linear Logic and a categorical ... More
A statistical physics perspective on criticality in financial marketsOct 09 2013Jan 27 2014Stock markets are complex systems exhibiting collective phenomena and particular features such as synchronization, fluctuations distributed as power-laws, non-random structures and similarity to neural networks. Such specific properties suggest that markets ... More
Statistical pairwise interaction model of stock marketJun 20 2012Jan 27 2014Financial markets are a classical example of complex systems as they comprise many interacting stocks. As such, we can obtain a surprisingly good description of their structure by making the rough simplification of binary daily returns. Spin glass models ... More
Invasion-wave induced first-order phase transition in systems of active particlesMar 31 2013An Enskog-like kinetic equation for self-propelled particles is solved numerically. I study a density instability near the transition to collective motion and find that while hydrodynamics breaks down, the kinetic approach leads to soliton-like supersonic ... More
Continuum Study of Heavy Quark DiffusionApr 28 2015We report on a lattice investigation of heavy quark momentum diffusion within the pure SU(3) plasma above the deconfinement transition with the quarks treated to leading order in the heavy mass expansion. We measure the relevant "colour-electric" Euclidean ... More
Sources of false positives and false negatives in the STATCHECK algorithm: Reply to Nuijten et al. (2015)Oct 04 2016Oct 10 2016STATCHECK is an R algorithm designed to scan papers automatically for inconsistencies between test statistics and their associated p values (Nuijten et al., 2015). The goal of this comment is to point out an important and well-documented flaw in this ... More
Telling Breaking News Stories from Wikipedia with Social Multimedia: A Case Study of the 2014 Winter OlympicsMar 17 2014With the ability to watch Wikipedia and Wikidata edits in realtime, the online encyclopedia and the knowledge base have become increasingly used targets of research for the detection of breaking news events. In this paper, we present a case study of the ... More
Guaranteed successful strategies for a square achievement game on an n by n gridSep 11 2011May 20 2012At some places (see the references) Martin Erickson describes a certain game: "Two players alternately write O's (first player) and X's (second player) in the unoccupied cells of an n x n grid. The first player (if any) to occupy four cells at the vertices ... More
Finite-size scaling tests for SU(3) lattice gauge theory with color sextet fermionsOct 16 2009The observed slow running of the gauge coupling in SU(3) lattice gauge theory with two flavors of color sextet fermions naturally suggests it is a theory with one relevant coupling, the fermion mass, and that at zero mass correlation functions decay algebraically. ... More
Volume scaling of Dirac eigenvalues in SU(3) lattice gauge theory with color sextet fermionsJun 24 2009I observe a rough volume-dependent scaling of the low eigenvalues of a chiral Dirac operator in lattice studies of SU(3) lattice gauge theory with two flavors of color sextet fermions, in its weak-coupling phase. The mean value of the ith eigenvalue scales ... More
Reweighting QCD simulations with dynamical overlap fermionsOct 03 2008I apply a recently developed algorithm for reweighting simulations of lattice QCD from one quark mass to another to simulations performed with overlap fermions in the epsilon regime. I test it by computing the condensate from distributions of the low ... More
Eigenvalue Decomposition of Meson CorrelatorsOct 27 2003Euclidean space hadronic correlators are computed in quenched QCD at small quark mass using truncations of quark propagators which include or exclude low eigenvalue eigenmodes of the Dirac operator. High modes provide the dominant contribution to parity ... More
Kaon B Parameter in Quenched QCDSep 08 2003I calculate the kaon B-parameter with a lattice simulation in quenched approximation. The lattice simulation uses an action possessing exact lattice chiral symmetry, an overlap action. Computations are performed at two lattice spacings, about 0.13 and ... More
Short distance current correlators: Comparing lattice simulations to the instanton liquidJun 01 2001Aug 01 2001Point to point correlators of currents are computed in quenched QCD using a chiral lattice fermion action, the overlap action. I compare correlators made of exact quark propagators with correlators restricted to low (less than 500 MeV) eigenvalue eigenmodes ... More
Oblique correction in a walking lattice theoryJun 18 2010I compute the difference of vector and axial vector current correlators in the weak coupling phase of (lattice-regulated) SU(3) gauge theory with two flavors of symmetric-representation dynamical fermions. This is a walking theory at the bare parameter ... More
Ginsparg-Wilson GamesAug 23 1999I implement a set of tricks for constructing lattice fermion actions which approximately realize the Ginsparg-Wilson relation, with very promising results from simulations.
Sources of false positives and false negatives in the STATCHECK algorithm: Reply to Nuijten et al. (2016)Oct 04 2016Nov 15 2016STATCHECK is an R algorithm designed to scan papers automatically for inconsistencies between test statistics and their associated p values (Nuijten et al., 2016). The goal of this comment is to point out an important and well-documented flaw in this ... More
Spectroscopic madness--A golden age for amateursJan 04 2011Today, professional instrumentation is dominated by heavily oversubscribed telescopes which focus mainly on a limited number of "fashionable" research topics. As a result, time acquisition for massive star research, including extended observation campaigns, ... More
Generalized guidance equation for peaked quantum solitons: the single particle caseFeb 09 2016We study certain non-linear generalisations of the Schr{\"o}dinger equation which admit static solitonic 2 solutions in absence of external potential acting on the particle. We consider a class of solutions that can be written as a product of a solution ... More
Generalized guidance equation for peaked quantum solitons and effective gravityFeb 11 2016Apr 12 2016Bouncing oil droplets have been shown to follow de Broglie-Bohm like trajectories and at the same time they exhibit attractive and repulsive pseudo-gravitation. We propose a model aimed at rendering account of these phenomenological observations. It inspires, ... More
Finite-size scaling tests for spectra in SU(3) lattice gauge theory coupled to 12 fundamental flavor fermionsSep 06 2011I carry out a finite-size scaling study of the correlation length in SU(3) lattice gauge theory coupled to 12 fundamental flavor fermions, using recent data published by Fodor, Holland, Kuti, Nogradi and Schroeder. I make the assumption that the system ... More
KPP reaction-diffusion systems with loss inside a cylinder: convergence toward the problem with Robin boundary conditionsJul 21 2010We consider in this paper a reaction-diffusion system under a KPP hypothesis in a cylindrical domain in the presence of a shear flow. Such systems arise in predator-prey models as well as in combustion models with heat losses. Similarly to the single ... More
The number of beams in IMRT - theoretical investigations and implications for single-arc IMRTSep 17 2009The first purpose of this paper is to shed some new light on the old question of selecting the number of beams in intensity-modulated radiation therapy (IMRT). The second purpose is to illuminate the related issue of discrete static beam angles vs. rotational ... More
Theoretical Aspects of $b \to s γ$ TransitionsMar 29 2001Apr 25 2001In this talk some of the theoretical aspects of $b \to s \gamma$ transitions are discussed. The focus is on inclusive decays, since these can be computed more reliably. Topics covered are (1) perturbative QCD corrections, (2) non-perturbative contributions ... More
A sharp bilinear cone restriction estimateMay 01 2001The purpose of this paper is to prove an essentially sharp L^2 Fourier restriction estimate for light cones, of the type which is called bilinear in the recent literature.
Physics at ELSA, achievements and futureJan 24 2005At ELSA interesting results on baryon resonances have been obtained by the CB-ELSA, the CBELSA/TAPS and the SAPHIR collaborations. New resonances were found, in particular a new $\rm D_{15}(2070)$ decaying into $p\eta$, was recently observed by the CB-ELSA ... More
The search for missing baryon resonancesJan 11 2005Experiments with electromagnetic probes are promising to search for baryon resonances that have been predicted by quark models but have not yet been observed. Data sets from different experiments show interesting resonance structures possibly due to so ... More
Low-Prandtl-number Bénard-Marangoni convection in a vertical magnetic fieldJun 30 2009The effect of a homogeneous magnetic field on surface-tension-driven B\'{e}nard convection is studied by means of direct numerical simulations. The flow is computed in a rectangular domain with periodic horizontal boundary conditions and the free-slip ... More
Critical Wilson Lines in Toroidal Compactifications of Heteroric StringsSep 25 1992Critical values of Wilson lines and general background fields for toroidal compactifications of heterotic string theories are constructed systematically using Dynkin diagrams.
On the Spinor Representation of Surfaces in Euclidean 3-SpaceDec 30 1997The aim of the present paper is to clarify the relationship between immersions of surfaces and solutions of the inhomogeneous Dirac equation. The main idea leading to the description of a surface M^2 by a spinor field is the observation that the restriction ... More
Cohomology of the space of commuting n-tuples in a compact Lie groupOct 25 2006Feb 19 2007Consider the space Hom(Z^n,G) of pairwise commuting n-tuples of elements in a compact Lie group G. This forms a real algebraic variety, which is generally singular. In this paper, we construct a desingularization of the generic component of Hom(Z^n,G), ... More
Large ordinalsNov 19 1994Let $j$ be an elementary embedding of $V_{\lambda}$ into $V_{\lambda}$ that is not the identity, and let $\kappa$ be the critical point of $j$. Let $\Cal A$ be the closure of $\{j\}$ under the operation $a (b)$ of application, and let $\Omega$ be the ... More
Descent of coherent sheaves and complexes to geometric invariant theory quotientsJun 27 2002Apr 19 2008Fix a scheme $X$ over a field of characteristic zero that is equipped with an action of a reductive algebraic group $G$. We give necessary and sufficient conditions for a $G$-equivariant coherent sheaf on $X$ or a bounded-above complex of $G$-equivariant ... More
Large Scale Structure in the Local Universe: The 2MASS Galaxy CatalogMay 04 2004Using twin ground-based telescopes, the Two Micron All Sky Survey (2MASS) scanned both equatorial hemi- spheres, detecting more than 500 million stars and resolving more than 1.5 million galaxies in the near-infrared (1 - 2.2 microns) bands. The Extended ... More
The Random Chinese Postman Tour is 4/3-approximate for network searchDec 19 2015Aug 02 2016We consider a classic search problem first proposed by S. Gal in which a Searcher randomizes between unit speed paths on a network, aiming to find a hidden point in minimal expected time in the worst case. This can be viewed as a zero-sum game between ... More
On the breakdown of perturbative integrability in large N matrix modelsJul 21 2005We study the perturbative integrability of the planar sector of a massive SU(N) matrix quantum mechanical theory with global SO(6) invariance and Yang-Mills-like interaction. This model arises as a consistent truncation of maximally supersymmetric Yang-Mills ... More
Conformal Dimensions of Two-Derivative BMN OperatorsJan 21 2003Mar 20 2003We compute the anomalous dimensions of BMN operators with two covariant derivative impurities at the planar level up to first order in the effective coupling lambda'. The result equals those for two scalar impurities as well as for mixed scalar and vector ... More
Graphene and Boron Nitride Single LayersApr 09 2009This Chapter deals with single layers of carbon (graphene) and hexagonal boron nitride on transition metal surfaces. The transition metal substrates take the role of the support and allow due to their catalytic activity the growth of perfect layers by ... More