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Variance-Aware Optimal Power FlowNov 02 2017The incorporation of stochastic loads and generation into the operation of power grids gives rise to an exposure to stochastic risk. This risk has been addressed in prior work through a variety of mechanisms, such as scenario generation or chance constraints, ... More

Learning from power system data stream: phasor-detective approachNov 17 2018Dec 17 2018Assuming access to synchronized stream of Phasor Measurement Unit (PMU) data over a significant portion of a power system interconnect, say controlled by an Independent System Operator (ISO), what can you extract about past, current and future state of ... More

Non-Stationary Streaming PCAFeb 08 2019We consider the problem of streaming principal component analysis (PCA) when the observations are noisy and generated in a non-stationary environment. Given $T$, $p$-dimensional noisy observations sampled from a non-stationary variant of the spiked covariance ... More

Approximation Algorithms for the Incremental Knapsack Problem via Disjunctive ProgrammingNov 18 2013In the incremental knapsack problem ($\IK$), we are given a knapsack whose capacity grows weakly as a function of time. There is a time horizon of $T$ periods and the capacity of the knapsack is $B_t$ in period $t$ for $t = 1, \ldots, T$. We are also ... More

A note on polynomial solvability of the CDT problemJun 25 2014Feb 23 2015We describe a simple polynomial-time algorithm for the CDT problem that relies on a construction of Barvinok.

Optimal adaptive control of cascading power grid failuresDec 17 2010We present theoretical results and experiments with parallel algorithms for computing an adaptive, online control with the objective of attenuating a power grid cascading failure.

The N-K Problem in Power Grids: New Models, Formulations and Numerical Experiments (extended version)Dec 29 2009Dec 31 2009Given a power grid modeled by a network together with equations describing the power flows, power generation and consumption, and the laws of physics, the so-called N-k problem asks whether there exists a set of k or fewer arcs whose removal will cause ... More

Optimizing convex functions over nonconvex setsDec 14 2011In this paper we derive strong linear inequalities for sets of the form {(x, q) \in Rd \times R : q \geq Q(x), x \in Rd - int(P)}, where Q(x) : Rd \rightarrow R is a quadratic function, P \subset Rd and "int" denotes interior. Of particular but not exclusive ... More

LP approximations to mixed-integer polynomial optimization problemsJan 01 2015Oct 19 2016We present a class of linear programming approximations for constrained optimization problems. In the case of mixed-integer polynomial optimization problems, if the intersection graph of the constraints has bounded tree-width our construction yields a ... More

On linear relaxations of OPF problemsNov 05 2014We present lifted linear relaxations of the OPF problem.

Strong NP-hardness of AC power flows feasibilityDec 23 2015We present a rigorous proof of strong NP-hardness of the AC-OPF problem.

Robust Control of Cascading Power Grid Failures using Stochastic ApproximationApr 03 2015Jul 18 2015Cascading failure of a power transmission system are initiated by an exogenous event that disable a set of elements (e.g., lines) followed by a sequence of interrelated failures (or more precisely, trips) of overloaded elements caused by the combination ... More

Models for managing the impact of an epidemicJul 30 2015In this paper we consider robust models for emergency staff deployment in the event of a flu pandemic. We focus on managing critical staff levels at organizations that must remain operational during such an event, and develop methodologies for managing ... More

Chance Constrained Optimal Power Flow: Risk-Aware Network Control under UncertaintySep 25 2012Feb 04 2013When uncontrollable resources fluctuate, Optimum Power Flow (OPF), routinely used by the electric power industry to re-dispatch hourly controllable generation (coal, gas and hydro plants) over control areas of transmission networks, can result in grid ... More

Outer-Product-Free Sets for Polynomial Optimization and Oracle-Based CutsOct 14 2016Cutting planes are derived from specific problem structures, such as a single linear constraint from an integer program. This paper introduces cuts that involve minimal structural assumptions, enabling the generation of strong polyhedral relaxations for ... More

Principled Deep Neural Network Training through Linear ProgrammingOct 07 2018Nov 26 2018Deep Learning has received significant attention due to its impressive performance in many state-of-the-art learning tasks. Unfortunately, while very powerful, Deep Learning is not well understood theoretically and in particular only recently results ... More

Synchronization-Aware and Algorithm-Efficient Chance Constrained Optimal Power FlowJun 12 2013One of the most common control decisions faced by power system operators is the question of how to dispatch generation to meet demand for power. This is a complex optimization problem that includes many nonlinear, non convex constraints as well as inherent ... More

Outer-Product-Free Sets for Polynomial Optimization and Oracle-Based CutsOct 14 2016Nov 03 2016Cutting planes are derived from specific problem structures, such as a single linear constraint from an integer program. This paper introduces cuts that involve minimal structural assumptions, enabling the generation of strong polyhedral relaxations for ... More

Two-sided linear chance constraints and extensionsJul 08 2015Feb 27 2016We examine the convexity and tractability of the two-sided linear chance constraint model under Gaussian uncertainty. We show that these constraints can be applied directly to model a larger class of nonlinear chance constraints as well as provide a reasonable ... More

Outer-Product-Free Sets for Polynomial Optimization and Oracle-Based CutsOct 14 2016Apr 26 2017Cutting planes are derived from specific problem structures, such as a single linear constraint from an integer program. This paper introduces cuts that involve minimal structural assumptions, enabling the generation of strong polyhedral relaxations for ... More

Robust linear control of nonconvex battery operation in transmission systemsOct 29 2016Nov 06 2016We describe a robust multiperiod transmission plan- ning model including renewables and batteries, where battery output is used to partly offset renewable output deviations from forecast. A central element is a nonconvex battery operation model which ... More

Vulnerability Analysis of Power SystemsMar 09 2015Potential vulnerabilities in a power grid can be exposed by identifying those transmission lines on which attacks (in the form of interference with their transmission capabilities) causes maximum disruption to the grid. In this study, we model the grid ... More

Power Grid Vulnerability to Geographically Correlated Failures - Analysis and Control ImplicationsJun 06 2012We consider power line outages in the transmission system of the power grid, and specifically those caused by a natural disaster or a large scale physical attack. In the transmission system, an outage of a line may lead to overload on other lines, thereby ... More

Robust linear control of nonconvex battery operation in transmission systemsOct 29 2016We describe a robust multiperiod transmission plan- ning model including renewables and batteries, where battery output is used to partly offset renewable output deviations from forecast. A central element is a nonconvex battery operation model which ... More

Efficient Synchronization Stability Metrics for Fault ClearingSep 15 2014Direct methods can provide rapid screening of the dynamical security of large numbers fault and contingency scenarios by avoiding extensive time simulation. We introduce a computationally-efficient direct method based on optimization that leverages efficient ... More

Unit Commitment with N-1 Security and Wind UncertaintyJan 30 2016As renewable wind energy penetration rates continue to increase, one of the major challenges facing grid operators is the question of how to control transmission grids in a reliable and a cost-efficient manner. The stochastic nature of wind forces an ... More

Scaling Laws in Self-Gravitating DisksApr 16 1999The interstellar medium (ISM) reveals strongly inhomogeneous structures at every scale. These structures do not seem completely random since they obey certain power laws. Larson's law (\citeyear{Larson81}) $\sigma \propto R^{\delta}$ and the plausible ... More

Casimir force in O(n) lattice models with a diffuse interfaceJun 23 2008On the example of the spherical model we study, as a function of the temperature $T$, the behavior of the Casimir force in O(n) systems with a diffuse interface and slab geometry $\infty^{d-1}\times L$, where $2<d<4$ is the dimensionality of the system. ... More

Fragmentation in Kinematically Cold DisksJan 16 2001Gravity is scale free. Thus gravity may form similar structures in self-gravitating systems on different scales. Indeed, observations of the interstellar medium, spiral disks and cosmic structures, reveal similar characteristics. The structures in these ... More

Extending polynomials in maximal and minimal idealsOct 20 2009Feb 08 2010Given an homogeneous polynomial on a Banach space $E$ belonging to some maximal or minimal polynomial ideal, we consider its iterated extension to an ultrapower of $E$ and prove that this extension remains in the ideal and has the same ideal norm. As ... More

A Field Range Bound for General Single-Field InflationNov 13 2011We explore the consequences of a detection of primordial tensor fluctuations for general single-field models of inflation. Using the effective theory of inflation, we propose a generalization of the Lyth bound. Our bound applies to all single-field models ... More

Formalizing and Checking Thread Refinement for Data-Race-Free Execution Models (Extended Version)Oct 24 2015When optimizing a thread in a concurrent program (either done manually or by the compiler), it must be guaranteed that the resulting thread is a refinement of the original thread. Most theories of valid optimizations are formulated in terms of valid syntactic ... More

The symmetric Radon-Nikodým property for tensor normsMay 15 2010We introduce the symmetric-Radon-Nikod\'ym property (sRN property) for finitely generated s-tensor norms $\beta$ of order $n$ and prove a Lewis type theorem for s-tensor norms with this property. As a consequence, if $\beta$ is a projective s-tensor norm ... More

Signatures of Supersymmetry from the Early UniverseSep 01 2011Oct 11 2011Supersymmetry plays a fundamental role in the radiative stability of many inflationary models. Spontaneous breaking of the symmetry inevitably leads to fields with masses of order the Hubble scale during inflation. When these fields couple to the inflaton ... More

Desensitizing Inflation from the Planck ScaleApr 21 2010A new mechanism to control Planck-scale corrections to the inflationary eta parameter is proposed. A common approach to the eta problem is to impose a shift symmetry on the inflaton field. However, this symmetry has to remain unbroken by Planck-scale ... More

Long-Range Correlations in Self-Gravitating N-Body SystemsJan 29 2002Observed self-gravitating systems reveal often fragmented non-equilibrium structures that feature characteristic long-range correlations. However, models accounting for non-linear structure growth are not always consistent with observations and a better ... More

Lumpy Structures in Self-Gravitating DisksMay 29 2001Following Toomre & Kalnajs (1991), local models of slightly dissipative self-gravitating disks show how inhomogeneous structures can be maintained over several galaxy rotations. Their basic physical ingredients are self-gravity, dissipation and differential ... More

Natural symmetric tensor normsFeb 22 2010Dec 14 2010In the spirit of the work of Grothendieck, we introduce and study natural symmetric n-fold tensor norms. We prove that there are exactly six natural symmetric tensor norms for $n\ge 3$, a noteworthy difference with the 2-fold case in which there are four. ... More

Equilateral Non-Gaussianity and New Physics on the HorizonFeb 25 2011Mar 23 2011We examine the effective theory of single-field inflation in the limit where the scalar perturbations propagate with a small speed of sound. In this case the non-linearly realized time-translation symmetry of the Lagrangian implies large interactions, ... More

Five basic lemmas for symmetric tensor products of normed spacesMay 18 2011We give the symmetric version of five lemmas which are essential for the theory of tensor products (and norms). These are: the approximation, extension, embedding, density and local technique lemmas. Some application of these tools to the metric theory ... More

Tachyons in Classical de Sitter VacuaMar 29 2016We revisit the possibility of de Sitter vacua and slow-roll inflation in type II string theory at the level of the classical two-derivative supergravity approximation. Previous attempts at explicit constructions were plagued by ubiquitous tachyons with ... More

Precision Stellar Astrophysics in the Kepler EraApr 25 2016The study of fundamental properties (such as temperatures, radii, masses, and ages) and interior processes (such as convection and angular momentum transport) of stars has implications on various topics in astrophysics, ranging from the evolution of galaxies ... More

N-Body Simulations of Open, Self-Gravitating SystemsJan 16 2001Astrophysical systems differ often in two points from classical thermodynamical systems: 1.) They are open and 2.) gravity is a dominant factor. Both modifies the homogeneous equilibrium structure, known from classical thermodynamics. In order to study ... More

Null Polarities as Generators of the Projective GroupJun 02 2014It is well-known that the group of regular projective transformations of $\mathbb{P}^3(\mathbb{R})$ is isomorphic to the group of projective automorphisms of Klein's quadric $M_2^4\subset\mathbb{P}^5(\mathbb{R})$. We introduce the Clifford algebra $\mathcal{C}\ell_{(3,3)}$ ... More

A Criticism of "Gas Mode" Reinterpretations of the Michelson-Morley and Similar ExperimentsApr 24 2014It has been argued by R. T. Cahill and others that a Michelson interferometer in "gas mode" - in which the light paths are through an included gaseous medium - are able to detect and have detected an absolute frame of reference. It is shown here that ... More

A Case for Lorentzian RelativityJan 18 2014Mar 06 2015The Lorentz transformation (LT) is explained by changes occurring in the wave characteristics of matter as it changes inertial frame. This explanation is akin to that favoured by Lorentz, but informed by later insights, due primarily to de Broglie, regarding ... More

Syntagma Lexical DatabaseMar 19 2015This paper discusses the structure of Syntagma's Lexical Database (focused on Italian). The basic database consists in four tables. Table Forms contains word inflections, used by the POS-tagger for the identification of input-words. Forms is related to ... More

What is dimensional reduction really telling us?Sep 25 2015Oct 12 2015Numerous approaches to quantum gravity report a reduction in the number of spacetime dimensions at the Planck scale. However, accepting the reality of dimensional reduction also means accepting its consequences, including a variable speed of light. We ... More

Generalized amalgamation and homogeneityMar 31 2016May 05 2016In this paper we shall prove that any $2$-transitive finitely homogeneous structure with a supersimple theory satisfying a generalized amalgamation property is a random structure. In particular, this adapts a result of Koponen for binary homogeneous structures ... More

Towards a Theory of Affect and Software Developers' PerformanceJan 12 2016Jan 23 2016For more than thirty years, it has been claimed that a way to improve software developers' productivity and software quality is to focus on people. The underlying assumption seems to be that "happy and satisfied software developers perform better". More ... More

Logic and linear algebra: an introductionJul 09 2014Aug 24 2015We give an introduction to logic tailored for algebraists, explaining how proofs in linear logic can be viewed as algorithms for constructing morphisms in symmetric closed monoidal categories with additional structure. This is made explicit by showing ... More

Green open access in computer science - an exploratory study on author-based self-archiving awareness, practice, and inhibitorsMay 05 2015Access to the work of others is something that is too often taken for granted, yet problematic and difficult to be obtained unless someone pays for it. Green and gold open access are claimed to be a solution to this problem. While open access is gaining ... More

Meromorphic quotients for some holomorphic G-actionsMay 26 2015Using mainly tools from [B.13] and [B.15] we give a necessary and sufficient condition in order that a holomorphic action of a connected complex Lie group $G$ on a reduced complex space $X$ admits a strongly quasi-proper meromorphic quotient. We apply ... More

Some examples due to H. HironakaJan 06 2015Mar 26 2015The aim of this paper is to explain the construction by H. Hironaka [H.61] of a holomorphic (in fact "algebraic") family of compact complex manifolds parametrized by $\C$ such for all $s \in \C\setminus \{0\}$ the fiber is projective, but such that the ... More

Asymptotics of a vanishing period : characterization of semi-simplicityJan 31 2013In this paper we introduce the word {\em fresco} to denote a monogenic geometric (a,b)-module. This "basic object" (generalized Brieskorn module with one generator) corresponds to the formal germ of the minimal filtered (regular) differential equation. ... More

The theme of a vanishing periodOct 06 2011Let \ $\lambda \in \mathbb{Q}^{*+}$ \ and consider a multivalued formal function of the type $$ \phi(s) : = \sum_{j=0}^k \ c_j(s).s^{\lambda + m_j}.(Log\, s)^j $$ where \ $c_j \in \C[[s]], m_j \in \mathbb{N}$ \ for \ $j \in [0,k-1]$. The {\bf theme} associated ... More

Holomorphic families of $[λ]-$primitive themesAug 12 2015This article is the continuation of [B. 13-b] where we show how the isomorphism class of a $[\lambda]-$primitive theme with a given Bernstein polynomial may be characterized by a (small) finite number of complex parameters. We construct here a corresponding ... More

Algebraic differential equations associated to some polynomialsMay 29 2013Mar 01 2014We compute the Gauss-Manin differential equation for any period of a polynomial in \ $\C[x_{0},\dots, x_{n}]$ \ with \ $(n+2)$ \ monomials. We give two general factorizations theorem in the algebra \ $\C< z, (\frac{\partial}{\partial z})^{-1}>$ \ for ... More

Changements de variable pour un th`eme.Mar 26 2010We study the behaviour of the notion of "thema", introduced in our previous article [B.09b], by a change of variable. We show not only that the fundamental invariants of such a thema, corresponding to the Bernstein polynomial, are stable by a change of ... More

Tau lepton reconstruction at collider experiments using impact parametersJul 07 2015Nov 06 2015We present a novel method for the reconstruction of events containing pairs of hadronically decaying tau leptons at collider experiments. This method relies on accurate knowledge of the tau production vertex and precise measurement of its charged decay ... More

A polynomial invariant of diffeomorphisms of 4-manifoldsNov 23 1999We use a 1-parameter version of gauge theory to investigate the topology of the diffeomorphism group of 4-manifolds. A polynomial invariant, analogous to the Donaldson polynomial, is defined, and is used to show that the diffeomorphism group of certain ... More

Quantum Error Correction and Fault-ToleranceJul 18 2005I give an overview of the basic concepts behind quantum error correction and quantum fault tolerance. This includes the quantum error correction conditions, stabilizer codes, CSS codes, transversal gates, fault-tolerant error correction, and the threshold ... More

The Heisenberg Representation of Quantum ComputersJul 01 1998Since Shor's discovery of an algorithm to factor numbers on a quantum computer in polynomial time, quantum computation has become a subject of immense interest. Unfortunately, one of the key features of quantum computers - the difficulty of describing ... More

A Theory of Fault-Tolerant Quantum ComputationFeb 12 1997Feb 18 1997In order to use quantum error-correcting codes to actually improve the performance of a quantum computer, it is necessary to be able to perform operations fault-tolerantly on encoded states. I present a general theory of fault-tolerant operations based ... More

Pasting Quantum CodesJul 31 1996I describe a method for pasting together certain quantum error-correcting codes that correct one error to make a single larger one-error quantum code. I show how to construct codes encoding 7 qubits in 13 qubits using the method, as well as 15 qubits ... More

An obstruction to smooth isotopy in dimension 4Jul 09 1998Dec 14 1998Techniques of gauge theory are used to define and compute an invariant of certain diffeomorphisms of 4-manifolds. The invariant vanishes for any diffeomorphism which is smoothly isotopic to the identity. As an application, we give the first example of ... More

Transverse polarization distribution and fragmentation functionsDec 11 1999Apr 27 2000We discuss transverse polarization distribution and fragmentation functions, in particular, T-odd functions with transverse momentum dependence, which might be relevant for the description of single transverse spin asymmetries. The role of intrinsic tranverse ... More

Transverse Lambda Polarization at LHCJul 09 2009Transverse polarization of Lambda hyperons produced in p p and p Pb collisions is discussed. A factorized description in the intermediate to high p_T region is considered that involves transverse momentum and spin dependence in the fragmentation process. ... More

Gluon saturation effects on single spin asymmetriesNov 29 2006We consider forward pion production in p p collisions at RHIC energies,which probes the so-called Extended Geometric Scaling region. Upon inclusion of small-x effects via an anomalous dimension within the Color Glass Condensate formalism at leading order ... More

Hadron structure from gamma^* p scattering: interpreting hadronic matrix elementsSep 30 2004Oct 05 2004Hadron structure from high-Q^2 gamma^* p scattering processes is often expressed in terms of hadronic matrix elements of nonlocal operators. Properly defining and interpreting these quantities is very important in light of experiments aiming to extract ... More

Transversely polarized Lambda productionJul 05 2000Transversely polarized Lambda production in hard scattering processes is discussed in terms of a leading twist T-odd fragmentation function which describes the fragmentation of an unpolarized quark into a transversely polarized Lambda. We focus on the ... More

The K3 category of a cubic fourfoldMay 07 2015Sep 12 2016Smooth cubic fourfolds are linked to K3 surfaces via their Hodge structures, due to work of Hassett, and via Kuznetsov's K3 category A. The relation between these two viewpoints has recently been elucidated by Addington and Thomas. In this paper, both ... More

Introduction to stability conditionsNov 07 2011Oct 25 2012These are notes of a course given at the 'school on moduli spaces' at the Newton Institute in January 2011. The abstract theory of stability conditions (due to Bridgeland and Douglas) on abelian and triangulated categories is developed via tilting and ... More

Derived and abelian equivalence of K3 surfacesApr 06 2006Tom Bridgeland constructed explicit stability conditions on K3 surfaces. This paper attempts to shed more light on these particular examples, especially on the hearts of the underlying t-structures. We prove that two K3 surfaces X and X' are derived equivalent ... More

The Kaehler cone of a compact hyperkaehler manifoldSep 19 1999Jun 03 2001This is an attempt towards the understanding of the (birational) Kaehler cone of a compact hyperkaehler manifold in terms of the Beauville-Bogomolov form on its second cohomology. We discuss birational correspondences between hyperkaehler manifolds and ... More

Birational symplectic manifolds and their deformationsJan 17 1996Jan 17 1996The known counterexamples to the global Torelli theorem for higher-dimensional hyperkahler manifolds are provided by birational manifolds. We address the question whether two birational hyperkahler manifolds (i.e. irreducible symplectic) manifolds always ... More

Dynamics of Accretion Flows Irradiated by a QuasarFeb 21 2007We present the results from axisymmetric time-dependent HD calculations of gas flows which are under the influence of gravity of a black hole in quasars. We assume that the flows are non-rotating and exposed to quasar radiation. We take into account X-ray ... More

Theory of winds in AGNsJan 04 2007I present a brief review of theory of winds in active galactic nuclei (AGN). Magnetic, radiation, and thermal driving likely operate in AGN. In many cases, it is difficult to distinguish, both from observational and theoretical point of view, which of ... More

Virial statistical description of non-extensive hierarchical systemsMay 26 2006In a first part the scope of classical thermodynamics and statistical mechanics is discussed in the broader context of formal dynamical systems, including computer programmes. In this context classical thermodynamics appears as a particular theory suited ... More

Novel type of orbital ordering: complex orbitals in doped Mott insulatorsApr 04 2000Apr 05 2000An orbital ordering, often observed in Mott insulators with orbital degeneracy, is usually supposed to disappear with doping, e.g. in the ferromagnetic metallic phase of manganites. We propose that the orbital ordering of a novel type may exist in such ... More

Aubry sets vs Mather sets in two degrees of freedomMar 18 2008Sep 04 2009We study autonomous Tonelli Lagrangians on closed surfaces. We aim to clarify the relationship between the Aubry set and the Mather set, when the latter consists of periodic orbits which are not fixed points. Our main result says that in that case the ... More

Nature's softwareApr 20 2014I bring forward some arguments to support the thesis that nature is fundamentally discrete, and present my own thoughts about the direction in which one could look for a possible, consistent "theory of everything" describing gravitation and quantum particles. ... More

Local Geometry of Singular Real Analytic SurfacesJan 15 1999Let V be a compact real analytic surface with isolated singularities embedded in $R^N$, and assume its smooth part is equipped with a Riemannian metric that is induced from some analytic Riemannian metric on $R^N$. We prove: 1. Each point of V has a neighborhood ... More

A Strong Edge-Coloring of Graphs with Maximum Degree 4 Using 22 ColorsJan 25 2006In 1985, Erd\H{o}s and Ne\'{s}etril conjectured that the strong edge-coloring number of a graph is bounded above by ${5/4}\Delta^2$ when $\Delta$ is even and ${1/4}(5\Delta^2-2\Delta+1)$ when $\Delta$ is odd. They gave a simple construction which requires ... More

Warm dark matter at small scales: peculiar velocities and phase space densityNov 09 2010May 03 2011We study the scale and redshift dependence of the power spectra for density perturbations and peculiar velocities, and the evolution of a coarse grained phase space density for (WDM) particles that decoupled during the radiation dominated stage. The (WDM) ... More

Limit groups for relatively hyperbolic groups, I: The basic toolsDec 24 2004Mar 20 2008We begin the investigation of Gamma-limit groups, where Gamma is a torsion-free group which is hyperbolic relative to a collection of free abelian subgroups. Using the results of Drutu and Sapir, we adapt the results from math.GR/0404440 to this context. ... More

Quantum Brownian representation for the quantum field modesNov 02 2007May 26 2009When analyzing the particle-like excitations in quantum field theory it is natural to regard the field mode corresponding to the particle momentum as an open quantum system, together with the opposite momentum mode. Provided that the state of the field ... More

On Lower Bound Methods for Tree-like Cutting Plane ProofsJan 05 2013In the book Boolean Function Complexity by Stasys Jukna, two lower bound techniques for Tree-like Cutting Plane proofs (henceforth, "Tree-CP proofs") using Karchmer-Widgerson type communication games (henceforth, "KW games") are presented: The first, ... More

Chiral 1/M^2 corrections to B^(*) -> D^(*) at Zero Recoil in Quenched Chiral Perturbation TheoryOct 14 2002Heavy quark effective theory can be used to calculate the values of the semileptonic B^(*) -> D^(*) decays in the limit that the heavy quark masses are infinite. We calculate the lowest order chiral corrections, which are of O(1/M^2), from the breaking ... More

How a quark-gluon plasma phase modifies the bounds on extra dimensions from SN 1987aFeb 16 2001Jul 23 2001The shape of the neutrino pulse from the supernova SN1987a provides one of the most stringent constraints on the size of large, compact, "gravity-only" extra dimensions. Previously, calculations have been carried out for a newly-born proto-neutron star ... More

Black Hole Entropy and Entropy of EntanglementMar 03 1995Jul 20 1995We compare the one-loop corrections to the entropy of a black hole, from quantum fields of spin zero, one-half, and one, to the entropy of entanglement of the fields. For fields of spin zero and one-half the black hole entropy is identical to the entropy ... More

Validity of the Eikonal ApproximationApr 30 1992We summarize results on the reliability of the eikonal approximation in obtaining the high energy behavior of a two particle forward scattering amplitude. Reliability depends on the spin of the exchanged field. For scalar fields the eikonal fails at eighth ... More

Conductivity of a quasiperiodic system in two and three dimensionsDec 19 2006Feb 07 2007A generalization of the Aubry-Andre model in two and three dimensions is introduced which allows for quasiperiodic hopping terms in addition to the quasiperiodic site potentials. This corresponds to an array of interstitial impurities within the periodic ... More

Theory of copolymer micellizationJun 25 2003We consider the micellization of block copolymers in solution, employing self consistent field theory with an additional constraint that permits the examination of intermediate structures. From the information for an isolated micelle (structure, binding ... More

The formal theory of Tannaka dualityDec 22 2011A Tannakian category is an abelian tensor category equipped with a fiber functor and additional structures which ensure that it is equivalent to the category of representations of some affine groupoid scheme acting on the spectrum of a field extension. ... More

Positive scalar curvature, diffeomorphisms and the Seiberg-Witten invariantsMay 03 2001Jan 15 2002We study the space of positive scalar curvature (psc) metrics on a 4-manifold, and give examples of simply connected manifolds for which it is disconnected. These examples imply that concordance of psc metrics does not imply isotopy of such metrics. This ... More

On a numerical approximation scheme for construction of the early exercise boundary for a class of nonlinear Black-Scholes equationsSep 29 2010Apr 06 2011The purpose of this paper is to construct the early exercise boundary for a class of nonlinear Black--Scholes equations with a nonlinear volatility depending on the option price. We review a method how to transform the problem into a solution of a time ... More

Radiative Thrusters on Close-in Extrasolar PlanetsMar 13 2008The atmospheres of close-in extrasolar planets absorb most of the incident stellar radiation, advect this energy, then reradiate photons in preferential directions. Those photons carry away momentum, applying a force on the planet. Here we evaluate the ... More

Compressibility effects on the Rayleigh-Taylor instability growth between immiscible fluidsOct 16 2003The linearized Navier-Stokes equations for a system of superposed immiscible compressible ideal fluids are analyzed. The results of the analysis reconcile the stabilizing and destabilizing effects of compressibility reported in the literature. It is shown ... More

The contact process in a dynamic random environmentJan 16 2009We study a contact process running in a random environment in $\mathbb {Z}^d$ where sites flip, independently of each other, between blocking and nonblocking states, and the contact process is restricted to live in the space given by nonblocked sites. ... More