Results for "L. Bonora"

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Two-matrix model and c=1 string theoryMay 02 1994May 12 1994We show that the most general two--matrix model with bilinear coupling underlies $c=1$ string theory. More precisely we prove that $W_{1+\infty}$ constraints, a subset of the correlation functions and the integrable hierarchy characterizing such two--matrix ... More
Perturbative Anomalies of the M-5-braneOct 07 1997Oct 21 1997We discuss several mechanisms to cancel the anomalies of a 5-brane embedded in M-theory. Two of them work, provided we impose suitable conditions either on the 11-dimensional manifold of M-theory or on the 4-form field strength of M-theory.
Generalized q-deformed Correlation Functions as Spectral Functions of Hyperbolic GeometryMay 19 2014We analyse the role of vertex operator algebra and 2d amplitudes from the point of view of the representation theory of infinite dimensional Lie algebras, MacMahon and Ruelle functions. A p-dimensional MacMahon function is the generating function of p-dimensional ... More
Chiral anomalies in noncommutative gauge theoriesSep 26 2001Oct 02 2001Using cohomological methods we discuss several issues related to chiral anomalies in noncommutative U(N) YM theories in any even dimension. We show that for each dimension there is only one solution of the WZ consistency condition and that there cannot ... More
Hamiltonian structure and coset construction of the supersymmetric extensions of N=2 KdV hierarchyApr 29 1997Jul 08 1997A manifestly N=2 supersymmetric coset formalism is applied to analyse the "fermionic" extensions of N=2 $a=4$ and $a=-2$ KdV hierarchies. Both these hierarchies can be obtained from a manifest N=2 coset construction. This coset is defined as the quotient ... More
Weyl transformations and trace anomalies in N=1, D=4 supergravitiesMay 30 2013Jul 07 2013We identify the supersymmetric extension of Weyl transformations in various types of supergravities, the minimal, nonminimal and new minimal N=1 SUGRA in 4D, formulated in terms of superfields. Based also on previous results we conclude that there are ... More
Normal Bundles, Pfaffians and AnomaliesDec 22 1999Jan 04 2000We deal with the problem of diffeomorphism anomaly in theories with branes. In particular we thoroughly analyze the problem of the residual chiral anomaly of a five-brane immersed in M-theory, paying attention to its global formulation in the five-brane ... More
The Hamiltonian structure of the N=2 supersymmetric GNLS hierarchyApr 17 1997The first two Hamiltonian structures and the recursion operator connecting all evolution systems and Hamiltonian structures of the N=2 supersymmetric (n,m)-GNLS hierarchy are constructed in terms of N=2 superfields in two different superfield bases with ... More
Liouville and Toda field theories on Riemann surfacesMar 10 1993We study the Liouville theory on a Riemann surface of genus g by means of their associated Drinfeld--Sokolov linear systems. We discuss the cohomological properties of the monodromies of these systems. We identify the space of solutions of the equations ... More
The N=2 supersymmetric Toda lattice and matrix modelsOct 15 1997We propose a new integrable N=2 supersymmetric Toda lattice hierarchy which may be relevant for constructing a supersymmetric one-matrix model. We define its first two Hamiltonian structures, the recursion operator and Lax--pair representation. We provide ... More
BRST, anti-BRST and their geometryNov 25 2009Jul 23 2010We continue the comparison between the field theoretical and geometrical approaches to the gauge field theories of various types, by deriving their Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST trasformation properties and comparing them with the geometrical ... More
Partition Functions for Quantum Gravity, Black Holes, Elliptic Genera and Lie Algebra HomologiesMay 23 2011There is a remarkable connection between quantum generating functions of field theory and formal power series associated with dimensions of chains and homologies of suitable Lie algebras. We discuss the homological aspects of this connection with its ... More
Fluxes, Brane Charges and Chern Morphisms of Hyperbolic GeometryFeb 16 2006Mar 31 2006The purpose of this paper is to provide the reader with a collection of results which can be found in the mathematical literature and to apply them to hyperbolic spaces that may have a role in physical theories. Specifically we apply K-theory methods ... More
Topological Field Theory Interpretations and LG Representation of c=1 String TheoryMay 23 1995May 29 1995We analyze the topological nature of $c=1$ string theory at the self--dual radius. We find that it admits two distinct topological field theory structures characterized by two different puncture operators. We show it first in the unperturbed theory in ... More
The (N,M)-th KdV hierarchy and the associated W algebraNov 11 1993We discuss a differential integrable hierarchy, which we call the (N, M)$--th KdV hierarchy, whose Lax operator is obtained by properly adding $M$ pseudo--differential terms to the Lax operator of the N--th KdV hierarchy. This new hierarchy contains both ... More
Multi-matrix models without continuum limitDec 10 1992Jun 22 1993We derive the discrete linear systems associated to multi--matrix models, the corresponding discrete hierarchies and the appropriate coupling conditions. We also obtain the $W_{1+\infty}$ constraints on the partition function. We then apply to multi--matrix ... More
Matrix models without scaling limitSep 13 1992Nov 24 1992In the context of hermitean one--matrix models we show that the emergence of the NLS hierarchy and of its reduction, the KdV hierarchy, is an exact result of the lattice characterizing the matrix model. Said otherwise, we are not obliged to take a continuum ... More
Integrable Structures in String Field TheoryNov 28 2002Dec 03 2002We give a simple proof that the Neumann coefficients of surface states in Witten's SFT satisfy the Hirota equations for dispersionless KP hierarchy. In a similar way we show that the Neumann coefficients for the three string vertex in the same theory ... More
Extended Toda lattice hierarchy, extended two-matrix model and c=1 string theoryJul 21 1994We show how the two--matrix model and Toda lattice hierarchy presented in a previous paper can be solved exactly: we obtain compact formulas for correlators of pure tachyonic states at every genus. We then extend the model to incorporate a set of discrete ... More
Multi-field representations of KP hierarchies and multi-matrix modelsMay 03 1993May 04 1993We discuss the integrable hierarchies that appear in multi--matrix models. They can be envisaged as multi--field representations of the KP hierarchy. We then study the possible reductions of this systems via the Dirac reduction method by suppressing successively ... More
An alternative approach to KP hierarchy in matrix modelsApr 08 1992We show that there exists an alternative procedure in order to extract differential hierarchies, such as the KdV hierarchy, from one--matrix models, without taking a continuum limit. To prove this we introduce the Toda lattice and reformulate it in operator ... More
BRST, anti-BRST and gerbesJul 26 2007Feb 23 2009We discuss BRST and anti--BRST transformations for an Abelian antisymmetric gauge field in 4D and find that, in order for them to anticommute, we have to impose a condition on the auxiliary fields. This condition is similar to the Curci-Ferrari condition ... More
New Spinor Fields on Lorentzian 7-ManifoldsAug 06 2015Jan 10 2016This paper deals with the classification of spinor fields according to the bilinear covariants in 7 dimensions. The previously investigated Riemannian case is characterized by either one spinor field class, in the real case of Majorana spinors, or three ... More
On the string interpretation of M(atrix) theoryMay 19 1997May 28 1997It has been proposed recently that, in the framework of M(atrix) theory, N=8 supersymmetric U(N) Yang-Mills theory in 1+1 dimensions gives rise to type IIA long string configurations. We point out that the quantum moduli space of $SYM_{1+1}$ gives rise ... More
Correlation functions of two-matrix modelsNov 16 1993Jan 19 1994We show how to calculate correlation functions of two matrix models. Our method consists in making full use of the integrable hierarchies and their reductions, which were shown in previous papers to naturally appear in multi--matrix models. The second ... More
The energy of the analytic lump solution in SFTMay 30 2011Aug 01 2013In a previous paper a method was proposed to find exact analytic solutions of open string field theory describing lower dimensional lumps, by incorporating in string field theory an exact renormalization group flow generated by a relevant operator in ... More
Flavour from partially resolved singularitiesMar 10 2006In this letter we study topological open string field theory on D--branes in a IIB background given by non compact CY geometries ${\cal O}(n)\oplus{\cal O}(-2-n)$ on $\P1$ with a singular point at which an extra fiber sits. We wrap $N$ D5-branes on $\P1$ ... More
Conifold geometries, matrix models and quantum solutionsNov 15 2005This paper is a continuation of hepth/0507224 where open topological B-models describing D-branes on 2-cycles of local Calabi--Yau geometries with conical singularities were studied. After a short review, the paper expands in particular on two aspects: ... More
Matrix String Theory, 2D SYM Instantons and affine Toda systemsMay 12 1998May 25 1998Extending a recent result of S.B. Giddings, F. Hacquebord and H. Verlinde, we show that in the U(N) SYM Matrix theory there exist classical BPS instantons which interpolate between different closed string configurations via joining/splitting interactions ... More
Toward the construction of N=2 supersymmetric integrable hierarchiesApr 25 1996May 07 1996We formulate a conjecture for the three different Lax operators that describe the bosonic sectors of the three possible $N=2$ supersymmetric integrable hierarchies with $N=2$ super $W_n$ second hamiltonian structure. We check this conjecture in the simplest ... More
String Interactions from Matrix String TheoryJul 30 1998Sep 18 1998The Matrix String Theory, i.e. the two dimensional U(N) SYM with N=(8,8) supersymmetry, has classical BPS solutions that interpolate between an initial and a final string configuration via a bordered Riemann surface. The Matrix String Theory amplitudes ... More
Ghost story. III. Back to ghost number zeroAug 01 2009Nov 05 2009After having defined a 3-strings midpoint-inserted vertex for the bc system, we analyze the relation between gh=0 states (wedge states) and gh=3 midpoint duals. We find explicit and regular relations connecting the two objects. In the case of wedge states ... More
Enhanced gauge symmetries on elliptic K3Jul 08 1998We show that the geometry of K3 surfaces with singularities of type A-D-E contains enough information to reconstruct a copy of the Lie algebra associated to the given Dynkin diagram. We apply this construction to explain the enhancement of symmetry in ... More
Analytic solutions for Dp branes in SFTJun 20 2011This is the follow-up of a previous paper [ArXiv:1105.5926], where we calculated the energy of an analytic lump solution in SFT, representing a D24-brane. Here we describe an analytic solution for a Dp-brane, for any p, and compute its energy.
Lump solutions in SFT. ComplementsSep 20 2011May 18 2012Recently a possible violation of the equation of motion for the recently proposed lump solutions in open SFT has been pointed out in the literature. In this paper we argue that, when the issue is considered in the appropriate mathematical setting of distribution ... More
Coset approach to the N=2 supersymmetric matrix GNLS hierarchiesNov 20 1997Nov 21 1997We discuss a large class of coset constructions of the N=2 sl(n|n-1) affine superalgebra. We select admissible subalgebras, i.e. subalgebras that induce linear chiral/antichiral constraints on the coset supercurrents. We show that all the corresponding ... More
The N=2 supersymmetric matrix GNLS hierarchiesNov 13 1997Nov 20 1997We construct the matrix generalization of the N=2 supersymmetric GNLS hierarchies. This is done by exhibiting the corresponding matrix super Lax operators in terms of N=2 superfields in two different superfield bases. We present the second Hamiltonian ... More
Multi-Matrix Models: Integrability Properties and Topological ContentJun 19 1995We analyze multi--matrix chain models. They can be considered as multi--component Toda lattice hierarchies subject to suitable coupling conditions. The extension of such models to include extra discrete states requires a weak form of integrability. The ... More
Conifold geometries, topological strings and multi-matrix modelsJul 22 2005Sep 12 2005We study open B-model representing D-branes on 2-cycles of local Calabi--Yau geometries. To this end we work out a reduction technique linking D-branes partition functions and multi-matrix models in the case of conifold geometries so that the matrix potential ... More
Elliptic Genera and Characteristic $q$-Series of Superconformal Field TheoryApr 08 2015We analyze the characteristic series, the $KO$ series and the series associated with the Witten genus, and their analytic forms as the $q$-analogs of classical special functions (in particular $q$-analog of the beta integral and the gamma function). $q$-series ... More
A note on consistent anomalies in noncommutative YM theoriesFeb 24 2000Mar 03 2000Via descent equations we derive formulas for consistent gauge anomalies in noncommutative Yang-Mills theories.
Anomalies and Locality in Field Theories and M theoryDec 22 1997We review some basic notions on anomalies in field theories and superstring theories, with particular emphasis on the concept of locality. The aim is to prepare the ground for a discussion on anomalies in theories with branes. In this light we review ... More
Integrable Discrete Linear Systems and One-Matrix ModelSep 27 1991In this paper we analyze one-matrix models by means of the associated discrete linear systems. We see that the consistency conditions of the discrete linear system lead to the Virasoro constraints. The linear system is endowed with gauge invariances. ... More
String Partition Functions, Hilbert Schemes, and Affine Lie Algebra Representations on Homology GroupsJun 04 2012This review paper contains a concise introduction to highest weight representations of infinite dimensional Lie algebras, vertex operator algebras and Hilbert schemes of points, together with their physical applications to elliptic genera of superconformal ... More
The integrable hierarchy constructed from a pair of KdV-type hierarchies and its associated $W$ algebraAug 05 1994Sep 13 1994For any two arbitrary positive integers `$n$' and `$m$', using the $m$--th KdV hierarchy and the $(n+m)$--th KdV hierarchy as building blocks, we are able to construct another integrable hierarchy (referred to as the $(n,m)$--th KdV hierarchy). The $W$--algebra ... More
Exact Correlators of Two-Matrix ModelsDec 01 1994Aug 08 1995We compute exact solutions of two--matrix models, i.e. detailed genus by genus expressions for the correlation functions of these theories, calculated without any approximation. We distinguish between two types of models, the unconstrained and the constrained ... More
Matrix String Theory and its Moduli SpaceJan 20 1999Jan 28 1999The correspondence between Matrix String Theory in the strong coupling limit and IIA superstring theory can be shown by means of the instanton solutions of the former. We construct the general instanton solutions of Matrix String Theory which interpolate ... More
Heterotic Matrix String Theory and Riemann SurfacesMay 13 1999Jun 22 1999We extend the results found for Matrix String Theory to Heterotic Matrix String Theory, i.e. to a 2d O(N) SYM theory with chiral (anomaly free) matter and N=(8,0) supersymmetry. We write down the instanton equations for this theory and solve them explicitly. ... More
Spectral properties of ghost Neumann matricesJan 14 2008We continue the analysis of the ghost wedge states in the oscillator formalism by studying the spectral properties of the ghost matrices of Neumann coefficients. We show that the traditional spectral representation is not valid for these matrices and ... More
Free field representation of Toda field theoriesNov 24 1992We study the following problem: can a classical $sl_n$ Toda field theory be represented by means of free bosonic oscillators through a Drinfeld--Sokolov construction? We answer affirmatively in the case of a cylindrical space--time and for real hyperbolic ... More
Spinor Fields Classification in Arbitrary Dimensions and New Classes of Spinor Fields on 7-ManifoldsNov 06 2014A classification of spinor fields according to the associated bilinear covariants is constructed in arbitrary dimensions and metric signatures, generalizing Lounesto's 4D spinor field classification. In such a generalized classification a basic role is ... More
Noncommutative SO(n) and Sp(n) Gauge TheoriesJun 13 2000Jun 28 2000We study the generalization of noncommutative gauge theories to the case of orthogonal and symplectic groups. We find out that this is possible, since we are allowed to define orthogonal and symplectic subgroups of noncommutative unitary gauge transformations ... More
Instantons and scattering in N=4 SYM in 4DDec 22 1999Jan 05 2000We study classical solutions (ic-instantons) in N=4 SYM in 4D which, in the strong coupling limit, correspond to complex two-dimensional manifolds. Asymptotically in time the latter have boundaries represented by compact real three-manifolds. Therefore ... More
One-loop effective actions and higher spinsSep 07 2016Nov 14 2016The idea we advocate in this paper is that the one-loop effective action of a free (massive) field theory coupled to external sources (via conserved currents) contains complete information about the classical dynamics of such sources. We show many explicit ... More
Light-cone Superstring Field Theory, pp-wave background and integrability propertiesNov 01 2005Nov 09 2005We show that the three strings vertex coefficients in light--cone open string field theory satisfy the Hirota equations for the dispersionless Toda lattice hierarchy. We show that Hirota equations allow us to calculate the correlators of an associated ... More
Ghost story. II. The midpoint ghost vertexAug 01 2009Nov 05 2009We construct the ghost number 9 three strings vertex for OSFT in the natural normal ordering. We find two versions, one with a ghost insertion at z=i and a twist-conjugate one with insertion at z=-i. For this reason we call them midpoint vertices. We ... More
Bubbling AdS and Vacuum String Field TheoryFeb 01 2006Jun 09 2006We show that a family of 1/2--BPS states of $\N=4$ SYM is in correspondence with a family of classical solutions of VSFT with a $B$--field playing the role of the inverse Planck constant. We show this correspondence by relating the Wigner distributions ... More
Construction of exact Riemannian instanton solutionsAug 24 2002We give the exact construction of Riemannian (or stringy) instantons, which are classical solutions of 2d Yang-Mills theories that interpolate between initial and final string configurations. They satisfy the Hitchin equations with special boundary conditions. ... More
One-loop effective actions and higher spinsSep 07 2016Sep 15 2016The idea we advocate in this paper is that the one-loop effective action of a free (massive) field theory coupled to external sources (via conserved currents) contains complete information about the classical dynamics of such sources. We show many explicit ... More
Exact time-localized solutions in Vacuum String Field TheorySep 06 2004Feb 28 2005We address the problem of finding star algebra projectors that exhibit localized time profiles. We use the double Wick rotation method, starting from an Euclidean (unconventional) lump solution, which is characterized by the Neumann matrix being the conventional ... More
Worldline quantization of field theory, effective actions and $L_\infty$ structureFeb 08 2018We formulate the worldline quantization of a massive fermion model coupled to external higher spin sources. We use the relations obtained in this way to show that its regularized effective action is endowed with an $L_\infty$ symmetry. The same result ... More
Ghost story. I. Wedge states in the oscillator formalismJun 07 2007Sep 06 2007This paper is primarily devoted to the ghost wedge states in string field theory formulated with the oscillator formalism. Our aim is to prove, using such formalism, that the wedge states can be expressed as |n> = exp[{2-n}/2 ({\cal L}_0+{\cal L}_0^\daggert)]|0>, ... More
Fundamental strings in SFTJan 14 2005In this letter we show that vacuum string field theory contains exact solutions that can be interpreted as macroscopic fundamental strings. They are formed by a condensate of infinitely many completely space-localized solutions (D0-branes).
Generalized states in SFTApr 08 2013Oct 18 2013The search for analytic solutions in open string fields theory \`a la Witten often meets with singular expressions, which need an adequate mathematical formalism to be interpreted. In this paper we discuss this problem and propose a way to resolve the ... More
Proceedings to the 'Euroconference on Symmetries Beyond the Standard Model', 12. - 17. July 2003, Portoroz, Slovenia (Part 1 of 2)Jan 08 2004Contents of Part 1: 1. Status of the Standard Model(P.H. Frampton), 2. Cosmological Constraints from MBA and Polarization (A. Melchiorri), 3. AdS/CFT Correspondence and Unification at About 4 TeV (P.H. Frampton), 4. New Solutions in String Field Theory ... More
Pure contact term correlators in CFTNov 20 2015Feb 09 2016We discuss the case of correlators in CFT made of pure contact terms, without a corresponding bare part. We show two examples. The first is provided by the conformal limits of a free massive fermion theory in 3d. We show that the (conserved) current correlators ... More
Evaluating Astronomy Literacy of the General PublicAug 09 2013A scientifically literate society is important for many different reasons, some of which include democratic and scientific topics. This study was performed in order to identify topics in astronomy and science in general that may not be well understood ... More
Trace anomalies in chiral theories revisitedMar 11 2014Aug 29 2014Motivated by the search for possible CP violating terms in the trace of the energy-momentum tensor in theories coupled to gravity we revisit the problem of trace anomalies in chiral theories. We recalculate the latter and ascertain that in the trace of ... More
Regularization of energy-momentum tensor correlators and parity-odd termsMar 11 2015Mar 18 2015We discuss the problem of regularizing correlators in conformal field theories. The only way to do it in coordinate space is to interpret them as distributions. Unfortunately except for the simplest cases we do not have tabulated mathematical results. ... More
Chern-Simons Invariants on Hyperbolic Manifolds and Topological Quantum Field TheoriesJun 08 2016Oct 14 2016We derive formulas for the classical Chern-Simons invariant of irreducible $SU(n)$-flat connections on negatively curved locally symmetric three-manifolds. We determine the condition for which the theory remains consistent (with basic physical principles). ... More
Phase control of a longitudinal momentum entangled photon state by a deformable membrane mirrorNov 19 2009We propose a paradigmatic demonstration of the potentialities of a deformable mirror for closed-loop control of a two-photon momentum-entangled state, subject to phase fluctuations. A custom-made membrane mirror is used to set a relative phase shift between ... More
Bi-photon propagation control with optimized wavefront by means of Adaptive OpticsOct 08 2012We present an efficient method to control the spatial modes of entangled photons produced through SPDC process. Bi-photon beam propagation is controlled by a deformable mirror, that shapes a 404nm CW diode laser pump interacting with a nonlinear BBO type-I ... More
Aberration cancellation in quantum interferometryJul 18 2008Dec 03 2008We report the first experimental demonstration of even-order aberration cancellation in quantum interferometry. The effect is a spatial counterpart of the spectral group velocity dispersion cancellation, which is associated with spectral entanglement. ... More
Quantum interference between charge excitation paths in a solid state Mott insulatorOct 20 2009Aug 04 2015The competition between electron localization and de-localization in Mott insulators underpins the physics of strongly-correlated electron systems. Photo-excitation, which re-distributes charge between sites, can control this many-body process on the ... More
The Effect of Weak Gravitational Lensing on the Angular Distribution of Gamma-Ray BurstsJun 10 1996If Gamma-Ray Bursts (GRBs) are cosmologically distributed standard candles and are associated with the luminous galaxies, then the observed angular distribution of all GRBs is altered due to weak gravitational lensing of bursts by density inhomogeneities. ... More
Theory of charge fluctuations and domain relocation times in semiconductor superlatticesDec 07 2004Shot noise affects differently the nonlinear electron transport in semiconductor superlattices depending on the strength of the coupling among the superlattice quantum wells. Strongly coupled superlattices can be described by a miniband Boltzmann-Langevin ... More
New AdS(3) x G/H compactifications of chiral IIB supergravityMar 13 2000May 30 2000We present a new class of solutions of D=10, N=2 chiral supergravity. A nonvanishing background for the field strength G_{MNR} of the complex two-form triggers AdS_3 x M_7 compactifications, where M_7 is a 7-dimensional compact manifold. When M_7 is a ... More
Detailed analysis of quantum phase transitions within the $u(2)$ algebraOct 13 2009We analyze in detail the quantum phase transitions that arise in models based on the $u(2)$ algebraic description for bosonic systems with two types of scalar bosons. First we discuss the quantum phase transition that occurs in hamiltonians that admix ... More
Recent Results on $\psip$ Decays at BesMay 16 2005Recent results on $\psip$ decays, including 10 Vector + Pseudoscalar (VP) modes and $p\bar{p}\pi^0(\eta)$, are reported with $14\times10^6$ $\psip$ events collected with the BESII detector. Cross sections and form factors for $e^+e^- \to \wpi$, $\rho\eta$, ... More
Statistical consistency of quantum-classical hybridsJan 20 2012After formulating a no-go theorem for perfect quantum-classical hybrid systems, a new consistency requirement based on standard statistical considerations is noted. It is shown that such requirement is not fulfilled by the mean-field approach, nor by ... More
Derivative expansion of the heat kernel in curved spaceJun 13 2007Jul 02 2007The heat kernel in curved space-time is computed to fourth order in a strict expansion in the number of covariant derivatives. The computation is made for arbitrary non abelian gauge and scalar fields and for the Riemann connection in the coordinate sector. ... More
Phase space localization of antisymmetric functionsNov 05 2002Upper and lower bounds are written down for the minimum information entropy in phase space of an antisymmetric wave function in any number of dimensions. Similar bounds are given when the wave function is restricted to belong to any of the proper subspaces ... More
On the uniqueness of the expected stress-energy tensor in renormalizable field theoriesMar 15 1999Sep 17 1999It is argued that the ambiguity introduced by the renormalization in the effective action of a four-dimensional renormalizable quantum field theory is at most a local polynomial action of canonical dimension four. The allowed ambiguity in the expected ... More
Direct construction of the effective action of chiral gauge fermions in the anomalous sectorApr 14 2008Jul 25 2008The anomaly implies an obstruction to a fully chiral covariant calculation of the effective action in the abnormal parity sector of chiral theories. The standard approach then is to reconstruct the anomalous effective action from its covariant current. ... More
The induced Chern-Simons term at finite temperatureJan 09 2002It is argued that the derivative expansion is a suitable method to deal with finite temperature field theory, if it is restricted to spatial derivatives only. Using this method, a simple and direct calculation is presented for the radiatively induced ... More
Expansion of a Bose-Einstein Condensate in an atomic waveguideNov 15 2001The expansion of a Bose-Einstein condensate in an atomic waveguide is analyzed. We study different regimes of expansion, and identify a transient regime between one-dimensional and three-dimensional dynamics, in which the properties of the condensate ... More
Statistical Mechanics of Developable RibbonsFeb 24 2010Jun 11 2010We investigate the statistical mechanics of long developable ribbons of finite width and very small thickness. The constraint of isometric deformations in these ribbon-like structures that follows from the geometric separation of scales introduces a coupling ... More
A bracket polynomial for graphsAug 25 2008Jan 14 2009A knot diagram has an associated looped interlacement graph, obtained from the intersection graph of the Gauss diagram by attaching loops to the vertices that correspond to negative crossings. This construction suggests an extension of the Kauffman bracket ... More
Chapman-Enskog method and synchronization of globally coupled oscillatorsJun 12 2000Jul 10 2000The Chapman-Enskog method of kinetic theory is applied to two problems of synchronization of globally coupled phase oscillators. First, a modified Kuramoto model is obtained in the limit of small inertia from a more general model which includes ``inertial'' ... More
A Dynamical Cross-over Regime in the Transmission and Reflection Spectra of Evanescent Waves with 2D Arrays of Josephson JunctionsFeb 18 2013A dynamical cross-over regime is revealed when exposing a classical two-dimensional ordered Josephson junction (JJ) array to evanescent waves and tuning the incident microwave power. At the lowest possible temperature for these experiments, 1.1 K, and ... More
On compositions of d.c. functions and mappingsJun 05 2007A d.c. (delta-convex) function on a normed linear space is a function representable as a difference of two continuous convex functions. We show that an infinite dimensional analogue of Hartman's theorem on stability of d.c. functions under compositions ... More
Bounds on the Quenched Pressure and Main Eigenvalue of the Ruelle Operator for Brownian Type PotentialsMar 02 2016Jun 23 2016In this paper we consider a random potential derived from the Brownian motion. We obtain upper and lower bounds for the expected value of the main eigenvalue of the associated Ruelle operator and for its quenched topological pressure. We also exhibit ... More
Constraints on star formation theories from the Serpens molecular cloud and protoclusterJul 10 2002We have mapped the large-scale structure of the Serpens cloud core using moderately optically thick (13CO(1--0) and CS(2--1)) and optically thin tracers (C18O(1--0), C34S(2--1), and N2H+(1--0)), using the 16-element focal plane array operating at a wavelength ... More
Skew braces and the Yang-Baxter equationNov 10 2015Mar 16 2016Braces were introduced by Rump to study non-degenerate involutive set-theoretic solutions of the Yang-Baxter equation. We generalize Rump's braces to the non-commutative setting and use this new structure to study not necessarily involutive non-degenerate ... More
Optical Calibration For Jefferson Lab HKS SpectrometerNov 04 2005In order to accept very forward angle scattering particles, Jefferson Lab HKS experiment uses an on-target zero degree dipole magnet. The usual spectrometer optics calibration procedure has to be modified due to this on-target field. This paper describes ... More
Classification of Poisson-Lie T-dual models with two-dimensional targetsOct 16 2001Dec 20 2001Four-dimensional Manin triples and Drinfeld doubles are classified and corresponding two-dimensional Poisson-Lie T-dual sigma models on them are constructed. The simplest example of a Drinfeld double allowing decomposition into two nontrivially different ... More
The invariant factor of the chiral determinantJul 10 2008The coupling of spin 0 and spin 1 external fields to Dirac fermions defines a theory which displays gauge chiral symmetry. Quantum mechanically, functional integration of the fermions yields the determinant of the Dirac operator, known as the chiral determinant. ... More
Derivative expansion for the effective action of chiral gauge fermions. The abnormal parity componentDec 19 2000Mar 01 2001Explicit exact formulas are presented, for the leading order term in a strict chiral covariant derivative expansion, for the abnormal parity component of the effective action of two- and four-dimensional Dirac fermions in presence of scalar, pseudo-scalar, ... More
Representation of Complex ProbabilitiesJul 19 1996Let a ``complex probability'' be a normalizable complex distribution $P(x)$ defined on $\R^D$. A real and positive probability distribution $p(z)$, defined on the complex plane $\C^D$, is said to be a positive representation of $P(x)$ if $\langle Q(x)\rangle_P ... More
Gibbs sampling of complex valued distributionsOct 30 2015Sep 26 2016A new technique is explored for the Monte Carlo sampling of complex-valued distributions. The method is based on a heat bath approach where the conditional probability is replaced by a positive representation of it on the complex plane. Efficient ways ... More