Physics Department · Theoretical Division Università degli Studi di Milano · INFN Milano
Milano 1 String Theory Group

Seminars

Upcoming

30 Nov

Regular Strings Seminar

Bethe Ansatz equations, Calogero-Moser systems and elliptic functions

Mario De Marco, Université Libre de Bruxelles

Aula Teorici

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The superconformal indeces of 4d SCFTs count their BPS states and, holographically, give information on the microstates of the dual black holes. A possible approach to the exact computation of the index requires solving the so-called Bethe Ansatz equations (BAE). In this talk, I will introduce a rewriting of the BAE in terms of elliptic functions, focusing on the case with 16 supercharges. Such a rewriting permits 1) to quantitatively capture the conjectural relation of BAE with the Calogero-Moser integrable system (and the related continuous solutions) and 2) to rephrase the BAE in terms of configurations of lines on a plane intersecting an elliptic curve.

Past seminars

14 seminars in 2003

18 Dec

Lunch seminar

Spin chains and anomalous dimensions in N=4

Stefano Maghini, Physics Dept. - Theory Division - Universita' degli Studi di Milano

Room DC/1/26

9 Dec

Lunch seminar

On spinning strings and AdS/CFT

Luca Martucci, Physics Dept. - Theory Division - Universita' degli Studi di Milano

Room DC/1/26

27 Nov

Lunch seminar

On exact solutions in string theory

Sergio Cacciatori, Mathematics Dept. - Universita' degli Studi di Milano

Room DC/1/26

18 Nov

Lunch seminar

On giant gravitons

Pedro J. Silva, Physics Dept. - Theory Division - Universita' degli Studi di Milano

Room DC/1/26

13 Nov

Gauge theories on finite group spaces

Leonardo Castellani, Universita' del Piemonte Orientale

Sala Consiglio

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La geometria differenziale dei gruppi finiti viene utilizzata per definire teorie di campo sulle corrispondenti "varieta'" discrete.

11 Nov

Branes in the Poisson sigma model and deformation quantization of constrained systems

Alberto Cattaneo, Institut fuer Mathematik, Universitaet Zuerich

Room DC/1/26

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The Poisson sigma model is a topological string theory with target a Poisson manifold (i.e., a manifold whose algebra of smooth functions is endowed with a Lie bracket that is also a derivation; e.g., a symplectic manifold). Particularly interesting is the case of open strings in genus zero (i.e., the worldsheet is a disk) as its perturbative functional integral quantization with "free" boundary conditions yields Kontsevich's formula for the deformation quantization of the target (i.e., an associative algebra structure on formal power series in Plank's constant of smooth functions such that the commutator yields the Poisson bracket in the classical limit). In this talk we address the problem of changing the boundary conditions ("branes"). It turns out that the possible branes are coisotropic submanifolds (the global version of Dirac's first class constraints, which appear when one has to do with systems with symmetry - from Lagrange's top to, in infinite dimensions, Yang-Mills theory). The functional integral quantization of the Poisson sigma model with branes yields interesting formulae including (when obstruction are absent) the deformation quantization of the reduced phase space of a given coisotropic submanifold.

11 Nov

Lunch seminar

Comments on Ferrara, Sokatchev article "Non-anticommutative N=2 super-Yang-Mills theory with singlet deformation"

Sergio Cacciatori, Mathematics Dept. - Universita' degli Studi di Milano

Room DC/1/26

5 Nov

Supersymmetric solutions of N=2, D=4 gauged supergravity

Marco Caldarelli, Physics Dept. - Theory Division - Universita' degli Studi di Milano

Room DC/1/26

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We consider minimal gauged supergravity in four dimensions. After a short introduction to the main features of the theory, we construct all bosonic solutions admitting a Killing spinor. These solutions preserve generically one quarter of the supersymmetries, and fall in two classes, distinguished by the norm of the Killing vector constructed from the Killing spinor. If the Killing vector is timelike, the solutions are determined by the geometry of a two-dimensional base-manifold. When it is lightlike, the most general BPS solution is given by an electrovac AdS travelling wave. Finally, we generalize the classification to include external sources, and show that a particular solution describes a Goedel-type universe preserving one quarter of the supersymmetries.

30 Oct

Noncommutative Geometry in Physics

Luis Alvarez-Gaume', Theoretical Physics Division - CERN

Sala Consiglio

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Since the development of Noncommutative Geometry, there have been some attempts to apply it in Physics. These attempts have been so far limited success, but many more possibilities remain open. We will present some aspects of these applications, and some prospects for the future.

29 Oct

Compactifications of type IIA and 11-d supergravity with fluxes

Klaus Behrndt, Max Planck Institut fuer Gravitationsphysik, Albert Einstein Institut, Potsdam

Room DC/1/26

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We consider compactifications of 11-d supergravity in the presence of fluxes and derive the constraints imposed by supersymmetry. The deformations on the geometry of the internal space are discussed. The compactification of type IIA supergravity appears as a special case.

23 Oct

QCD meets strings

Anastasios Petkou, Theoretical Physics Division - CERN

Sala Consiglio

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String theory was invented in the 70s to explain some phenomena in Strong Interactions, but quickly turned into a possible Theory of Everything. However, the recent discovery of AdS/CFT and the idea of Holography enabled String Theory to address basic questions regarding its starting point: Strong Interactions.
After a review of the main ideas behind AdS/CFT and Holography, I discuss Semiclassical String configurations in Anti-de Sitter spacetimes and the new information they give for the anomalous dimensions, the glueball spectrum and the thermodynamics of Non-Abelian Gauge Theories.

1 Oct

Chern-Simons deformation of General Relativity

Roman Jackiw, Center for Theoretical Physics - Department of Physics, MIT

Sala Consiglio

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General relativity is extended by promoting the three-dimensional gravitational Chern-Simons term to four dimensions. This entails choosing an embedding coordinate v_\mu -- an external quantity, which we fix to be a non-vanishing constant in its time component. The theory is identical to one in which the embedding coordinate is itself a dynamical variable, rather than a fixed, external quantity. Consequently diffeomorphism symmetry breaking is hidden in the modified theory: the Schwarzschild metric is a solution; gravitational waves possess two polarizations, each traveling at the velocity of light; a conserved energy-momentum (pseudo-) tensor can be constructed. The modification is visible in the intensity of gravitational radiation: the two polarizations of a gravity wave carry intensities that are suppressed/enchanced by the extension.

4 Jun

Classifying supergravity solutions

Jerome Gauntlett, Queen Mary - Physics Department, London

Room DC/1/26

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Supergravity solutions have played, and continue to play, an important role in string/M-theory. Most supergravity solutions have been constructed by guessing a suitable Ansatz, and so it is desirable to have a more systematic procedure. We will discuss a method which enables one to classify supergravity all solutions utilising the mathematical notion of G-structures.

25 Feb

Physics colloquium

Forces, fundamental symmetries and basic constituents of the universe

Sergio Ferrara, Theoretical Physics Division - CERN

Main hall "aula A"

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An update is given on recent progress in the quest for a unified theory encompassing the fundamental interactions of particles and fields. New concepts, such as extended objects (branes) and duality, and older concepts such as renormalizability and supersymmetry, are merged in concepts such as renormalizability and supersymmetry, are merged in the search for a unitary scheme.