Subject: [Depfis] Strings@ar: XLV Encuentro , IAFE, miércoles 9-marzo

From: [email-masked]
Date: Mon, 28 Feb 2011 13:42:40 -0300

Estimados Colegas y Amigos,

Tenemos el agrado de anunciarles que el próximo miércoles, 9 de marzo,
tendrá lugar el próximo encuentro de la red Strings@ar en el IAFE, Ciudad
Universitaria, Buenos Aires.

El programa será el siguiente:

10:50 - 11:00 Apertura
11:00 - 12:00 Marc Henneaux (Université Libre de Bruxelles)
              Asymptotic structure of three-dimensional anti-de Sitter
                 gravity
12:00 - 13:30 Almuerzo
13:30 - 14:30 Osvaldo Santillán (Universidad de Buenos Aires)
              Simple examples of the DV (Dijkgraaf-Vafa) realization of the
                 AGT conjecture
14:30 - 15:00 Café
15:00 - 16:00 Rafael Ferraro (IAFE, CONICET-UBA)
              Searching for solutions to Born-Infeld equations
16:00 - 16:30 Café
16:30 - 17:30 Raúl Arias (Universidad Nacional de La Plata)
              Lorentzian AdS, Wormholes and Holography

Abajo se detallan los resúmenes de las charlas.

Un cordial saludo,

---
Jose Edelstein
Nicolas Grandi
Carmen Nuñez
Martin Schvellinger

Más información en:
http://www.fisica.unlp.edu.ar/strings/

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Abstracts:
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Marc Henneaux (Université Libre de Bruxelles)
Asymptotic structure of three-dimensional anti-de Sitter gravity

Abstract:

The asymptotic structure of three-dimensional gravity with a negative
cosmological constant is reviewed with a special emphasis on the central
charge that appears in the asymptotic conformal symmetry algebra. Various
extensions are discussed (including higher spins).

------------------------------------------------------------------------

Osvaldo Santillán (Universidad de Buenos Aires)
Simple examples of the DV (Dijkgraaf-Vafa) realization of the AGT conjecture

Abstract:

We discuss some generalities about Penner models and Chern-Simons
topological field theories, in connection with the Dijkgraaf-Vafa
realization of the AGT conjecture. The Nekrasov partition for N=2 super
Yang Mills with U(1) gauge group is analized and a matrix model which
realize this partition function by a double scaling limit is described.
The relation between this model and the expectation value of knot
operators in certain toric background considered by M. Marino is pointed
out explicitly.

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Rafael Ferraro (IAFE, CONICET-UBA)
Searching for solutions to Born-Infeld equations

Abstract:

The building of Born-Infeld electrostatic configurations in the plane
implies the integration of a non-holomorphic complex potential. This
potential is entirely determined by the choice of a holomorphic function
linking the potential to an auxiliary complex field closely related to the
electrostatic field. The procedure to obtain Born-Infeld electrostatic
configurations is exemplified by solving the multipoles. Besides, it is
shown that the attractive force between two equal but opposite charges is
lower than its Coulombian partner; it decreases up to vanish when the
charges approach each other below a distance ruled by the Born-Infeld
constant.

------------------------------------------------------------------------

Raúl Arias (Universidad Nacional de La Plata)
Lorentzian AdS, Wormholes and Holography

Abstract:

We investigate the structure of two point functions for the QFT dual to an
asymptotically Lorentzian AdS-wormhole. The bulk geometry is a solution of
5-dimensional second order Einstein Gauss Bonnet gravity and causally
connects two asymptotically AdS spacetimes. We revisit the GKPW
prescription for computing two-point correlation functions for dual QFT
operators $\cal O$ in Lorentzian signature and we propose to express the
bulk fields in terms of the independent boundary values $\phi_0^\pm$ at
each of the two asymptotic AdS regions, along the way we exhibit how the
ambiguity of normalizable modes in the bulk, related to initial and final
states, show up in the computations. The independent boundary values are
interpreted as sources for dual operators $\cal O^\pm$ and we argue that,
apart from the possibility of entanglement, there exists a coupling
between the degrees of freedom living at each boundary. The AdS$_{1+1}$
geometry is also discussed in view of its similar boundary structure.
Based on the analysis, we propose a very simple geometric criterium to
distinguish coupling from entanglement effects among two sets of degrees
of freedom associated to each of the disconnected parts of the boundary.