strings@ar

XLV Encuentro de la red strings@ar
Miércoles 9 de marzo de 2011, IAFE
PROGRAMA


Miércoles 9 de marzo de 2011
IAFE, Ciudad Universitaria, Buenos Aires
10h50 - 11h00 Apertura
11h00 - 12h00   Marc Henneaux (Université Libre de Bruxelles)  
  Asymptotic structure of three-dimensional anti-de Sitter gravity  
12h00 - 13h30 Almuerzo
13h30 - 14h30   Osvaldo Santillán (Universidad de Buenos Aires)  
  Simple examples of the DV (Dijkgraaf-Vafa) realization of the AGT conjecture  
14h30 - 15h00 Café
15h00 - 16h00   Rafael Ferraro (IAFE, CONICET-UBA)  
  Searching for solutions to Born-Infeld equations  
16h00 - 16h30 Café
16h30 - 17h30   Raúl Arias (Universidad Nacional de La Plata)  
  Lorentzian AdS, Wormholes and Holography  

Marc Henneaux (Université Libre de Bruxelles)
Asymptotic structure of three-dimensional anti-de Sitter gravity
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
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. Mariño is pointed out explicitly.

Rafael Ferraro (IAFE, CONICET-UBA)
Searching for solutions to Born-Infeld equations
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
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 O in Lorentzian signature and we propose to express the bulk fields in terms of the independent boundary values φ0± 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 O± and we argue that, apart from the possibility of entanglement, there exists a coupling between the degrees of freedom living at each boundary. The AdS1+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.