## strings@ar

XXXVII Encuentro de la red strings@ar.

Martes 30 de junio de 2009, IAFE

PROGRAMA

XXXVII Encuentro de la red strings@ar - Programa (póster para imprimir)

Martes 30 de junio de 2009

IAFE, Ciudad Universitaria, Buenos Aires09h50 - 10h00 Apertura 10h00 - 11h00 Diego Marqués (Univ. Nacional de La Plata)

Generalized messengers for gauge mediation11h00 - 11h30 Café 11h30 - 12h30 Jorge Russo (ICREA, Univ. Barcelona)

Schwinger pair creation in gravity and in closed superstring theory12h30 - 14h00 Almuerzo 14h00 - 15h00 Marcelo Botta Cantcheff ((Univ. Nacional de La Plata)

String entanglement and D-branes as pure states15h00 - 15h30 Café 15h30 - 16h30 Mauricio Sturla (Univ. Nacional de La Plata)

Wormhole solutions to Hořava gravity

Diego Marqués (Univ. Nacional de La Plata)

Generalized messengers for gauge mediation

I will start giving a brief introduction to Gauge Mediation of low scale SUSY breaking and comment on recent developements, making particular focus on General Gauge Mediation (GGM). I will then show how GGM can be implemented through hidden sectors involving weakly coupled messengers, and describe the spectrum of soft masses they give rise to. The talk is based on my work: "Generalized messenger sector for gauge mediation of supersymmetry breaking and the soft spectrum" JHEP 0903 (2009) 038, arXiv:0901.1326 [hep-ph]

Jorge Russo (ICREA, Univ. Barcelona)

Schwinger pair creation in gravity and in closed superstring theory

We discuss the Schwinger pair creation process in the context of gravitational models with the back reaction of the electric field included in the geometry. The background is also an exact solution of type II superstring theory, where the electric field arises by Kaluza-Klein reduction. We obtain a closed formula for the pair creation rate that incorporates the gravitational back reaction. At weak fields it has the same structure as the general Schwinger formula, albeit pairs are produced by a combination of Schwinger and Unruh effect, the latter due to the presence of a Rindler horizon. In four spacetime dimensions, the rate becomes constant at strong electric fields. For states with mass of Kaluza-Klein origin, the rate has a power-like dependence in the electric field, rather than the familiar (non-perturbative) exponential dependence. We also reproduce the same formula from the string partition function for winding string states. Finally, we comment on the generalization to excited string states.

Marcelo Botta Cantcheff ((Univ. Nacional de La Plata)

String entanglement and D-branes as pure states

We study the entanglement of closed strings degrees of freedom in order to investigate the microscopic structure and statistics of objects as D-branes. By considering the macroscopic pure state (MPS-) limit, whenever the entanglement entropy goes to zero (in such a way that the macroscopic properties of the state are preserved), we show that boundary states may be recovered in this limit and, furthermore, the description through closed string (perturbative) degrees of freedom collapses. We also show how the thermal properties of branes and closed strings could be described by this model, and it requires that dissipative effects be taken into account. Some remarks on the open string description of thermal D-branes are finally mentioned.

Mauricio Sturla (Univ. Nacional de La Plata)

Wormhole solutions to Hořava gravity

Recently, a power counting renormalizable non-relativistic theory of gravity was proposed by Hořava (arXiv:0901.3775 [hep-th]). Since then, a lot of work has been made on the subject. Some spherically symmetric solutions have been found, and interesting cosmological implications have appeared. In particular this theory has the peculiarity of having bounces in the cosmological solutions without the presence of exotic matter. In this context, it seems natural to wonder whether small wormholes in vacuum could be supported without requiring the addition of any exotic matter. In this talk I would like to present vacuum transversables wormholes solutions, supported by this theory, that we have found in collaboration with Nicolás Grandi y Marcelo Botta-Cantcheff, arXiv:0906.0582 [hep-th].