Freiburg 2008 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 21: Quantenfeldtheorie I
T 21.3: Vortrag
Donnerstag, 6. März 2008, 17:20–17:35, KGI-HS 1016
AdS/CFT with Flavour in Electric and Magnetic Kalb-Ramond Fields — •René Meyer1, Johanna Erdmenger1, and Jonathan P. Shock2,3 — 1Max-Planck-Institute für Physik, München, Deutschland — 2Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, People’s Republic of China — 3Departamento de Fisica de Particulas, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
We investigate gauge/gravity duals with flavour and at finite temperature for which pure-gauge Kalb-Ramond B fields are turned on in the background, into which a D7 brane probe is embedded. Supersymmetry is broken for the fundamental matter in the dual gauge theory. We consider two cases: A magnetic B field in two spatial directions of four-dimensional Minkowski space, and an electric one, with B field in the time direction and one spatial Minkowski direction. In the former case, we find that the B field has a stabilizing effect on the mesons, a chiral phase transition, and that spontaneous chiral symmetry breaking occurs for a sufficiently large value of the B field. In the electric case, it is necessary to switch on a gauge field on the D7 brane to ensure stability of the system, corresponding to finite baryon number density and chemical potential. We find that the D7 branes undergo a topological transition, which we interpret as a chiral transition from a mesonic phase to a phase in which the mesons dissociate. The electric B field has a destabilizing effect on the mesons, but no spontaneous chiral symmetry breaking occurs in this case. For weak fields and at zero temperature, we find a mass shift similar to the Stark effect.