Seminar P. Benincasa

Speaker: 
P. Benincasa
Title: 
Universality of Holographic Phase Transitions and Holographic Quantum Liquids
Abstract: 

We explore the phase structure for defect theories in full generality
using the gauge/gravity correspondence. On the gravity side, the systems
are constructed by introducing M (probe) D(p+4-2k)-branes in a background
generated by N Dp-branes to obtain a codimension-k intersection. The dual
gauge theory is a U(N) Supersymmetric Yang-Mills theory on a
(1+p-k)-dimensional defect with both adjoint and fundamental degrees of
freedom. We focus on the phase structure in the chemical potential versus
temperature plane. We observe the existence of two universality classes
for holographic gauge theories, which are identified by the order of the
phase transition in the interior of the chemical potential/temperature
plane. Specifically, all the sensible systems with no defect show a third
order phase transition. Gauge theories on a defect with (p-1)-spatial
directions are instead characterised by a second order phase transition.
One can therefore state that the order of this phase transition is
intimately related to the codimensionality of the defect. We also discuss
the massless hypermultiplet at low temperature, where a thermodynamical
instability seems to appear for p<3. Finally, we comment on such an
instability.

Date: 
Tuesday, January 12, 2010 - 15:00 - 16:00