In this presentation we review our work on Abelian Maxwell-Chern-Simons theory in three-dimensional AdS black brane backgrounds, with both integer and non-integer Chern-Simons coupling. Such theories can be derived from several string theory construc
tions, and we found exact solutions in the low frequency, low momentum limit (omega, k << T, the hydrodynamic limit). Our results are translated into correlation functions of vector operators in the dual strongly coupled 1+1-dimensional quantum field theory with a chiral anomaly at non-zero temperature T, via the holographic correspondence. The applicability of the hydrodynamic limit is discussed, together with the comparison between an exact field theoretic computation and the found holographic correlation functions in the conformal case.
We study large N orbifold equivalences involving three-dimensional N=3 and N=4 supersymmetric quiver Chern-Simons-matter theories. The gravity dual of the N=3 Chern-Simons-matter theory is described by AdS4xM7 where the tri-Sasaki manifold M7 is know
n as the Eschenburg space. We find evidence that a large N orbifold equivalence for the N=4 case continues from the M-theory limit to the weak-coupling limit. For the N=3 case, we find consistent large N equivalences involving a projection changing the nodes of the gauge groups, and also for a projection changing Chern-Simons levels where for the latter projection, the BPS monopole operators behave as expected in large N equivalence. For both cases we show, using the gravity dual, that the critical temperature of the confinement/deconfinement transition does not change and the entropy behaves as expected under the orbifold equivalence. We show that large N orbifold equivalence changing Chern-Simons levels can be explained using the planar equivalence in the mirror dual.
We consider a new large-N limit, in which the t Hooft coupling grows with N. We argue that a class of large-N equivalences, which is known to hold in the t Hooft limit, can be extended to this very strongly coupled limit. Hence this limit may lead to
a new way of studying corrections to the t Hooft limit, while keeping nice properties of the latter. As a concrete example, we describe large-N equivalences between the ABJM theory and its orientifold projection. The equivalence implies that operators neutral under the projection symmetry have the same correlation functions in two theories at large-N. Usual field theory arguments are valid when t Hooft coupling $lambdasim N/k$ is fixed and observables can be computed by using a planar diagrammatic expansion. With the help of the AdS/CFT correspondence, we argue that the equivalence extends to stronger coupling regions, $Ngg k$, including the M-theory region $Ngg k^5$. We further argue that the orbifold/orientifold equivalences between certain Yang-Mills theories can also be generalized. Such equivalences can be tested both analytically and numerically. Based on calculations of the free energy, we conjecture that the equivalences hold because planar dominance persists beyond the t Hooft limit.
We compute the holographic entanglement entropy in the gravity with higher curvature terms dual to d=4 N=2 SCFTs in F-theory using the method proposed in arXiv:1011.5819. The log term of this entanglement entropy reproduces the A-type anomaly of the
dual SCFTs in F- theory using the gravity dual with the higher derivative term, which, using the field redefinition, can be transformed to the Gauss-Bonnet term in the subleading order of a derivative expansion. Our analysis shows that the 1/N^2 correction for the central charges should be produced from the gravity including higher derivative terms up to curvature squared terms. To obtain consistent results, we discuss the holographic c-theorem.
