Dirichlet p-branes in the background of pp waves are constructed using the massive Green-Schwarz worldsheet action for open strings. These branes are localized at the origin and only for p = 7, 5, 3 preserve half the supersymmetries. The spectrum of the brane theory is analyzed and is found to be in agreement with the spectrum of the small fluctuations of the world-volume super Yang-Mills theory in this background. These branes are expected to correspond to objects that are nonperturbative in N in the dual gauge theory.

We investigate the attractor mechanism for spherically symmetric extremal black holes in a theory of general R 2 gravity in 4-dimensions, coupled to gauge fields and moduli fields. For the general R 2 theory, we look for solutions which are analytic near the horizon, show that they exist and enjoy the attractor behavior. The attractor point is determined by extremization of an effective potential at the horizon. This analysis includes the backreaction and supports the validity of non-supersymmetric attractors in the presence of higher derivative interactions. To include a wider class of solutions, we continue our analysis for the specific case of a Gauss-Bonnet theory which is nontopological, due to the coupling of Gauss-Bonnet terms to the moduli fields. We find that the regularity of moduli fields at the horizon is sufficient for attractor behavior. For the non-analytic sector, this regularity condition in turns implies the minimality of the effective potential at the attractor point.

By taking the interacting spinor-scalar theory on the AdS d+1 space we calculate the boundary CFT correlation functions using AdS/CFT correspondence.

We study type IIA superstring theory on a PP-wave background with 24 supercharges. This model can exactly be solved and then quantized. The open string in this PP-wave background is also studied. We observe that the theory has supersymmetric Dp-branes for p = 2, 4, 6, 8.

A black brane solution to a Gauss-Bonnet massive gravity is introduced. In the context of AdS/CFT correspondence, the viscosity to entropy ratio is found by the Green-Kubo formula. The result indicates violation of the well-known KSS bound as expected in a higher derivative theory. Setting mass zero gives back the known viscosity to entropy ratio dependent on the Gauss-Bonnet coupling, while without Gauss-Bonnet term, a nonzero mass parameter doesn't contribute to the ratio which saturates the bound of 1 4π .