This series consists of talks in the area of Superstring Theory.
The exact boundary states for the rolling D-brane solution in two-dimensional black hole systems will be presented.I will study the physical significance of the solution in relation to the ``tachyon-radion correspondence\" and the ``black hole - string transition\". When the alpha\' corrections become larger, when at the same time the Hawking temperature coincide with the Hagedorn temperature, the phase transition occurs and the physics changes drastically. It also suggests the universal feature of the decaying D-brane and its failure in the strong quantum regime.
I will discuss some ambiguities involved in using the AdS/CFT correspondence
to calculate the ultra-relativistic jet quenching parameter for quarks moving in
an N=4 super Yang-Mills thermal bath. Along the way, I will investigate the behavior of various string configurations on a five-dimensional AdS black hole
background.
TBA
In string compactifications, Kahler metrics for chiral matter fields are an essential prerequisite for the computation of soft supersymmetry breaking terms. I describe new techniques for computing these in Calabi-Yau string compactifications. This involves deducing the modular behaviour of the Kahler metric from that of the physical Yukawa couplings. Using these techniques I derive Kahler metrics for both KKLT and large-volume models. For the latter case, I discuss two applications.
TBA
Studies of ${cal N}=4$ super Yang Mills operators with large R-charge have shown that, in the planar limit, the problem of computing their dimensions can be viewed as a certain spin chain. These spin chains have fundamental ``magnon\'\' excitations which obey a dispersion relation that is periodic in the momentum of the magnons. This result for the dispersion relation was also shown to hold at arbitrary \'t Hooft coupling. Here we identify these magnons on the string theory side and we show how to reconcile a periodic dispersion relation with the continuum worldsheet description.