String theory

• Applicant: Professor Babak Haghighat, Ph.D.
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2010 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 174473166

According to Bekenstein and Hawking the entropy of black holes is proportional to the area of their horizon. Within string theory supersymmetric black holes are modeled by certain “D-brane” configurations. The partition function of such configurations can be computed with the help of the topological string and the resulting microscopic entropy formula is equivalent to the semi classical macroscopic one in the limit of large charges. However, the number of stable configurations corresponding to a certain macroscopic state is equivalent to the number of so called “BPS states” which changes upon crossing “walls of marginal stability” in moduli space. One of the aims of my research is to derive such “wall-crossing” formulas for local Calabi-Yau geometries.Another major goal of my project is connected to “F-Theory” which is a geometrization of type IIB string theory encoding all non-perturbative aspects in geometry. Recently, it has been shown that F-Theory also bears very interesting phenomenological applications in the field of GUT model building. From the mathematics point of view four dimensional physics arises from F-Theory after compactification on “Calabi-Yau fourfolds”. Concerning my own research as a DFG fellow I intend to compute brane- and flux-superpotentials for certain fourfolds and analyze the implications of my results for the duality to the heterotic string and for phenomenologically interesting models.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Cumrun Vafa