String theory and black holes

Abstract

This thesis aims to make precise the microscopic understanding of Hawking radiation from the D1/D5 black hole. We present an explict construction of all the N=(4,4) SCFT on the symmetric product T4/S(Q1Q5). An investigation of the symmerties of this SCFT enables us to make a one-to-one correspondence beween the supergravity moduli and the marginal opeerators of the SCFT. We analyse the gauge theory dynamics of the splitting of the D1/D5 system into subsystems and show that it agrees with supergravity. We have shown that the fixed scalars of the D1/D5 system couple only to (2, 2) operators thus removing earlier discrepancies between D-brane calculations and semiclassical calculations. The absorption cross-section of the minimal scalars is determined from first principles upto a propotionality constant. We show that the absorption cross-section of the minimal scalars computed in supergravity and the SCFT is independent of the moduli.