Dyon wall crossing, automorphic forms and exact black hole entropy for CHL orbifolds
by
Abhiram Kidambi(TU Vienna)
→
Europe/Berlin
313 (MPI Meeting rooms)
313
MPI Meeting rooms
Description
In this talk, I shall present the relation between the dyon (black hole) counting prescription in N = 4, d = 4 string theory from a macroscopic and microscopic point of view and the underlying number theoretic framework.
From the macroscopic perspective for N = 4 theories, these dyonic BH degeneracies are extracted via the localization technique in N = 2 superconformal gravity while from the microscopic theory, these degeneracies are encoded in the Fourier expansion of certain automorphic forms. For the case of N = 4 in which a subset of the quarter BPS dyons are prone to wall crossing, there is a number theoretic prescription for capturing the exact dyon/BH degeneracies of those quarter BPS states that do not decay via a Jacobi-Fourier decomposition and the Hardy-Ramanujan-Rademacher circle method. However, there are subtleties to this argument from the structure of walls of marginal stability in moduli space and dyonic decays at these walls. We shall go over these subtleties which are a crucial ingredient in the exact matching.
Following this, I review work in progress in the generalization of this theory to CHL orbifolds of N = 4 string theory and the extension of the number theoretic machinery of congruent subgroups of SL(2,Z).
