Speaker
Description
Black hole perturbations in general relativity are typically governed by Heun-type differential equations, whose associated connection problem has remained largely unexplored for many years. Recent developments in 2D CFT, however, have led to partial progress on this long-standing issue, allowing for a more transparent treatment of the associated spectral problems, in particular the computation of quasinormal modes.
In this talk, I will review the basics of the Heun connection problem and apply these results to the computation of purely-imaginary quasinormal modes in the Vaidya spacetime (i.e., an accreting black hole). I will show that the analytic computation agrees with both numerical results and with those obtained by approximating the perturbation equation in its hypergeometric limits. In the latter case, we recover the same leading-order formula, together with additional subleading corrections.