A note on the hidden conformal structure of non-extremal black holes

We study, following Bertini et al. [1], the hidden conformal symmetry of the massless Klein-Gordon equation in the background of the general, charged, spherically symmetric, static black-hole solution of a class of d-dimensional Lagrangians which includes the relevant parts of the bosonic Lagrangian of any ungauged supergravity. We find that a hidden SL(2,R) symmetry appears at the near event- and Cauchy-horizon limits. We extend the two sl(2) algebras to two full Witt algebras (Virasoro algebras with vanishing central charges). We comment on the implications of the possible existence of an associated quantum conformal field theory.