Supersymmetric black holes are characterized by a large number of degenerate ground states. We argue that these black holes, like other quantum mechanical systems with such a degeneracy, are subject to a phenomenon which is called the geometric or Berry’s phase: under adiabatic variations of the background values of the supergravity moduli, the quantum microstates of the black hole mix among themselves. We present a simple example where this mixing is exactly computable, that of small supersymmetric black holes in 5 dimensions.

• Received 23 May 2009

DOI:https://doi.org/10.1103/PhysRevLett.103.131301