We discuss massive scalar perturbations of a two-dimensional dilaton black
hole. We employ a Pauli-Villars reqularization scheme to calculate the effect
of the scalar perturbation on the Bekenstein-Hawking entropy. By concentrating
on the dynamics of the scalar field near the horizon, we argue that quantum
effects alter the effective potential. We calculate the two-point function
explicitly and show that it exhibits Poincare recurrences.Comment: 11 page