Trace anomaly of dilaton-coupled scalars in two dimensions

Abstract

Conformal scalar fields coupled to the dilaton appear naturally in two-dimensional models of black hole evaporation. We show that their trace anomaly is $(1/24\ensuremath{\pi})[R\ensuremath{-}6(\ensuremath{\nabla}\ensuremath{\varphi}{)}^{2}\ensuremath{-}2\ensuremath{\square}\ensuremath{\varphi}]$. It follows that a Russo-Susskind-Thorlacius--type counterterm appears naturally in the one-loop effective action.