COVARIANT ANOMALIES, HORIZONS AND HAWKING RADIATION

Abstract

Hawking radiation is obtained from anomalies resulting from a breaking of diffeomorphism symmetry near the event horizon of a black hole. Such anomalies, manifested as a nonconservation of the energy–momentum tensor, occur in two different forms — covariant and consistent. The crucial role of covariant anomalies near the horizon is revealed, since this is the only input required to obtain the Hawking flux, thereby highlighting the universality of this effect. A brief description of the application of this method to obtain thermodynamic entities like entropy or temperature is provided.