Orateur
Description
Abstract: The thermodynamic properties of black holes -- temperature,
entropy and radiation rates -- are usually associated with the
presence of a horizon. We argue that any Extremely Compact Object
(ECO) must have the {\it same} thermodynamic properties. Quantum
fields just outside the surface of an ECO have a large negative
Casimir energy similar to the Boulware vacuum of black holes. If the
thermal radiation emanating from the ECO does not fill the
near-surface region at the local Unruh temperature, then we find that
no solution of gravity equations is possible. In string theory, black
holes microstates are horizonless quantum objects called fuzzballs
that are expected to have a surface $\sim l_p$ outside $r=2GM$; thus
the information puzzle is resolved while preserving the semiclassical
thermodynamics of black holes.
