Approximate black holes from a variable cosmological constant

Abstract

The small or zero cosmological constant, $\Lambda$, probably results from a macroscopic cancellation mechanism of the zero-point energies. However, nearby horizon surfaces any macroscopic mechanism is expected to result in imperfect cancellations. A phenomenological description is given for the residual variable cosmological constant. In the static, spherically symmetric case it produces approximate black holes. The model describes the case of exponential decay by $\square \ln \Lambda =-3a$, were $a$ is a positive constant.

3 pages,latex,2 figures; corrected typos and existence proof