Abstract

Necessary conditions are proposed for the admissibility of singular classical solutions with 3 + 1-dimensional Poincaré invariance to five-dimensional gravity coupled to scalars. Finite temperature considerations and examples from AdS/CFT support the conjecture that the scalar potential must remain bounded above for a solution to be physical. Having imposed some restrictions on naked singularities allows us to comment on a recent proposal for solving the cosmological constant problem. In AdS/CFT [1, 2, 3] (see [4] for a review), bulk geometries which are only asymptotically AdS5 near the timelike boundary are dual to relevant deformations of the CFT or to non-conformal vacua. Far from the timelike boundary, various singularities might arise. There must be some restrictions on the type of singularity which is allowed: for