  We consider 1/2 BPS excitations of AdS(5)xS(5) geometries in type IIB string
theory that can be mapped into free fermion configurations according to the
prescription of Lin, Lunin and Maldacena (LLM). It is shown that whenever the
fermionic probability density exceeds one or is negative, closed timelike
curves appear in the bulk. A violation of the Pauli exclusion principle in the
phase space of the fermions is thus intimately related to causality violation
in the dual geometries.
