Detlev Buchholz, Martin Florig, Stephen J. Summers
Hawking-Unruh Temperature and Einstein Causality in Anti-de Sitter Space-Time 
(25K, Latex)

ABSTRACT.  If the vacuum is passive for uniformly accelerated observers in
anti-de Sitter space-time ({\em i.e.} cannot be used by them to
operate a {\em perpetuum mobile}), they will (a) register a unique
value of the Hawking--Unruh temperature and (b) find that products of
observables which are localized in complementary wedge--shaped regions
necessarily commute with each other in the vacuum state.  Thus the
stability properties of the vacuum induce a ``geodesic causal
structure'' on this space-time which seems incompatible with true
interaction.