Detlev Buchholz, Jens Mund and Stephen J. Summers
Transplantation of Local Nets and Geometric Modular Action on 
Robertson-Walker Space-Times
(72K, .tar file with one latex file and an .eps figure)

ABSTRACT.  A novel method of transplanting algebras of observables 
from de Sitter space to a large class of Robertson--Walker 
space--times is exhibited. It allows one to establish the existence 
of an abundance of local nets on these spaces which comply with a 
recently proposed condition of geometric modular action. The 
corresponding modular symmetry groups appearing in these examples 
also satisfy a condition of modular stability, which has been suggested 
as a substitute for the requirement of positivity of the energy in 
Minkowski space. 
Moreover, they exemplify the conjecture that the modular symmetry 
groups are generically larger than the isometry and conformal groups 
of the underlying space--times.