  An interacting scalar field theory in de Sitter space is non-renormalizable
for a generic alpha-vacuum state. This pathology arises since the usual
propagator used allows for a constructive interference among propagators in
loop corrections, which produces divergences that are not proportional to
standard counterterms. This interference can be avoided by defining a new
propagator for the alpha-vacuum based on a generalized time-ordering
prescription. The generating functional associated with this propagator
contains a source that couples to the field both at a point and at its
antipode. To one loop order, we show that a set of theories with very general
antipodal interactions is causal and renormalizable.
