Unitarity in the Schroedinger Formalism of QFT in Curved Space-Time
We review the general quantization of scalar fields in curved space-times in the Schroedinger formalism and discuss the determination of the ground-state. By explicitly computing the norm of the ground-state wave functional, we give an argument for the instability of the ground-state of a QFT in a semi-classical space-time of Bianchi-type I. We find that this norm is, in general, time-dependent, and conclude that the ground-state evolution is not unitary.
hep-th↗