On Unitary Evolution in Quantum Field Theory in Curved Spacetime
Abstract
We investigate the question of unitarity of evolution between hypersurfaces in quantum field theory in curved spacetime from the perspective of the general boundary formulation. Unitarity thus means unitarity of the quantum operator that maps the state space associated with one hypersurface to the state space associated with the other hypersurface. Working in KleinGordon theory, we find that such an evolution is generically unitary given a onetoone correspondence between classical solutions in neighborhoods of the respective hypersurfaces. This covers the case of pairs of Cauchy hypersurfaces, but also certain cases where hypersurfaces are timelike. The tools we use are the Schroedinger representation and the Feynman path integral.
 Publication:

The Open Nuclear & Particle Physics Journal
 Pub Date:
 August 2011
 DOI:
 10.2174/1874415X01104010013
 arXiv:
 arXiv:0912.0556
 Bibcode:
 2011ONPPJ...4...13C
 Keywords:

 High Energy Physics  Theory;
 General Relativity and Quantum Cosmology
 EPrint:
 12 pages, LaTeX + revtex4