Quantum field theory in a gravitational shock wave background

Abstract

A scalar massless non-interacting quantum field theory on an arbitrary gravitational shock wave background is exactly solved. S-matrix and expectation values of the energy-momentum tensor are computed for an arbitrary polarized sourceless gravitational shock wave and for a homogeneous infinite planar shell shock wave, all performed in any number of space-time dimensions. Expectation values of the energy density in scattering states exhibit a singularity which lies exactly at the location of the curvature singularity found in the infinite shell collision.