Abstract
In the upper and lower quadrants of flat spacetime, (±T>‖X‖) it is possible to introduce a system of coordinates in which the metric is explicitly time dependent. The conventional interpretation of quantum field theory, based on a Fock basis, cannot be implemented in a natural fashion in such coordinates. This difficulty suggests that quantum theory is covariant only for a subset of the coordinate transformations which are allowed in the classical theory.
- Received 27 December 1989
DOI:https://doi.org/10.1103/PhysRevLett.64.2471
©1990 American Physical Society
