CASIMIR EFFECT IN QUANTUM FIELD-THEORY

A new conceptual foundation for renormalizing T on locally flat space-time to obtain the so-called Casimir effect is presented. The Casimir ground state is viewed locally as a (nonvacuum) state on Minkowski space-time and the expectation value of the normal-ordered T is taken. The same ideas allow us to treat, for the first time, self-interacting fields for arbitrary mass in perturbation theory using traditional flat-space-time renormalization theory. First-order results for zero-mass 4 theory agree with those recently announced by Ford. We point out the crucial role played by the simple renormalization condition that the vacuum expectation value of T must vanish in Minkowski space-time, and in a critical discussion of other approaches, we clarify the question of renormalization ambiguities for T in curved space-times. In an Appendix, we show how the Casimir effect arises in the C*-algebra approach to quantum field theory. © 1979 The American Physical Society.