We show that, in a relativistic quantum theory in which the mass shell is not sharp, and positive and negative energy states are admissable, causal propagation is possible, and Hegerfeldt's theorem can be avoided. The conditions under which this is true have simple physical interpretation.
|Number of pages||7|
|Journal||Foundations of Physics Letters|
|State||Published - Jun 1991|
- causal propagation
- relativistic quantum mechanics