EINSTEIN CAUSALITY IN MICROCAVITY-CONFINED TRANSVERSE QUANTUM CORRELATIONS

We demonstrate that the principle of relativistic causality is verifie d within the process of two-atom superradiance by transverse interacti on in condition of strong microcavity confinement. In particular, the effect of vacuum-confinement in transverse coupling is found to be exp ressed by an infinite series of causal step-functions. This result, ob tained exactly within the framework of non-relativistic quantum theory is found to be structurally similar to the one of the Green-function theory in relativistic QED: for this purpose we provide the first eval uation of the free-field commutator, of the chronological pairing and of the field propagator in microcavity QED. The work represents the ba sic support to an experimental causality test now in progress in our l aboratory.