Decay of Scalar Condensation in Quantum Field Theory

Understand

We consider decay processes of scalar-field condensation in the framework of well-established quantum field theory.

• We postulate that the quantum state corresponding to the scalar-field condensation is so-called coherent state with discussing the validity of such a treatment.
• We show that, by using the unitarity relation of the scattering matrix, decay rate of the coherent state is systematically calculated.
• We apply our procedure to derive explicit formulae of decay rates for two cases: (i) we study the case where the scalar condensation decays into a pair of scalar particles and show that our formalism reproduces the results obtained from the parametric-resonance analysis, and (ii) we also calculate the decay rate when the coherent state decays via anomaly.