40 research outputs found
Influence of interactions on particle production induced by time-varying mass terms
We have investigated effects of interaction terms on non-perturbative
particle production. It is well known that time-varying masses induce abundant
particle production. In this paper we have shown that it is possible to induce
particle production even if the mass term of a particle species is not varying
in time. Such particles are produced through the interactions with other
fields, whose mass terms are varying due to a time-dependent background. The
necessary formalism has been introduced and analytic and numerical calculations
have been performed in a simple but illustrative model. The rather general
result is that the amount of produced particles without time-dependent masses
can be comparable with the particle density produced directly by the varying
background if the strength of interaction terms is reasonably large.Comment: 15 pages, 4 figure