Oscillons in a Hot Heat Bath

Abstract

In models of real scalar fields with degenerate double-well potentials, spherically symmetric, large amplitude fluctuations away from the vacuum are unstable. Neglecting interactions with an external environment, the evolution of such configurations may entail the development of an oscillon; a localized, non-singular, time-dependent configuration which is {\it extremely} long-lived. In the present study we investigate numerically how the coupling to a heat bath influences the evolution of collapsing bubbles. We show that the existence and lifetime of the oscillon stage is extremely sensitive to how strongly the field is coupled to the heat bath. By modeling the coupling through a Markovian Langevin equation with viscosity coefficient $\gamma$, we find that for $\gamma \gtrsim 5 \times 10^{-4}m$, where $m$ is the typical mass scale in the model, oscillons are not observed.