We study the evolution of nonspherical bubbles which arise in the theory of a real scalar field that has nondegenerate ground states. A calculational framework to study radial perturbations to the evolution of spherical shells of domain wall is presented. We focus on the (classical) evolution of true-vacuum bubbles which nucleate in a sea of false vacuum in a first-order phase transition, e.g., as in old or extended inflation (we work in the zero-temperature, zero-gravity limit). As the bubbles evolve, perturbations with nonzero initial velocity and low angular wave numbers grow initially and then freeze out; perturbations with high wave number oscillate about the unperturbed state and eventually decay. Perturbations with finite initial amplitude and zero initial velocity quickly decay for all wave numbers. Applications of our work to closed-surface domain walls (which have recently been invoked to explain large-scale structures in cosmology) are also discussed.

• Received 10 August 1989

DOI:https://doi.org/10.1103/PhysRevD.41.347