Cosmic bubble and domain wall instabilities I: parametric amplification of linear fluctuations

Understand

This is the first paper in a series where we study collisions of nucleated bubbles taking into account the effects of small initial (quantum) fluctuations in a fully 3+1-dimensional setting.

• In this paper, we consider the evolution of linear fluctuations around highly symmetric though inhomogeneous backgrounds.
• We demonstrate that a large degree of asymmetry develops over time from tiny fluctuations superposed upon planar and SO(2,1) symmetric backgrounds.
• These fluctuations arise from zero-point vacuum oscillations, so excluding them by enforcing a spatial symmetry is inconsistent in a quantum treatment.