Collision Dynamics of False-Vacuum Oscillons

TL;DR

This paper investigates the collision behavior of localized oscillons in scalar field theories with false vacua, revealing complex interactions, resonance phenomena, and potential phase transitions.

Contribution

It introduces a detailed analysis of oscillon collision dynamics in two classes of scalar theories, including force decay, resonance windows, and phase transition mechanisms.

Findings

Force between oscillons decays exponentially with separation.

Resonance windows similar to kink-antikink collisions are observed.

High-energy oscillons can induce phase transitions to the true vacuum.

Abstract

We study the collision dynamics of localized oscillons in two classes of $(1+1)$-dimensional scalar field theories with metastable false vacua, a normal class with a positive quartic self-interaction term and an inverted class with a negative quartic term. We construct small-amplitude oscillon solutions around the false vacuum using the Fodor {\emph{et al.}} expansion, and show that the force between oscillons decays exponentially at large separation, with a strength modulated by their relative phase. Numerical simulations of two-oscillon collisions exhibit reflection, crossing, and formation of excited oscillons. Resonance windows occur, similar to those found in kink-antikink collisions. In the normal theory, if the oscillons have sufficient energy, the field can pass over a sphaleron barrier and evolve into a kink-antikink pair, initiating a phase transition to the true vacuum. We also simulate the collision of oscillons evolved from a slightly perturbed sphaleron.