Perturbations of Q-balls: from spectral structure to radiation pressure

TL;DR

This paper studies the spectral properties and radiation interactions of Q-balls in a 1+1D scalar field, revealing decay mechanisms and conditions for negative radiation pressure.

Contribution

It provides new insights into the relaxation dynamics and radiation pressure effects on Q-balls, including the role of normal modes and nonlinear couplings.

Findings

Decay of normal modes dominates relaxation

Q-balls can experience negative radiation pressure

Long-lasting quasi-normal modes influence stability

Abstract

We investigate Q-balls in a 1+1 dimensional complex scalar field theory. We find that the relaxation of a squashed Q-ball is dominated by the decay of a normal mode through nonlinear coupling to scattering modes and a long-lasting quasi-normal mode. We also study how these Q-balls behave when exposed to scalar radiation, finding that for certain conditions they can experience negative radiation pressure.