Fragileness of Exact I-ball/Oscillon

TL;DR

This paper investigates the stability of exact I-ball/oscillon configurations in scalar field theory, revealing their classical stability but susceptibility to perturbations, which leads to their eventual breakup, confirmed through simulations.

Contribution

It demonstrates that exact I-ball/oscillon solutions are classically stable yet fragile against small perturbations, highlighting their limited longevity in realistic scenarios.

Findings

Exact I-ball/oscillon is stable in classical theory.

Small perturbations can destabilize the exact I-ball/oscillon.

Classical lattice simulations confirm the fragileness of the exact I-ball/oscillon.

Abstract

I-ball/oscillon is a soliton-like oscillating configuration of a real scalar field which lasts for a long time. I-ball/oscillon is a minimum energy state for a given adiabatic invariant, and its approximate conservation guarantees the longevity. In this paper, we examine the stability of a special type of I-ball/oscillon, the "exact" I-ball/oscillon, whose adiabatic invariant is exactly conserved. We show that the exact I-ball/oscillon is stable in classical field theory, but not stable against small perturbations depending on the value of its adiabatic invariant. Accordingly, the exact I-ball/oscillon breaks up in the presence of the fluctuations with corresponding instability modes. We also confirm the fragileness of the exact I-ball/oscillon by the classical lattice simulation.