Fate of thermal log type Q balls

TL;DR

This paper investigates the evolution and transformation of thermal log type Q balls in the early universe through lattice simulations, revealing their transition from thick-wall to thin-wall types and eventual dissolution, with implications for gravitational wave detection.

Contribution

It provides the first detailed lattice simulation analysis of thermal log Q ball evolution, confirming the transition to thin-wall type and the melting phenomenon as the potential diminishes.

Findings

Q balls transform from thick-wall to thin-wall types as temperature drops.

Q balls eventually dissolve when the solution disappears.

Implications for gravitational wave signals from Q-ball formation.

Abstract

We study time evolution of the $Q$ ball in thermal logarithmic potential using lattice simulations. As the temperature decreases due to the cosmic expansion, the thermal logarithmic term in the potential is eventually overcome by a mass term, and we confirm that the $Q$ ball transforms from the thick-wall type to the thin-wall type for a positive coefficient of radiative corrections to the mass term, as recently suggested. Moreover, we find that the $Q$ ball finally "melts down" when the $Q$-ball solution disappears. We also discuss the effects of this phenomenon on the detectability of gravitational waves from the $Q$-ball formation.