Unified picture of Q-balls and boson stars via catastrophe theory

TL;DR

This paper uses catastrophe theory to analyze and unify the understanding of Q-balls and boson stars, revealing stability loss and phase relations that connect these objects.

Contribution

It extends previous flat spacetime analysis by applying catastrophe theory to both Q-balls and boson stars with specific potentials, providing a unified framework.

Findings

Stability of Q-balls is lost when metric deviations are significant.

Phase relations of charge and energy approach those of boson stars.

A unified picture of Q-balls and boson stars emerges from the analysis.

Abstract

We make an analysis of Q-balls and boson stars using catastrophe theory, as an extension of the previous work on Q-balls in flat spacetime. We adopt the potential $V_3(\phi)={m^2\over2}\phi^2-\mu\phi^3+\lambda\phi^4$ for Q-balls and that with $\mu =0$ for boson stars. For solutions with $|g^{rr}-1|\sim 1$ at its peak, stability of Q-balls has been lost regardless of the potential parameters. As a result, phase relations, such as a Q-ball charge versus a total Hamiltonian energy, approach those of boson stars, which tell us an unified picture of Q-balls and boson stars.