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

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 $V_3(\varphi )=\frac{m^2}{2}{\varphi }^2-\mu {\varphi }^3+\lambda {\varphi }^4$ 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.

Comments: 10 pages, 13 figures