Dynamical evolution of boson stars in Brans-Dicke theory

TL;DR

This paper investigates the dynamical behavior of boson stars within Brans-Dicke gravity, revealing similar phenomena to general relativity and demonstrating their formation from scalar field configurations.

Contribution

It provides the first detailed analysis of boson star dynamics in Brans-Dicke theory, including formation, stability, and transition processes.

Findings

Boson stars can form from scalar field packets in BD theory.

Their dynamical evolution resembles that in general relativity.

Scalar wave emissions are comparable to GR predictions.

Abstract

We study the dynamics of a self-gravitating scalar field solitonic object (boson star) in the Jordan-Brans-Dicke (BD) theory of gravity. We show dynamical processes of this system such as (i) black hole formation of perturbed equilibrium configuration on an unstable branch; (ii) migration of perturbed equilibrium configuration from the unstable branch to stable branch; (iii) transition from excited state to a ground state. We find that the dynamical behavior of boson stars in BD theory is quite similar to that in general relativity (GR), with comparable scalar wave emission. We also demonstrate the formation of a stable boson star from a Gaussian scalar field packet with flat gravitational scalar field initial data. This suggests that boson stars can be formed in the BD theory in much the same way as in GR.