Boson Stars in a Theory of Complex Scalar Field coupled to Gravity

TL;DR

This paper investigates boson star solutions in a complex scalar field theory coupled to gravity, exploring their properties, types, and existence domains under various potential and cosmological constant conditions.

Contribution

It introduces a new potential combining quadratic and linear terms, analyzing boson star solutions with both ball-like and shell-like charge densities, expanding understanding of scalar field configurations in gravity.

Findings

Boson stars exhibit two types: ball-like and shell-like charge densities.

Existence domains depend on parameters and cosmological constant values.

Solutions are similar to those in V-shaped scalar potential theories.

Abstract

We study boson stars in a theory of complex scalar field coupled to Einstein gravity with the potential: $V(|\Phi|) := m^{2} |\Phi|^2 +2 \lambda |\Phi|$ (where $m^2$ and $\lambda$ are positive constant parameters). This could be considered either as a theory of massive complex scalar field coupled to gravity in a conical potential or as a theory in the presence of a potential which is an overlap of a parabolic and a conical potential. We study our theory with positive as well as negative values of the cosmological constant $\Lambda$. Boson stars are found to come in two types, having either ball-like or shell-like charge density. We have studied the properties of these solutions and have also determined their domains of existence for some specific values of the parameters of the theory. Similar solutions have also been obtained by Hartmann, Kleihaus, Kunz, and Schaffer, in a V-shaped scalar potential.