# Phase Diagrams of Charged Compact Boson Stars

## TL;DR

This paper explores the complex phase structure of charged compact boson stars and shells in a gravity-coupled scalar field theory, revealing rich bifurcation phenomena through extended 2D and 3D phase diagrams.

## Contribution

It extends previous phase diagram studies of charged boson stars to larger variable ranges, including 3D diagrams and detailed bifurcation analysis.

## Key findings

- Identification of multiple bifurcation points in phase diagrams.
- Discovery of an infinite series of bifurcation points.
- Rich physics in the phase structure of charged boson stars.

## Abstract

Compact boson stars, whose scalar field vanishes identically in the exterior region, arise in a theory involving a {\it massless} complex scalar field with a conical potential, when coupled to gravity. Their charged compact generalizations, obtained in the presence of a U(1) gauge field, exhibit further interesting features. On the one hand, charged compact boson shells can arise, whose scalar field vanishes also in the central region, while on the other hand, the domain of existence of charged compact boson stars exhibits bifurcation points. First 2D phase diagrams have been studied before. Here we extend these earlier studies to a larger range of the variables and study additional phase diagrams. We then extend these studies to obtain 3D phase diagrams and present these with a detailed discussion of their various regions with respect to the bifurcation points and argue, that there is an infinite series of such bifurcation points. Thus the theory is seen to contain rich physics in a particular domain of the phase diagrams. We also discuss the dependence of the fields on the dimensionless radial coordinate for some representative points of the phase trajectories in the phase diagrams of the theory.