Boson Stars in Higher Derivative Gravity

TL;DR

This paper constructs and analyzes boson star solutions within four-dimensional scalar-Gauss-Bonnet gravity, revealing their increased compactness, stability conditions, and distinctive mass-radius and mass-frequency relationships compared to standard models.

Contribution

It introduces boson star solutions in scalar-Gauss-Bonnet gravity with non-minimal coupling, highlighting their unique properties and stability regimes not seen in Einstein gravity.

Findings

Boson stars are more compact and slightly massive in scalar-Gauss-Bonnet gravity.

Negative binding energy indicates intrinsic stability for certain coupling ranges.

Mass-radius and mass-frequency relations differ from those in Einstein gravity.

Abstract

In this paper, we have constructed Boson star (BS) solutions in four dimensional scalar-Gauss-Bonnet (sGB) theory. In order to have non-trivial effect from Gauss-Bonnet term, we invoked non-minimal coupling between a complex scalar field and the Gauss-Bonnet term with a coupling parameter, $\alpha$. We show that the scalar field can no longer take arbitrary value at the center of the star. Furthermore, boson-stars in our higher derivative theory turn out to be slightly massive but much more compact than those in the usual Einstein's gravity. Interestingly, we found that for $\alpha<-0.4$ and $\alpha>0.8$, binding energy for all possible boson stars is always negative. This implies that these stars are intrinsically stable against the decay by dispersion. We also present the mass-radius and mass-frequency curves for boson-star and compare them with other compact objects in gravity models derived from Gauss-Bonnet term.