Scalarized non-topological neutron stars in multi-scalar Gauss-Bonnet gravity

TL;DR

This paper constructs new non-topological neutron star solutions in multi-scalar Gauss-Bonnet gravity, showing how scalarization leads to energetically favorable configurations that differ from general relativity.

Contribution

It introduces novel scalarized neutron star solutions in multi-scalar Gauss-Bonnet gravity with a detailed analysis of their stability and bifurcation from GR solutions.

Findings

Scalarized solutions bifurcate from trivial solutions at certain parameters.

Nontrivial scalarized solutions are energetically more favorable than GR solutions.

Solutions are characterized by the number of scalar field zeros.

Abstract

In the present paper we construct novel non-topological, spontaneously scalarized neutron stars in multi-scalar Gauss-Bonnet gravity with maximally symmetric target space, and nontrivial map $\varphi:spacetime \rightarrow target\ space$. The theory is characterized by the fact that for some classes of coupling functions the field equations allow solutions with trivial scalar field, which coincide with the general relativistic ones. For a certain range of parameters those solutions lose stability and new branches of solutions with nontrivial scalar field bifurcate from the trivial branch. For a given set of parameters, those branches are characterized by the number of zeros of the scalar field, and they are energetically more favorable than the general relativistic ones.