Nonminimally coupled scalar field in teleparallel gravity: boson stars

Abstract

We study the nonminimally coupled complex scalar field within the framework of teleparallel gravity. Coupling of the field nonminimally to the torsion scalar destroys the Lorentz invariance of the theory in the sense that the resulting equations of motion depend on the choice of a tetrad. For the assumed static spherically symmetric spacetime, we find a tetrad which leads to a self-consistent set of equations, and we construct the self-gravitating configurations of the scalar field-boson stars. The resulting configurations develop anisotropic principal pressures and satisfy the dominant energy condition. An interesting property of the configurations obtained with sufficiently large field-to-torsion coupling constant is the outwardly increasing energy density, followed by an abrupt drop towards the usual asymptotic tail. This feature is not present in the boson stars with the field minimally or nonminimally coupled to the curvature scalar, and therefore appears to be a torsion-only effect.

Photon sphere and perihelion shift in weak f(T) gravity

“…In addition, some regular black hole solutions (perturbatively and exact) have been found correctly in [14,15]. When one considers matter, there are some works which have studied the possibility of constructing stars or wormhole solutions in different teleparallel theories of gravity [16][17][18][19][20][21][22][23][24]. Overall the issue of finding exact spherically symmetric solutions in f (T )-gravity is still an open problem.…”

Exact Spherically Symmetric Solutions in Modified Teleparallel Gravity

“…Still, there are few exact spherically symmetric solutions in modified Teleparallel gravity. Different authors have studied stars and wormholes in different Teleparallel theories [27,[31][32][33][34]. In [20,35], the authors found some vacuum exact solutions in f (T ) gravity, however, they imposed T = constant, which is nothing but consider GR plus a cosmological constant.…”

Spherically symmetric vacuum in covariant F(T)=T+α2T2+DeBenedictis1, Ilijić2 2016Phys. Rev. D6810612View full textAdd to dashboardCite

“…The action for the extended theory can be written as 1 where L m represents the matter Lagrangian density, κ = 8π, h a µ is the tetrad, and F (T ) is a function of the torsion scalar, T . When F (T ) is linear in T , and the matter coupling is minimal [2], [3], the theory is equivalent to general relativity. However, when F (T ) possesses terms non-linear in T the theory can be radically different from the corresponding F (R) theory.…”