Gravitational theories with multiple scalar fields coupled to the metric and each other - a natural extension of the well studied single-scalar-tensor theories - are interesting phenomenological frameworks to describe deviations from general relativity in the strong-field regime. In these theories, the N-tuple of scalar fields takes values in a coordinate patch of an N-dimensional Riemannian target-space manifold whose properties are poorly constrained by weak-field observations. Here we introduce for simplicity a non-trivial model with two scalar fields and a maximally symmetric target-space manifold. Within this model we present a preliminary investigation of spontaneous scalarization for relativistic, perfect fluid stellar models in spherical symmetry. We find that the scalarization threshold is determined by the eigenvalues of a symmetric scalar-matter coupling matrix, and that the properties of strongly scalarized stellar configurations additionally depend on the target-space curvature radius. In preparation for numerical relativity simulations, we also write down the 3 + 1 decomposition of the field equations for generic tensor-multi-scalar theories.

Horbatsch, M., Silva, H., Gerosa, D., Pani, P., Berti, E., Gualtieri, L., et al. (2015). Tensor-multi-scalar theories: relativistic stars and 3+1 decomposition. CLASSICAL AND QUANTUM GRAVITY, 32(20) [10.1088/0264-9381/32/20/204001].

Tensor-multi-scalar theories: relativistic stars and 3+1 decomposition

Gerosa D;
2015

Abstract

Gravitational theories with multiple scalar fields coupled to the metric and each other - a natural extension of the well studied single-scalar-tensor theories - are interesting phenomenological frameworks to describe deviations from general relativity in the strong-field regime. In these theories, the N-tuple of scalar fields takes values in a coordinate patch of an N-dimensional Riemannian target-space manifold whose properties are poorly constrained by weak-field observations. Here we introduce for simplicity a non-trivial model with two scalar fields and a maximally symmetric target-space manifold. Within this model we present a preliminary investigation of spontaneous scalarization for relativistic, perfect fluid stellar models in spherical symmetry. We find that the scalarization threshold is determined by the eigenvalues of a symmetric scalar-matter coupling matrix, and that the properties of strongly scalarized stellar configurations additionally depend on the target-space curvature radius. In preparation for numerical relativity simulations, we also write down the 3 + 1 decomposition of the field equations for generic tensor-multi-scalar theories.
Articolo in rivista - Articolo scientifico
black holes; gravity; modified theories; neutron stars;
black holes, gravitational waves, general relativity, relativistic astrophysics
English
2015
32
20
204001
none
Horbatsch, M., Silva, H., Gerosa, D., Pani, P., Berti, E., Gualtieri, L., et al. (2015). Tensor-multi-scalar theories: relativistic stars and 3+1 decomposition. CLASSICAL AND QUANTUM GRAVITY, 32(20) [10.1088/0264-9381/32/20/204001].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/325479
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