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, 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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