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Instability of compact stars with a nonminimal scalar-derivative coupling
- Source :
- Journal of Cosmology and Astroparticle Physics. 2021:008-008
- Publication Year :
- 2021
- Publisher :
- IOP Publishing, 2021.
-
Abstract
- For a theory in which a scalar field $\phi$ has a nonminimal derivative coupling to the Einstein tensor $G_{\mu \nu}$ of the form $\phi\,G_{\mu \nu}\nabla^{\mu}\nabla^{\nu} \phi$, it is known that there exists a branch of static and spherically-symmetric relativistic stars endowed with a scalar hair in their interiors. We study the stability of such hairy solutions with a radial field dependence $\phi(r)$ against odd- and even-parity perturbations. We show that, for the star compactness ${\cal C}$ smaller than $1/3$, they are prone to Laplacian instabilities of the even-parity perturbation associated with the scalar-field propagation along an angular direction. Even for ${\cal C}>1/3$, the hairy star solutions are subject to ghost instabilities. We also find that even the other branch with a vanishing background field derivative is unstable for a positive perfect-fluid pressure, due to nonstandard propagation of the field perturbation $\delta \phi$ inside the star. Thus, there are no stable star configurations in derivative coupling theory without a standard kinetic term, including both relativistic and nonrelativistic compact objects.<br />Comment: 17 pages, 8 figures, published version
- Subjects :
- High Energy Physics - Theory
Physics
Field (physics)
Star (game theory)
Scalar (mathematics)
FOS: Physical sciences
Astronomy and Astrophysics
General Relativity and Quantum Cosmology (gr-qc)
Kinetic term
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
Neutron star
Einstein tensor
symbols.namesake
High Energy Physics - Phenomenology (hep-ph)
High Energy Physics - Theory (hep-th)
symbols
Scalar field
Laplace operator
Mathematical physics
Subjects
Details
- ISSN :
- 14757516
- Volume :
- 2021
- Database :
- OpenAIRE
- Journal :
- Journal of Cosmology and Astroparticle Physics
- Accession number :
- edsair.doi.dedup.....0b7cf113ff09307a942ac58f5ed53dbb