Boson stars in Palatini $f(mathcal{R})$ gravity. (arXiv:2103.15705v1 [gr-qc])
<a href="http://arxiv.org/find/gr-qc/1/au:+Maso_Ferrando_A/0/1/0/all/0/1">Andreu Masó-Ferrando</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Sanchis_Gual_N/0/1/0/all/0/1">Nicolas Sanchis-Gual</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Font_J/0/1/0/all/0/1">José A. Font</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Olmo_G/0/1/0/all/0/1">Gonzalo J. Olmo</a>
We explore equilibrium solutions of spherically symmetric boson stars in the
Palatini formulation of $f(mathcal{R})$ gravity. We account for the
modifications introduced in the gravitational sector by using a recently
established correspondence between modified gravity with scalar matter and
general relativity with modified scalar matter. We focus on the quadratic
theory $f(mathcal{R})=R+xi R^2$ and compare its solutions with those found in
general relativity, exploring both positive and negative values of the coupling
parameter $xi$. As matter source, a complex, massive scalar field with and
without self-interaction terms is considered. Our results show that the
existence curves of boson stars in Palatini $f(mathcal{R})$ gravity are fairly
similar to those found in general relativity. Major differences are observed
for negative values of the coupling parameter which results in a repulsive
gravitational component for high enough scalar field density distributions.
Adding self-interactions makes the degeneracy between $f(mathcal{R})$ and
general relativity even more pronounced, leaving very little room for
observational discrimination between the two theories.
We explore equilibrium solutions of spherically symmetric boson stars in the
Palatini formulation of $f(mathcal{R})$ gravity. We account for the
modifications introduced in the gravitational sector by using a recently
established correspondence between modified gravity with scalar matter and
general relativity with modified scalar matter. We focus on the quadratic
theory $f(mathcal{R})=R+xi R^2$ and compare its solutions with those found in
general relativity, exploring both positive and negative values of the coupling
parameter $xi$. As matter source, a complex, massive scalar field with and
without self-interaction terms is considered. Our results show that the
existence curves of boson stars in Palatini $f(mathcal{R})$ gravity are fairly
similar to those found in general relativity. Major differences are observed
for negative values of the coupling parameter which results in a repulsive
gravitational component for high enough scalar field density distributions.
Adding self-interactions makes the degeneracy between $f(mathcal{R})$ and
general relativity even more pronounced, leaving very little room for
observational discrimination between the two theories.
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