Nonperturbative models of quark stars in $f(R)$ gravity

Abstract

Quark star models with realistic equation of state in nonperturbative $f(R)$ gravity are considered. The mass-radius relation for $f(R)=R+\alpha R^2$ model is obtained. Considering scalar curvature $R$ as an independent function, one can find out, for each value of central density, the unique value of central curvature for which one has solutions with the required asymptotic $R\to 0$ for $r\to \infty$. In another words, one needs a fine-tuning for $R$ to achieve quark stars in $f(R)$ gravity. We consider also the analogue description in corresponding scalar-tensor gravity. The fine-tuning on $R$ is equivalent to the fine-tuning on the scalar field $\varphi$ in this description. For distant observers, the gravitational mass of the star increases with increasing $\alpha$ ($\alpha >0$) but the interpretation of this fact depends on frame where we work. Considering directly $f(R)$ gravity, one can say that increasing of mass occurs by the "gravitational sphere" outside the star with some "effective mass". On the other hand, in scalar-tensor theory, we also have a dilaton sphere (or "disphere") outside the star but its contribution to gravitational mass for distant observer is negligible. We show that it is possible to discriminate modified theories of gravity from General Relativity due to the gravitational redshift of the thermal spectrum emerging from the surface of the star.

9 pages, 5 figures, accepted for publication in Phys. Lett. B

References in corpus (14)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• Palatini Approach to Modified Gravity: f(R) Theories and Beyond
• Future of the universe in modified gravitational theories: Approaching to the finite-time future singularity
• Hydrostatic equilibrium and stellar structure in f(R)-gravity
• Phantom scalar dark energy as modified gravity: understanding the origin of the Big Rip singularity
• Extreme neutron stars from Extended Theories of Gravity
• Relativistic stars in f(R) gravity, and absence thereof
• Collapsing spherical stars in f(R) gravity
• Time-dependent matter instability and star singularity in $F(R)$ gravity
• The existence of relativistic stars in f(R) gravity
• On the 1/c Expansion of f(R) Gravity
• Tracking quintessence by cosmic shear - Constraints from VIRMOS-Descart and CFHTLS and future prospects
• Withholding Potentials, Absence of Ghosts and Relationship between Minimal Dilatonic Gravity and f(R) Theories

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