Comparison of perturbative and non-perturbative methods in f(R) gravity

AbstractIn this work, we investigate the structure and properties of neutron stars in $$R^2$$ R 2 gravity using two approaches, viz: the perturbative and non-perturbative methods. For this purpose, we consider NS with several nucleonic, as well as strange EoS generated in the framework of relativistic mean field models. The strange particles in the core of NS are in the form of $$\Lambda $$ Λ hyperons and quarks, in addition to the nucleons and leptons. In both the approaches, we obtain mass–radius relation for a wide range of values of the extra degree of freedom parameter a arising due to modification of gravity at large scales. The mass–radius relation of the chosen equation of states lies well within the observational limit in the case of GR. We identify the changes in the property of neutron star in the background of f(R) gravity, and compare the results in both the methods. We also identify the best suited method to study the modified gravity using the astrophysical observations.

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DYNAMICS OF DEEPLY BOUND ${\bar K}$ STATES

International Journal of Modern Physics A ◽

10.1142/s0217751x07036002 ◽

2007 ◽

Vol 22 (02n03) ◽

pp. 633-636 ◽

Cited By ~ 1

Author(s):

JIŘI MAREŠ ◽

ELIAHU FRIEDMAN ◽

AVRAHAM GAL

Keyword(s):

Binding Energy ◽

Mean Field ◽

Binding Energies ◽

Light Nuclei ◽

Nucleus Interaction ◽

Core Nucleus ◽

Relativistic Mean Field ◽

The Core ◽

Wide Range ◽

Rmf Model

Dynamical effects for [Formula: see text] deeply bound nuclear states are explored within a relativistic mean field (RMF) model. Varying the strength of [Formula: see text] - nucleus interaction, we cover a wide range of binding energies in order to evaluate the corresponding widths. A lower limit [Formula: see text] is placed on the width expected for binding energy in the range of [Formula: see text]. Substantial polarization of the core nucleus is found in light nuclei. We discuss the results of the FINUDA experiment at DAΦNE which presented evidence for deeply bound K- pp states in Li and 12 C .

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Critical properties of calibrated relativistic mean-field models for the transition to warm, nonhomogeneous nuclear and stellar matter

Physical Review C ◽

10.1103/physrevc.103.055804 ◽

2021 ◽

Vol 103 (5) ◽

Author(s):

Olfa Boukari ◽

Helena Pais ◽

Sofija Antić ◽

Constança Providência

Keyword(s):

Mean Field ◽

Critical Properties ◽

Stellar Matter ◽

Relativistic Mean Field ◽

Mean Field Models

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Parameter counting in relativistic mean-field models

Nuclear Physics A ◽

10.1016/s0375-9474(99)00839-8 ◽

2000 ◽

Vol 671 (1-4) ◽

pp. 447-460 ◽

Cited By ~ 68

Author(s):

R.J. Furnstahl ◽

Brian D. Serot

Keyword(s):

Mean Field ◽

Relativistic Mean Field ◽

Mean Field Models

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Dynamical Models for our Virgocentric Deviation from Hubble Flow

Highlights of Astronomy ◽

10.1017/s1539299600005979 ◽

1983 ◽

Vol 6 ◽

pp. 751-752

Author(s):

E. E. Salpeter

Keyword(s):

Mass Density ◽

Galaxy Cluster ◽

Virgo Cluster ◽

Point Of View ◽

Model Fit ◽

Cluster Center ◽

The Core ◽

Wide Range ◽

Range Of Values ◽

Hubble Flow

Spherically symmetric models for the dynamic development of a galaxy cluster from an initial overdensity have been carried out numerically, without dissipation or 2-body relaxation but with shell crossings included. The deviation ∆V from pure Hubble Flow of the Local Group, due to the retardation effect of the Virgo cluster and supercluster, has been calculated from a number of different models by Hoffman and Salpeter (Astrophys. J. 263, 1982, in press). The results are somewhat surprising if one takes the point of view of (a) insisting that the dynamic model fit the observed dispersion of galaxy systemic velocities in the core of the Virgo cluster, but (b) allowing the mass to light ratio M/L to be an arbitrary (but smoothly varying) function of distance from the Virgo cluster center. Point (a) essentially fixes the mass density and M/L in the core, but (b) still allows a wide range of values for the cosmological density parameters Ω (proportional to the average M/L far from the Virgo cluster). With this point of view ∆V actually decreases with increasing Ω: If M/L is constant, Ω ≈ 0.3 and ∆V ≈ 250 km s–1 (Hoffman, Olson and Salpeter, Ap. J. 242, 861, 1980); for Ω ~ 0.05, ∆V would exceed 350 km s–1; for Ω = 1, AV could be less than 150 km s–1.

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