Nonperturbative models of quark stars in f(R) gravity
Quark star models with realistic equation of state in nonperturbative f(R) gravity are considered. The mass-radius relation for f(R)=R+αR2 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 cu...
Main Authors: | , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Elsevier
2015-03-01
|
Series: | Physics Letters B |
Online Access: | http://www.sciencedirect.com/science/article/pii/S0370269315000404 |
id |
doaj-8fe021ab24b84459869243dc4a18bc57 |
---|---|
record_format |
Article |
spelling |
doaj-8fe021ab24b84459869243dc4a18bc572020-11-25T00:03:59ZengElsevierPhysics Letters B0370-26932015-03-01742160166Nonperturbative models of quark stars in f(R) gravityArtyom V. Astashenok0Salvatore Capozziello1Sergei D. Odintsov2I. Kant Baltic Federal University, Institute of Physics and Technology, Nevskogo st. 14, 236041 Kaliningrad, RussiaDipartimento di Fisica, Università di Napoli “Federico II”, Italy; INFN Sez. di Napoli, Compl. Univ. di Monte S. Angelo, Ed. G., Via Cinthia, 9, I-80126 Napoli, Italy; Gran Sasso Science Institute (INFN), Viale F. Crispi, 7, I-67100 L'Aquila, Italy; Corresponding author.Instituciò Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain; Institut de Ciencies de l'Espai (IEEC-CSIC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra, Barcelona, SpainQuark star models with realistic equation of state in nonperturbative f(R) gravity are considered. The mass-radius relation for f(R)=R+αR2 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→0 for r→∞. In other 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 ϕ in this description. For distant observers, the gravitational mass of the star increases with increasing α (α>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 conformal 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. Keywords: Modified gravity, Compact stars, Quark starshttp://www.sciencedirect.com/science/article/pii/S0370269315000404 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Artyom V. Astashenok Salvatore Capozziello Sergei D. Odintsov |
spellingShingle |
Artyom V. Astashenok Salvatore Capozziello Sergei D. Odintsov Nonperturbative models of quark stars in f(R) gravity Physics Letters B |
author_facet |
Artyom V. Astashenok Salvatore Capozziello Sergei D. Odintsov |
author_sort |
Artyom V. Astashenok |
title |
Nonperturbative models of quark stars in f(R) gravity |
title_short |
Nonperturbative models of quark stars in f(R) gravity |
title_full |
Nonperturbative models of quark stars in f(R) gravity |
title_fullStr |
Nonperturbative models of quark stars in f(R) gravity |
title_full_unstemmed |
Nonperturbative models of quark stars in f(R) gravity |
title_sort |
nonperturbative models of quark stars in f(r) gravity |
publisher |
Elsevier |
series |
Physics Letters B |
issn |
0370-2693 |
publishDate |
2015-03-01 |
description |
Quark star models with realistic equation of state in nonperturbative f(R) gravity are considered. The mass-radius relation for f(R)=R+αR2 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→0 for r→∞. In other 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 ϕ in this description. For distant observers, the gravitational mass of the star increases with increasing α (α>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 conformal 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. Keywords: Modified gravity, Compact stars, Quark stars |
url |
http://www.sciencedirect.com/science/article/pii/S0370269315000404 |
work_keys_str_mv |
AT artyomvastashenok nonperturbativemodelsofquarkstarsinfrgravity AT salvatorecapozziello nonperturbativemodelsofquarkstarsinfrgravity AT sergeidodintsov nonperturbativemodelsofquarkstarsinfrgravity |
_version_ |
1725431607387488256 |