Neutron stars phenomenology with scalar–tensor inflationary attractors

In this work we shall study the implications of a subclass of E-models cosmological attractors, namely of a-attractors, on hydrodynamically stable slowly rotating neutron stars. Specifically, we shall present the Jordan frame theory of the a-attractors, and by using a conformal transformation we sha...

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Autores: Odintsov, Sergei D., Oikonomou, Vasilis K.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2021
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/249633
Acceso en línea:http://hdl.handle.net/10261/249633
Access Level:acceso abierto
Palabra clave:Neutron stars
Scalar-tension theories
Alpha attractors
Inflationary attractos
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spelling Neutron stars phenomenology with scalar–tensor inflationary attractorsOdintsov, Sergei D.Oikonomou, Vasilis K.Neutron starsScalar-tension theoriesAlpha attractorsInflationary attractosIn this work we shall study the implications of a subclass of E-models cosmological attractors, namely of a-attractors, on hydrodynamically stable slowly rotating neutron stars. Specifically, we shall present the Jordan frame theory of the a-attractors, and by using a conformal transformation we shall derive the Einstein frame theory. We discuss the inflationary context of a-attractors in order to specify the allowed range of values for the free parameters of the model based on the latest cosmic-microwave-background-based Planck 2018 data. Accordingly, using the notation and physical units frequently used in theoretical astrophysics contexts, we shall derive the Tolman–Oppenheimer–Volkoff equations in the Einstein frame. Assuming a piecewise polytropic equation of state, the lowest density part of which shall be chosen to be the WFF1, or APR or the SLy EoS, we numerically solve the Tolman–Oppenheimer–Volkoff equations using a double shooting python-based “LSODA” numerical code. The resulting picture depends on the value of the parameter a characterizing the a-attractors. As we show, for large values of a, which do not produce a viable inflationary era, the M–R graphs are nearly identical to the general relativistic result, and these two are discriminated at large central densities values. Also, for large a-values, the WFF1 equation of state is excluded, due to the GW170817 constraints on the radius of an M∼1.6M neutron star, which must be larger than R=10.68km and on the radius corresponding to the maximum mass which must be larger than R=9.6km. In addition, the small a cases produce larger masses and radii compared to the general relativistic case and are compatible with the GW170817 constraints on the radii of neutron stars. A notable feature is that as the parameter a decreases, the radii of the static hydrodynamically stable neutron stars increase. Our results indicate deep and not yet completely understood connections between non-minimal inflationary attractors and neutron stars phenomenology in scalar–tensor theory.V.K. Oikonomou is indebted to N. Stergioulas and his M.Sc. student Vaggelis Smyrniotis for the many hours spend on neutron star physics discussions and for sharing his professional knowledge on numerical integration of neutron stars in python. The work by SDO is supported by the Russian Foundation for Basic Research (Grant N. 20-52-05009).Peer reviewedElsevierRussian Foundation for Basic ResearchConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2021202120212021info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/249633reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://doi.org/10.1016/j.dark.2021.100805Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2496332026-05-22T06:33:51Z
dc.title.none.fl_str_mv Neutron stars phenomenology with scalar–tensor inflationary attractors
title Neutron stars phenomenology with scalar–tensor inflationary attractors
spellingShingle Neutron stars phenomenology with scalar–tensor inflationary attractors
Odintsov, Sergei D.
Neutron stars
Scalar-tension theories
Alpha attractors
Inflationary attractos
title_short Neutron stars phenomenology with scalar–tensor inflationary attractors
title_full Neutron stars phenomenology with scalar–tensor inflationary attractors
title_fullStr Neutron stars phenomenology with scalar–tensor inflationary attractors
title_full_unstemmed Neutron stars phenomenology with scalar–tensor inflationary attractors
title_sort Neutron stars phenomenology with scalar–tensor inflationary attractors
dc.creator.none.fl_str_mv Odintsov, Sergei D.
Oikonomou, Vasilis K.
author Odintsov, Sergei D.
author_facet Odintsov, Sergei D.
Oikonomou, Vasilis K.
author_role author
author2 Oikonomou, Vasilis K.
author2_role author
dc.contributor.none.fl_str_mv Russian Foundation for Basic Research
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Neutron stars
Scalar-tension theories
Alpha attractors
Inflationary attractos
topic Neutron stars
Scalar-tension theories
Alpha attractors
Inflationary attractos
description In this work we shall study the implications of a subclass of E-models cosmological attractors, namely of a-attractors, on hydrodynamically stable slowly rotating neutron stars. Specifically, we shall present the Jordan frame theory of the a-attractors, and by using a conformal transformation we shall derive the Einstein frame theory. We discuss the inflationary context of a-attractors in order to specify the allowed range of values for the free parameters of the model based on the latest cosmic-microwave-background-based Planck 2018 data. Accordingly, using the notation and physical units frequently used in theoretical astrophysics contexts, we shall derive the Tolman–Oppenheimer–Volkoff equations in the Einstein frame. Assuming a piecewise polytropic equation of state, the lowest density part of which shall be chosen to be the WFF1, or APR or the SLy EoS, we numerically solve the Tolman–Oppenheimer–Volkoff equations using a double shooting python-based “LSODA” numerical code. The resulting picture depends on the value of the parameter a characterizing the a-attractors. As we show, for large values of a, which do not produce a viable inflationary era, the M–R graphs are nearly identical to the general relativistic result, and these two are discriminated at large central densities values. Also, for large a-values, the WFF1 equation of state is excluded, due to the GW170817 constraints on the radius of an M∼1.6M neutron star, which must be larger than R=10.68km and on the radius corresponding to the maximum mass which must be larger than R=9.6km. In addition, the small a cases produce larger masses and radii compared to the general relativistic case and are compatible with the GW170817 constraints on the radii of neutron stars. A notable feature is that as the parameter a decreases, the radii of the static hydrodynamically stable neutron stars increase. Our results indicate deep and not yet completely understood connections between non-minimal inflationary attractors and neutron stars phenomenology in scalar–tensor theory.
publishDate 2021
dc.date.none.fl_str_mv 2021
2021
2021
2021
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Postprint
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/249633
url http://hdl.handle.net/10261/249633
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://doi.org/10.1016/j.dark.2021.100805
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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