{"title":"Phantom Dark Energy Nature of String-Fluid Cosmological Models in \\(\\boldsymbol{f(Q)}\\)-Gravity","authors":"Dinesh Chandra Maurya","doi":"10.1134/S0202289323040151","DOIUrl":null,"url":null,"abstract":"<p>The present investigation is focused on a curvatureless and torsionless modified nonmetricity theory of gravity in the context of string fluid. For that, we use an anisotropic, locally rotationally symmetric (LRS), Bianchi Type I space-time universe with the arbitrary function <span>\\(f(Q)=Q+\\Lambda\\)</span>, where <span>\\(Q\\)</span> is the nonmetricity scalar and <span>\\(\\Lambda\\)</span> is the cosmological constant. We solve the field equations using a time-dependent deceleration parameter and obtain various cosmological parameters. To obtain the best-fit values of the model parameters, we use the observational constraints on Hubble function <span>\\(H(z)\\)</span> and the apparent magnitude <span>\\(m(z)\\)</span> using the observational datasets <span>\\(H(z)\\)</span> and SNe Ia. Using these values of model parameters, we investigate cosmological scenarios of the model. We observe the behavior of the variable dark energy equation of state (EoS) parameter <span>\\(\\omega\\)</span> in the context of a string fluid universe and find the present value of the effective EoS parameter <span>\\(\\omega^{\\textrm{eff}}<-1\\)</span> that corresponds to phantom dark energy. Also, we analyze the statefinder parameters and estimate the present age of the universe.</p>","PeriodicalId":583,"journal":{"name":"Gravitation and Cosmology","volume":"29 4","pages":"345 - 361"},"PeriodicalIF":1.2000,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Gravitation and Cosmology","FirstCategoryId":"4","ListUrlMain":"https://link.springer.com/article/10.1134/S0202289323040151","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
The present investigation is focused on a curvatureless and torsionless modified nonmetricity theory of gravity in the context of string fluid. For that, we use an anisotropic, locally rotationally symmetric (LRS), Bianchi Type I space-time universe with the arbitrary function \(f(Q)=Q+\Lambda\), where \(Q\) is the nonmetricity scalar and \(\Lambda\) is the cosmological constant. We solve the field equations using a time-dependent deceleration parameter and obtain various cosmological parameters. To obtain the best-fit values of the model parameters, we use the observational constraints on Hubble function \(H(z)\) and the apparent magnitude \(m(z)\) using the observational datasets \(H(z)\) and SNe Ia. Using these values of model parameters, we investigate cosmological scenarios of the model. We observe the behavior of the variable dark energy equation of state (EoS) parameter \(\omega\) in the context of a string fluid universe and find the present value of the effective EoS parameter \(\omega^{\textrm{eff}}<-1\) that corresponds to phantom dark energy. Also, we analyze the statefinder parameters and estimate the present age of the universe.
期刊介绍:
Gravitation and Cosmology is a peer-reviewed periodical, dealing with the full range of topics of gravitational physics and relativistic cosmology and published under the auspices of the Russian Gravitation Society and Peoples’ Friendship University of Russia. The journal publishes research papers, review articles and brief communications on the following fields: theoretical (classical and quantum) gravitation; relativistic astrophysics and cosmology, exact solutions and modern mathematical methods in gravitation and cosmology, including Lie groups, geometry and topology; unification theories including gravitation; fundamental physical constants and their possible variations; fundamental gravity experiments on Earth and in space; related topics. It also publishes selected old papers which have not lost their topicality but were previously published only in Russian and were not available to the worldwide research community