{"title":"修正\\(\\boldsymbol{f(R,L_{m})}\\)重力与观测约束的精确宇宙学模型","authors":"Dinesh Chandra Maurya","doi":"10.1134/S020228932303012X","DOIUrl":null,"url":null,"abstract":"<p>This study is an investigation of exact cosmological models in modified <span>\\(f(R,L_{m})\\)</span> gravity with observational constraints, where <span>\\(R\\)</span> is the Ricci scalar, and <span>\\(L_{m}\\)</span> is the matter Lagrangian for a perfect fluid. We have obtained the field equations using a flat FLRW metric with matter Lagrangian <span>\\(L_{m}=-p\\)</span> and <span>\\(f(R,L_{m})=R/2+\\alpha L_{m}^{n}-\\beta\\)</span>, where <span>\\(\\alpha\\)</span>, <span>\\(\\beta\\)</span>, <span>\\(n\\)</span> are positive parameters. We have solved the field equations for the scale factor <span>\\(a(t)\\)</span> with the equation of state (EoS) <span>\\(p=\\omega\\rho\\)</span>, where <span>\\(p\\)</span> is the isotropic pressure and <span>\\(\\rho\\)</span> is the energy density. We have obtained the scale factor <span>\\(a(t)=k_{0}[\\sinh(k_{1}t+k_{2})]^{[2(n+\\omega-n\\omega]/[3n(1+\\omega)]}\\)</span>, where <span>\\(k_{1}=\\frac{\\sqrt{3\\beta}}{2}\\frac{n(1+\\omega)}{n+\\omega-n\\omega}\\)</span>, and <span>\\(k_{0}\\)</span>, <span>\\(k_{2}\\)</span> are integration constants. Using this scale factor, we have analyzed various cosmological parameters <span>\\(\\{H_{0},q_{0},j_{0},s_{0},t_{0}\\}\\)</span> with observational constraints by applying the <span>\\(\\chi^{2}\\)</span> test with four observational datasets <span>\\(H(z)\\)</span>, Union 2.1, JLA and Bined datasets. Also, we have analyzed the Om diagnostic parameter.</p>","PeriodicalId":583,"journal":{"name":"Gravitation and Cosmology","volume":"29 3","pages":"315 - 325"},"PeriodicalIF":1.2000,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Exact Cosmological Models in Modified \\\\(\\\\boldsymbol{f(R,L_{m})}\\\\) Gravity with Observational Constraints\",\"authors\":\"Dinesh Chandra Maurya\",\"doi\":\"10.1134/S020228932303012X\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>This study is an investigation of exact cosmological models in modified <span>\\\\(f(R,L_{m})\\\\)</span> gravity with observational constraints, where <span>\\\\(R\\\\)</span> is the Ricci scalar, and <span>\\\\(L_{m}\\\\)</span> is the matter Lagrangian for a perfect fluid. We have obtained the field equations using a flat FLRW metric with matter Lagrangian <span>\\\\(L_{m}=-p\\\\)</span> and <span>\\\\(f(R,L_{m})=R/2+\\\\alpha L_{m}^{n}-\\\\beta\\\\)</span>, where <span>\\\\(\\\\alpha\\\\)</span>, <span>\\\\(\\\\beta\\\\)</span>, <span>\\\\(n\\\\)</span> are positive parameters. We have solved the field equations for the scale factor <span>\\\\(a(t)\\\\)</span> with the equation of state (EoS) <span>\\\\(p=\\\\omega\\\\rho\\\\)</span>, where <span>\\\\(p\\\\)</span> is the isotropic pressure and <span>\\\\(\\\\rho\\\\)</span> is the energy density. We have obtained the scale factor <span>\\\\(a(t)=k_{0}[\\\\sinh(k_{1}t+k_{2})]^{[2(n+\\\\omega-n\\\\omega]/[3n(1+\\\\omega)]}\\\\)</span>, where <span>\\\\(k_{1}=\\\\frac{\\\\sqrt{3\\\\beta}}{2}\\\\frac{n(1+\\\\omega)}{n+\\\\omega-n\\\\omega}\\\\)</span>, and <span>\\\\(k_{0}\\\\)</span>, <span>\\\\(k_{2}\\\\)</span> are integration constants. Using this scale factor, we have analyzed various cosmological parameters <span>\\\\(\\\\{H_{0},q_{0},j_{0},s_{0},t_{0}\\\\}\\\\)</span> with observational constraints by applying the <span>\\\\(\\\\chi^{2}\\\\)</span> test with four observational datasets <span>\\\\(H(z)\\\\)</span>, Union 2.1, JLA and Bined datasets. Also, we have analyzed the Om diagnostic parameter.</p>\",\"PeriodicalId\":583,\"journal\":{\"name\":\"Gravitation and Cosmology\",\"volume\":\"29 3\",\"pages\":\"315 - 325\"},\"PeriodicalIF\":1.2000,\"publicationDate\":\"2023-09-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Gravitation and Cosmology\",\"FirstCategoryId\":\"4\",\"ListUrlMain\":\"https://link.springer.com/article/10.1134/S020228932303012X\",\"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}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Gravitation and Cosmology","FirstCategoryId":"4","ListUrlMain":"https://link.springer.com/article/10.1134/S020228932303012X","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}
Exact Cosmological Models in Modified \(\boldsymbol{f(R,L_{m})}\) Gravity with Observational Constraints
This study is an investigation of exact cosmological models in modified \(f(R,L_{m})\) gravity with observational constraints, where \(R\) is the Ricci scalar, and \(L_{m}\) is the matter Lagrangian for a perfect fluid. We have obtained the field equations using a flat FLRW metric with matter Lagrangian \(L_{m}=-p\) and \(f(R,L_{m})=R/2+\alpha L_{m}^{n}-\beta\), where \(\alpha\), \(\beta\), \(n\) are positive parameters. We have solved the field equations for the scale factor \(a(t)\) with the equation of state (EoS) \(p=\omega\rho\), where \(p\) is the isotropic pressure and \(\rho\) is the energy density. We have obtained the scale factor \(a(t)=k_{0}[\sinh(k_{1}t+k_{2})]^{[2(n+\omega-n\omega]/[3n(1+\omega)]}\), where \(k_{1}=\frac{\sqrt{3\beta}}{2}\frac{n(1+\omega)}{n+\omega-n\omega}\), and \(k_{0}\), \(k_{2}\) are integration constants. Using this scale factor, we have analyzed various cosmological parameters \(\{H_{0},q_{0},j_{0},s_{0},t_{0}\}\) with observational constraints by applying the \(\chi^{2}\) test with four observational datasets \(H(z)\), Union 2.1, JLA and Bined datasets. Also, we have analyzed the Om diagnostic parameter.
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