{"title":"具有变量\\(\\boldsymbol{\\Lambda}\\)和\\(\\boldsymbol{G}\\)的各向异性Bianchi V型模型:宇宙学方面和奇点分析","authors":"S. Kotambkar, Prerna Parkhi, G. P. Singh","doi":"10.1134/S0202289325700227","DOIUrl":null,"url":null,"abstract":"<p>We consider an anisotropic space-time model and explore the universe evolution using analytical solutions of directional scale factors. In the Bianchi type V space-time framework, a new set of exact solutions of Einstein’s field equations with dynamical gravitational and cosmological constants have been obtained. The time-dependent expansion scalar is used to illustrate the observational compatibility with the Cosmic chronometer data. The cosmographic parameters are studied using the best-fit parameter values. The model yields a consistent evolution as compared to the <span>\\(\\Lambda\\)</span>–cold dark matter model at low redshift. Further, we study the existence of finite-time singularities in the anisotropic space-time. The universe evolution with the linear equation of state has been probed for different aspects, such as the behavior of physical parameters and dissipation of anisotropy. The model may explain the accelerating universe expansion with vanishing anisotropy at late times.</p>","PeriodicalId":583,"journal":{"name":"Gravitation and Cosmology","volume":"31 3","pages":"344 - 352"},"PeriodicalIF":1.0000,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Anisotropic Bianchi Type V Model with Variable \\\\(\\\\boldsymbol{\\\\Lambda}\\\\) and \\\\(\\\\boldsymbol{G}\\\\): Cosmological Aspects and Singularity Analysis\",\"authors\":\"S. Kotambkar, Prerna Parkhi, G. P. Singh\",\"doi\":\"10.1134/S0202289325700227\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We consider an anisotropic space-time model and explore the universe evolution using analytical solutions of directional scale factors. In the Bianchi type V space-time framework, a new set of exact solutions of Einstein’s field equations with dynamical gravitational and cosmological constants have been obtained. The time-dependent expansion scalar is used to illustrate the observational compatibility with the Cosmic chronometer data. The cosmographic parameters are studied using the best-fit parameter values. The model yields a consistent evolution as compared to the <span>\\\\(\\\\Lambda\\\\)</span>–cold dark matter model at low redshift. Further, we study the existence of finite-time singularities in the anisotropic space-time. The universe evolution with the linear equation of state has been probed for different aspects, such as the behavior of physical parameters and dissipation of anisotropy. The model may explain the accelerating universe expansion with vanishing anisotropy at late times.</p>\",\"PeriodicalId\":583,\"journal\":{\"name\":\"Gravitation and Cosmology\",\"volume\":\"31 3\",\"pages\":\"344 - 352\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2025-09-04\",\"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/S0202289325700227\",\"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/S0202289325700227","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}
Anisotropic Bianchi Type V Model with Variable \(\boldsymbol{\Lambda}\) and \(\boldsymbol{G}\): Cosmological Aspects and Singularity Analysis
We consider an anisotropic space-time model and explore the universe evolution using analytical solutions of directional scale factors. In the Bianchi type V space-time framework, a new set of exact solutions of Einstein’s field equations with dynamical gravitational and cosmological constants have been obtained. The time-dependent expansion scalar is used to illustrate the observational compatibility with the Cosmic chronometer data. The cosmographic parameters are studied using the best-fit parameter values. The model yields a consistent evolution as compared to the \(\Lambda\)–cold dark matter model at low redshift. Further, we study the existence of finite-time singularities in the anisotropic space-time. The universe evolution with the linear equation of state has been probed for different aspects, such as the behavior of physical parameters and dissipation of anisotropy. The model may explain the accelerating universe expansion with vanishing anisotropy at late times.
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