{"title":"Creation Field Cosmological Model with Variable Cosmological Term () in Bianchi Type III Space-Time","authors":"Raj Bali, Seema Saraf","doi":"10.1155/2024/5901224","DOIUrl":null,"url":null,"abstract":"The paper is devoted to the study of cosmological models with time-varying cosmological term (<span><svg height=\"8.68572pt\" style=\"vertical-align:-0.0498209pt\" version=\"1.1\" viewbox=\"-0.0498162 -8.6359 9.05107 8.68572\" width=\"9.05107pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"><use xlink:href=\"#g113-140\"></use></g></svg>)</span> in the presence of creation field in the framework of Bianchi type III space-time. To obtain deterministic model of the universe, we have assumed <span><svg height=\"13.7421pt\" style=\"vertical-align:-2.1507pt\" version=\"1.1\" viewbox=\"-0.0498162 -11.5914 23.294 13.7421\" width=\"23.294pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"><use xlink:href=\"#g113-140\"></use></g><g transform=\"matrix(.013,0,0,-0.013,12.543,0)\"></path></g></svg><span></span><svg height=\"13.7421pt\" style=\"vertical-align:-2.1507pt\" version=\"1.1\" viewbox=\"26.8761838 -11.5914 11.596 13.7421\" width=\"11.596pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,26.926,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,33.166,0)\"></path></g></svg><span></span><span><svg height=\"13.7421pt\" style=\"vertical-align:-2.1507pt\" version=\"1.1\" viewbox=\"38.4771838 -11.5914 13.347 13.7421\" width=\"13.347pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,38.527,0)\"></path></g><g transform=\"matrix(.0091,0,0,-0.0091,46.678,-5.741)\"></path></g></svg>,</span></span> where <svg height=\"8.8423pt\" style=\"vertical-align:-0.2064009pt\" version=\"1.1\" viewbox=\"-0.0498162 -8.6359 8.28119 8.8423\" width=\"8.28119pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"><use xlink:href=\"#g113-83\"></use></g></svg> is the scale factor, for steady state cosmology and creation field, and shear (<span><svg height=\"6.34998pt\" style=\"vertical-align:-0.2063899pt\" version=\"1.1\" viewbox=\"-0.0498162 -6.14359 7.47218 6.34998\" width=\"7.47218pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"></path></g></svg>)</span> is proportion to expansion (<span><svg height=\"9.49473pt\" style=\"vertical-align:-0.2063999pt\" version=\"1.1\" viewbox=\"-0.0498162 -9.28833 6.59789 9.49473\" width=\"6.59789pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"></path></g></svg>)</span> which leads to <span><svg height=\"10.1628pt\" style=\"vertical-align:-0.2064095pt\" version=\"1.1\" viewbox=\"-0.0498162 -9.95639 19.076 10.1628\" width=\"19.076pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,11.445,0)\"></path></g></svg><span></span><span><svg height=\"10.1628pt\" style=\"vertical-align:-0.2064095pt\" version=\"1.1\" viewbox=\"22.6581838 -9.95639 14.049 10.1628\" width=\"14.049pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,22.708,0)\"></path></g><g transform=\"matrix(.0091,0,0,-0.0091,31.392,-5.741)\"></path></g></svg>,</span></span> where <svg height=\"8.68572pt\" style=\"vertical-align:-0.0498209pt\" version=\"1.1\" viewbox=\"-0.0498162 -8.6359 7.94191 8.68572\" width=\"7.94191pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"><use xlink:href=\"#g113-67\"></use></g></svg> and <svg height=\"8.8423pt\" style=\"vertical-align:-0.2064009pt\" version=\"1.1\" viewbox=\"-0.0498162 -8.6359 8.8162 8.8423\" width=\"8.8162pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"><use xlink:href=\"#g113-68\"></use></g></svg> are the metric potentials to explain small anisotropic behaviour of the universe and its isotropy. To obtain the results in terms of cosmic time <span><svg height=\"8.02022pt\" style=\"vertical-align:-0.2063999pt\" version=\"1.1\" viewbox=\"-0.0498162 -7.81382 4.54925 8.02022\" width=\"4.54925pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"></path></g></svg>,</span> we have assumed <span><svg height=\"8.55521pt\" style=\"vertical-align:-0.2063904pt\" version=\"1.1\" viewbox=\"-0.0498162 -8.34882 17.789 8.55521\" width=\"17.789pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,10.158,0)\"><use xlink:href=\"#g117-34\"></use></g></svg><span></span><span><svg height=\"8.55521pt\" style=\"vertical-align:-0.2063904pt\" version=\"1.1\" viewbox=\"21.3711838 -8.34882 6.416 8.55521\" width=\"6.416pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,21.421,0)\"></path></g></svg>.</span></span> The model satisfies conservation equations, and creation field increases with time. The present model is free from singularity, has particle horizon, and provides a natural explanation for inflationary scenario and isotropization. Creation field and Einstein field equations are derived using principle of least action and Lagrangian formulation of variable cosmological term. For illustrative purposes, evolutionary behaviour of some cosmological parameters are shown graphically. The other physical aspects like accelerating behaviour of the model are also discussed. Thus, the model represents not only expanding universe but also accelerating which matches with the results of present-day observations.","PeriodicalId":7498,"journal":{"name":"Advances in High Energy Physics","volume":"63 1","pages":""},"PeriodicalIF":1.5000,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advances in High Energy Physics","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1155/2024/5901224","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, PARTICLES & FIELDS","Score":null,"Total":0}
引用次数: 0
Abstract
The paper is devoted to the study of cosmological models with time-varying cosmological term () in the presence of creation field in the framework of Bianchi type III space-time. To obtain deterministic model of the universe, we have assumed , where is the scale factor, for steady state cosmology and creation field, and shear () is proportion to expansion () which leads to , where and are the metric potentials to explain small anisotropic behaviour of the universe and its isotropy. To obtain the results in terms of cosmic time , we have assumed . The model satisfies conservation equations, and creation field increases with time. The present model is free from singularity, has particle horizon, and provides a natural explanation for inflationary scenario and isotropization. Creation field and Einstein field equations are derived using principle of least action and Lagrangian formulation of variable cosmological term. For illustrative purposes, evolutionary behaviour of some cosmological parameters are shown graphically. The other physical aspects like accelerating behaviour of the model are also discussed. Thus, the model represents not only expanding universe but also accelerating which matches with the results of present-day observations.
期刊介绍:
Advances in High Energy Physics publishes the results of theoretical and experimental research on the nature of, and interaction between, energy and matter. Considering both original research and focussed review articles, the journal welcomes submissions from small research groups and large consortia alike.