{"title":"弦云与f(R,T)引力下的完美流体耦合的平面对称宇宙","authors":"R. G. Kandarkar, V. A. Thakare","doi":"10.1007/s10511-025-09874-1","DOIUrl":null,"url":null,"abstract":"<p>In this study, we considered plane-symmetric space-time in the presence of string clouds coupled with perfect fluid in<i> f</i> (<i>R</i>, <i>T</i>) theory of gravitation. Here, <i>R</i> is the Ricci scalar and <i>T</i> is the torsion scalar of space-time. The simple functional forms of the function <i>f</i> (<i>T</i>), such <i>f</i> (<i>R</i>, T) = <i>R +</i> 2<i>f</i> (<i>T</i>) is chosen for the investigation. Exact solutions of the field equations were obtained by considering the average scale factor. Different types of strings are discussed. Different forms of energy conditions are considered to obtain the exact solution of the nonlinear field equation. The following parameters were studied: i) average scale factor (<i>t</i><sup>2</sup> <i>+</i> λ/μ)<sup>1/2μ</sup> ii) shear scalar σ, iii) expansion scalar θ and iv) deceleration parameter <i>q</i>. Some of the physical and geometrical features of the model are represented using graphs.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"68 2","pages":"290 - 309"},"PeriodicalIF":0.7000,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Plane-Symmetric Universe in the Presence of String Clouds Coupled with the Perfect Fluid in f(R,T) Gravity\",\"authors\":\"R. G. Kandarkar, V. A. Thakare\",\"doi\":\"10.1007/s10511-025-09874-1\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>In this study, we considered plane-symmetric space-time in the presence of string clouds coupled with perfect fluid in<i> f</i> (<i>R</i>, <i>T</i>) theory of gravitation. Here, <i>R</i> is the Ricci scalar and <i>T</i> is the torsion scalar of space-time. The simple functional forms of the function <i>f</i> (<i>T</i>), such <i>f</i> (<i>R</i>, T) = <i>R +</i> 2<i>f</i> (<i>T</i>) is chosen for the investigation. Exact solutions of the field equations were obtained by considering the average scale factor. Different types of strings are discussed. Different forms of energy conditions are considered to obtain the exact solution of the nonlinear field equation. The following parameters were studied: i) average scale factor (<i>t</i><sup>2</sup> <i>+</i> λ/μ)<sup>1/2μ</sup> ii) shear scalar σ, iii) expansion scalar θ and iv) deceleration parameter <i>q</i>. Some of the physical and geometrical features of the model are represented using graphs.</p>\",\"PeriodicalId\":479,\"journal\":{\"name\":\"Astrophysics\",\"volume\":\"68 2\",\"pages\":\"290 - 309\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-08-28\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Astrophysics\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s10511-025-09874-1\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astrophysics","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1007/s10511-025-09874-1","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
Plane-Symmetric Universe in the Presence of String Clouds Coupled with the Perfect Fluid in f(R,T) Gravity
In this study, we considered plane-symmetric space-time in the presence of string clouds coupled with perfect fluid in f (R, T) theory of gravitation. Here, R is the Ricci scalar and T is the torsion scalar of space-time. The simple functional forms of the function f (T), such f (R, T) = R + 2f (T) is chosen for the investigation. Exact solutions of the field equations were obtained by considering the average scale factor. Different types of strings are discussed. Different forms of energy conditions are considered to obtain the exact solution of the nonlinear field equation. The following parameters were studied: i) average scale factor (t2+ λ/μ)1/2μ ii) shear scalar σ, iii) expansion scalar θ and iv) deceleration parameter q. Some of the physical and geometrical features of the model are represented using graphs.
期刊介绍:
Astrophysics (Ap) is a peer-reviewed scientific journal which publishes research in theoretical and observational astrophysics. Founded by V.A.Ambartsumian in 1965 Astrophysics is one of the international astronomy journals. The journal covers space astrophysics, stellar and galactic evolution, solar physics, stellar and planetary atmospheres, interstellar matter. Additional subjects include chemical composition and internal structure of stars, quasars and pulsars, developments in modern cosmology and radiative transfer.