{"title":"Cosmology of Metric-Affine \n \n \n R\n +\n β\n \n R\n 2\n \n \n $R + \\beta R^2$\n Gravity with Pure Shear Hypermomentum","authors":"Damianos Iosifidis, Ratbay Myrzakulov, Lucrezia Ravera","doi":"10.1002/prop.202300003","DOIUrl":null,"url":null,"abstract":"<p>In this paper, cosmological aspects of metric-affine <math>\n <semantics>\n <mrow>\n <mi>f</mi>\n <mo>(</mo>\n <mi>R</mi>\n <mo>)</mo>\n </mrow>\n <annotation>$f(R)$</annotation>\n </semantics></math> gravity with hyperfluid are studied. The equations of motion of the theory are obtained by varying the action with respect to the metric and the independent connection. Subsequently, considering a Friedmann-Lemaître-Robertson-Walker background, the modified Friedmann equations in the presence of a perfect cosmological hyperfluid is derived. Especially, a particular case in which <math>\n <semantics>\n <mrow>\n <mi>f</mi>\n <mrow>\n <mo>(</mo>\n <mi>R</mi>\n <mo>)</mo>\n </mrow>\n <mo>=</mo>\n <mi>R</mi>\n <mo>+</mo>\n <mi>β</mi>\n <msup>\n <mi>R</mi>\n <mn>2</mn>\n </msup>\n </mrow>\n <annotation>$f(R)=R+\\beta R^2$</annotation>\n </semantics></math> is focused, considering purely shear hypermomentum and finding exact solutions in the weak coupling limit.</p>","PeriodicalId":55150,"journal":{"name":"Fortschritte Der Physik-Progress of Physics","volume":"72 1","pages":""},"PeriodicalIF":5.6000,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/prop.202300003","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Fortschritte Der Physik-Progress of Physics","FirstCategoryId":"101","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/prop.202300003","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
In this paper, cosmological aspects of metric-affine gravity with hyperfluid are studied. The equations of motion of the theory are obtained by varying the action with respect to the metric and the independent connection. Subsequently, considering a Friedmann-Lemaître-Robertson-Walker background, the modified Friedmann equations in the presence of a perfect cosmological hyperfluid is derived. Especially, a particular case in which is focused, considering purely shear hypermomentum and finding exact solutions in the weak coupling limit.
本文研究了具有超流体的公因子 f ( R ) $f(R)$引力的宇宙学问题。通过改变关于度量和独立连接的作用,得到了理论的运动方程。随后,考虑弗里德曼-勒梅特尔-罗伯逊-沃克背景,导出了存在完美宇宙学超流体的修正弗里德曼方程。特别是关注了 f ( R ) = R + β R 2 $f(R)=R+\beta R^2$ 的特殊情况,考虑了纯剪切超动量并找到了弱耦合极限下的精确解。
期刊介绍:
The journal Fortschritte der Physik - Progress of Physics is a pure online Journal (since 2013).
Fortschritte der Physik - Progress of Physics is devoted to the theoretical and experimental studies of fundamental constituents of matter and their interactions e. g. elementary particle physics, classical and quantum field theory, the theory of gravitation and cosmology, quantum information, thermodynamics and statistics, laser physics and nonlinear dynamics, including chaos and quantum chaos. Generally the papers are review articles with a detailed survey on relevant publications, but original papers of general interest are also published.