{"title":"Probing Weyl-type f(Q,T) gravity: Cosmological implications and constraints","authors":"A.H.A. Alfedeel , M. Koussour , N. Myrzakulov","doi":"10.1016/j.ascom.2024.100821","DOIUrl":null,"url":null,"abstract":"<div><p>In this paper, we investigate the cosmological implications and constraints of Weyl-type <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity. This theory introduces a coupling between the non-metricity <span><math><mi>Q</mi></math></span> and the trace <span><math><mi>T</mi></math></span> of the energy–momentum tensor, using the principles of proper Weyl geometry. In this geometry, the scalar non-metricity <span><math><mi>Q</mi></math></span>, which characterizes the deviations from Riemannian geometry, is expressed in its standard Weyl form <span><math><mrow><msub><mrow><mo>∇</mo></mrow><mrow><mi>μ</mi></mrow></msub><msub><mrow><mi>g</mi></mrow><mrow><mi>α</mi><mi>β</mi></mrow></msub><mo>=</mo><mo>−</mo><msub><mrow><mi>w</mi></mrow><mrow><mi>μ</mi></mrow></msub><msub><mrow><mi>g</mi></mrow><mrow><mi>α</mi><mi>β</mi></mrow></msub></mrow></math></span> and is determined by a vector field <span><math><msub><mrow><mi>w</mi></mrow><mrow><mi>μ</mi></mrow></msub></math></span>. To study the implications of this theory, we propose a deceleration parameter with a single unknown parameter <span><math><mi>χ</mi></math></span>, which we constrain by using the latest cosmological data. By solving the field equations derived from Weyl-type <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity, we aim to understand the behavior of the energy conditions within this framework. In the present work, we consider two well-motivated forms of the function <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>: (i) the linear model represented by <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mi>α</mi><mi>Q</mi><mo>+</mo><mfrac><mrow><mi>β</mi></mrow><mrow><mn>6</mn><msup><mrow><mi>κ</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac><mi>T</mi></mrow></math></span>, and (ii) the coupling model represented by <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mfrac><mrow><mi>γ</mi></mrow><mrow><mn>6</mn><msubsup><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow><mrow><mn>2</mn></mrow></msubsup><msup><mrow><mi>κ</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac><mi>Q</mi><mi>T</mi></mrow></math></span>, where <span><math><mi>α</mi></math></span>, <span><math><mi>β</mi></math></span>, and <span><math><mi>γ</mi></math></span> are free parameters. Here, <span><math><mrow><msup><mrow><mi>κ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>16</mn><mi>π</mi><mi>G</mi></mrow></mfrac></mrow></math></span> represents the gravitational coupling constant. In both of the models considered, the strong energy condition is violated, indicating consistency with the present accelerated expansion. However, the null, weak, and dominant energy conditions are satisfied in these models.</p></div>","PeriodicalId":48757,"journal":{"name":"Astronomy and Computing","volume":"47 ","pages":"Article 100821"},"PeriodicalIF":1.9000,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astronomy and Computing","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2213133724000362","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
In this paper, we investigate the cosmological implications and constraints of Weyl-type gravity. This theory introduces a coupling between the non-metricity and the trace of the energy–momentum tensor, using the principles of proper Weyl geometry. In this geometry, the scalar non-metricity , which characterizes the deviations from Riemannian geometry, is expressed in its standard Weyl form and is determined by a vector field . To study the implications of this theory, we propose a deceleration parameter with a single unknown parameter , which we constrain by using the latest cosmological data. By solving the field equations derived from Weyl-type gravity, we aim to understand the behavior of the energy conditions within this framework. In the present work, we consider two well-motivated forms of the function : (i) the linear model represented by , and (ii) the coupling model represented by , where , , and are free parameters. Here, represents the gravitational coupling constant. In both of the models considered, the strong energy condition is violated, indicating consistency with the present accelerated expansion. However, the null, weak, and dominant energy conditions are satisfied in these models.
Astronomy and ComputingASTRONOMY & ASTROPHYSICSCOMPUTER SCIENCE,-COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS
CiteScore
4.10
自引率
8.00%
发文量
67
期刊介绍:
Astronomy and Computing is a peer-reviewed journal that focuses on the broad area between astronomy, computer science and information technology. The journal aims to publish the work of scientists and (software) engineers in all aspects of astronomical computing, including the collection, analysis, reduction, visualisation, preservation and dissemination of data, and the development of astronomical software and simulations. The journal covers applications for academic computer science techniques to astronomy, as well as novel applications of information technologies within astronomy.