{"title":"The accelerated expansion in F(G,TμνTμν) gravity","authors":"Mihai Marciu, Dana Maria Ioan","doi":"10.1142/s0217732324500275","DOIUrl":null,"url":null,"abstract":"<p>In this paper, the basic Einstein–Hilbert cosmological model is extended by adding a new functional <span><math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"><mi>F</mi><mo stretchy=\"false\">(</mo><mi>G</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msub><msup><mrow><mi>T</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup><mo stretchy=\"false\">)</mo></math></span><span></span> in the fundamental action, encoding specific geometrical effects due to a nontrivial coupling with the Gauss–Bonnet invariant (<i>G</i>), and the energy–momentum squared term (<span><math altimg=\"eq-00004.gif\" display=\"inline\" overflow=\"scroll\"><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msub><msup><mrow><mi>T</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup></math></span><span></span>). After obtaining the corresponding gravitational field equations for the specific decomposition where <span><math altimg=\"eq-00005.gif\" display=\"inline\" overflow=\"scroll\"><mi>F</mi><mo stretchy=\"false\">(</mo><mi>G</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msub><msup><mrow><mi>T</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup><mo stretchy=\"false\">)</mo><mo>=</mo><mi>f</mi><mo stretchy=\"false\">(</mo><mi>G</mi><mo stretchy=\"false\">)</mo><mo>+</mo><mi>g</mi><mo stretchy=\"false\">(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msub><msup><mrow><mi>T</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup><mo stretchy=\"false\">)</mo></math></span><span></span>, we have explored the physical features of the cosmological model by considering the linear stability theory, an important analytical tool in the cosmological theory which can reveal the dynamical characteristics of the phase space. The analytical exploration of the corresponding phase space structure revealed that the present model can represent a viable dark energy model, with various stationary points where the effective equation of state corresponds to a de-Sitter epoch, possible explaining the early and late time acceleration of the Universe.</p>","PeriodicalId":18752,"journal":{"name":"Modern Physics Letters A","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Modern Physics Letters A","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1142/s0217732324500275","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}
引用次数: 0
Abstract
In this paper, the basic Einstein–Hilbert cosmological model is extended by adding a new functional in the fundamental action, encoding specific geometrical effects due to a nontrivial coupling with the Gauss–Bonnet invariant (G), and the energy–momentum squared term (). After obtaining the corresponding gravitational field equations for the specific decomposition where , we have explored the physical features of the cosmological model by considering the linear stability theory, an important analytical tool in the cosmological theory which can reveal the dynamical characteristics of the phase space. The analytical exploration of the corresponding phase space structure revealed that the present model can represent a viable dark energy model, with various stationary points where the effective equation of state corresponds to a de-Sitter epoch, possible explaining the early and late time acceleration of the Universe.
期刊介绍:
This letters journal, launched in 1986, consists of research papers covering current research developments in Gravitation, Cosmology, Astrophysics, Nuclear Physics, Particles and Fields, Accelerator physics, and Quantum Information. A Brief Review section has also been initiated with the purpose of publishing short reports on the latest experimental findings and urgent new theoretical developments.