{"title":"fQ引力中的偶极宇宙学","authors":"Andronikos Paliathanasis","doi":"10.1016/j.dark.2024.101585","DOIUrl":null,"url":null,"abstract":"<div><p>Symmetric teleparallel <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span>-gravity allows for the presence of a perfect fluid with a tilted velocity in the Kantowski–Sachs geometry. In this dipole model, we consider an ideal gas and we investigate the evolution of the physical parameters. The tilt parameter is constrained by the nonlinear function <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> through the non-diagonal equations of the field equations. We find that the dynamics always reduce to the vacuum solutions of STEGR. This includes the Kasner universe, when no cosmological term is introduced by the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> function, and the isotropic de Sitter universe, where <span><math><mrow><mi>f</mi><mfenced><mrow><mi>Q</mi></mrow></mfenced></mrow></math></span> plays the role of the cosmological constant. In the extreme tilt limit, the universe is consistently anisotropic and accelerated. However, the final solution matches that of STEGR.</p></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"46 ","pages":"Article 101585"},"PeriodicalIF":5.0000,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Dipole cosmology in fQ-gravity\",\"authors\":\"Andronikos Paliathanasis\",\"doi\":\"10.1016/j.dark.2024.101585\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Symmetric teleparallel <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span>-gravity allows for the presence of a perfect fluid with a tilted velocity in the Kantowski–Sachs geometry. In this dipole model, we consider an ideal gas and we investigate the evolution of the physical parameters. The tilt parameter is constrained by the nonlinear function <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> through the non-diagonal equations of the field equations. We find that the dynamics always reduce to the vacuum solutions of STEGR. This includes the Kasner universe, when no cosmological term is introduced by the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> function, and the isotropic de Sitter universe, where <span><math><mrow><mi>f</mi><mfenced><mrow><mi>Q</mi></mrow></mfenced></mrow></math></span> plays the role of the cosmological constant. In the extreme tilt limit, the universe is consistently anisotropic and accelerated. However, the final solution matches that of STEGR.</p></div>\",\"PeriodicalId\":48774,\"journal\":{\"name\":\"Physics of the Dark Universe\",\"volume\":\"46 \",\"pages\":\"Article 101585\"},\"PeriodicalIF\":5.0000,\"publicationDate\":\"2024-07-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physics of the Dark Universe\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2212686424001675\",\"RegionNum\":2,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physics of the Dark Universe","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2212686424001675","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
Symmetric teleparallel -gravity allows for the presence of a perfect fluid with a tilted velocity in the Kantowski–Sachs geometry. In this dipole model, we consider an ideal gas and we investigate the evolution of the physical parameters. The tilt parameter is constrained by the nonlinear function through the non-diagonal equations of the field equations. We find that the dynamics always reduce to the vacuum solutions of STEGR. This includes the Kasner universe, when no cosmological term is introduced by the function, and the isotropic de Sitter universe, where plays the role of the cosmological constant. In the extreme tilt limit, the universe is consistently anisotropic and accelerated. However, the final solution matches that of STEGR.
期刊介绍:
Physics of the Dark Universe is an innovative online-only journal that offers rapid publication of peer-reviewed, original research articles considered of high scientific impact.
The journal is focused on the understanding of Dark Matter, Dark Energy, Early Universe, gravitational waves and neutrinos, covering all theoretical, experimental and phenomenological aspects.