{"title":"非黎曼几何中的弹跳宇宙学分析","authors":"M. Sharif, M. Zeeshan Gul, Nusrat Fatima","doi":"10.1016/j.newast.2024.102211","DOIUrl":null,"url":null,"abstract":"<div><p>The main objective of this manuscript is to investigate the bouncing cosmology in the background of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> gravity, where <span><math><mi>Q</mi></math></span> defines the non-metricity. For this purpose, we use the reconstruction approach and consider a flat Friedmann–Robertson–Walker spacetime with perfect matter configuration. We examine how the first contracting phase gives the expansion by using a temporal derivative of the scale factor, i.e., <span><math><mrow><mover><mrow><mi>a</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo><</mo><mn>0</mn></mrow></math></span>, <span><math><mrow><mover><mrow><mi>a</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo>=</mo><mn>0</mn></mrow></math></span> and <span><math><mrow><mover><mrow><mi>a</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo>></mo><mn>0</mn></mrow></math></span> give contraction, bounce point and expansion phases, respectively. Further, we use the order reduction method to solve the modified field equations as these are very difficult due to the presence of additional non-linear expressions. It is analyzed that the original singularity of the universe diminishes for the required bounce conditions. We conclude that the acceleration occurs near the bouncing point and the considered <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> models are consistent with the current cosmic accelerated expansion.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"109 ","pages":"Article 102211"},"PeriodicalIF":1.9000,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Analysis of bouncing cosmology in non-Riemannian geometry\",\"authors\":\"M. Sharif, M. Zeeshan Gul, Nusrat Fatima\",\"doi\":\"10.1016/j.newast.2024.102211\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The main objective of this manuscript is to investigate the bouncing cosmology in the background of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> gravity, where <span><math><mi>Q</mi></math></span> defines the non-metricity. For this purpose, we use the reconstruction approach and consider a flat Friedmann–Robertson–Walker spacetime with perfect matter configuration. We examine how the first contracting phase gives the expansion by using a temporal derivative of the scale factor, i.e., <span><math><mrow><mover><mrow><mi>a</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo><</mo><mn>0</mn></mrow></math></span>, <span><math><mrow><mover><mrow><mi>a</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo>=</mo><mn>0</mn></mrow></math></span> and <span><math><mrow><mover><mrow><mi>a</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo>></mo><mn>0</mn></mrow></math></span> give contraction, bounce point and expansion phases, respectively. Further, we use the order reduction method to solve the modified field equations as these are very difficult due to the presence of additional non-linear expressions. It is analyzed that the original singularity of the universe diminishes for the required bounce conditions. We conclude that the acceleration occurs near the bouncing point and the considered <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> models are consistent with the current cosmic accelerated expansion.</p></div>\",\"PeriodicalId\":54727,\"journal\":{\"name\":\"New Astronomy\",\"volume\":\"109 \",\"pages\":\"Article 102211\"},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2024-02-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"New Astronomy\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1384107624000253\",\"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}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Astronomy","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1384107624000253","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}
Analysis of bouncing cosmology in non-Riemannian geometry
The main objective of this manuscript is to investigate the bouncing cosmology in the background of gravity, where defines the non-metricity. For this purpose, we use the reconstruction approach and consider a flat Friedmann–Robertson–Walker spacetime with perfect matter configuration. We examine how the first contracting phase gives the expansion by using a temporal derivative of the scale factor, i.e., , and give contraction, bounce point and expansion phases, respectively. Further, we use the order reduction method to solve the modified field equations as these are very difficult due to the presence of additional non-linear expressions. It is analyzed that the original singularity of the universe diminishes for the required bounce conditions. We conclude that the acceleration occurs near the bouncing point and the considered models are consistent with the current cosmic accelerated expansion.
期刊介绍:
New Astronomy publishes articles in all fields of astronomy and astrophysics, with a particular focus on computational astronomy: mathematical and astronomy techniques and methodology, simulations, modelling and numerical results and computational techniques in instrumentation.
New Astronomy includes full length research articles and review articles. The journal covers solar, stellar, galactic and extragalactic astronomy and astrophysics. It reports on original research in all wavelength bands, ranging from radio to gamma-ray.