{"title":"具有对数标量场的布兰斯-迪克理论中的广义幽灵暗能量模型","authors":"Pinki, Pankaj Kumar, C. P. Singh","doi":"10.1142/s0217732324500469","DOIUrl":null,"url":null,"abstract":"<p>We study generalized ghost dark energy model in Brans–Dicke theory within the framework of flat Friedmann–Lemaitre–Robertson–Walker Universe. We assume the well-motivated logarithmic form of Brans–Dicke scalar field in terms of the scale factor to find the observational parameters such as equation of state parameter <span><math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"><msub><mrow><mi>w</mi></mrow><mrow><mi>g</mi></mrow></msub></math></span><span></span> and deceleration parameter <i>q</i>. It is observed that the equation of state parameter crosses the phantom divide line <span><math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"><mo stretchy=\"false\">(</mo><msub><mrow><mi>w</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>=</mo><mo>−</mo><mn>1</mn><mo stretchy=\"false\">)</mo></math></span><span></span> for a suitable range of model parameters. We observe that the deceleration parameter is time-dependent which shows the recent phase transition from decelerated to accelerated expansion of the Universe. Moreover, the model shows that the Universe will go through two future phase transitions, recent accelerated expansion to decelerated expansion and again decelerated expansion to accelerated expansion. We have also plotted the trajectories of the model in the <span><math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"><msub><mrow><mi>w</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>−</mo><msubsup><mrow><mi>w</mi></mrow><mrow><mi>g</mi></mrow><mrow><mi>′</mi></mrow></msubsup></math></span><span></span> plane for different values of parameters and explored the freezing and thawing regions. Further, we apply the sound squared speed method to check the stability of the model and found that the model is stable for suitable range of parameters.</p>","PeriodicalId":18752,"journal":{"name":"Modern Physics Letters A","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Generalized ghost dark energy model in Brans–Dicke theory with logarithmic scalar field\",\"authors\":\"Pinki, Pankaj Kumar, C. P. Singh\",\"doi\":\"10.1142/s0217732324500469\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We study generalized ghost dark energy model in Brans–Dicke theory within the framework of flat Friedmann–Lemaitre–Robertson–Walker Universe. We assume the well-motivated logarithmic form of Brans–Dicke scalar field in terms of the scale factor to find the observational parameters such as equation of state parameter <span><math altimg=\\\"eq-00001.gif\\\" display=\\\"inline\\\" overflow=\\\"scroll\\\"><msub><mrow><mi>w</mi></mrow><mrow><mi>g</mi></mrow></msub></math></span><span></span> and deceleration parameter <i>q</i>. It is observed that the equation of state parameter crosses the phantom divide line <span><math altimg=\\\"eq-00002.gif\\\" display=\\\"inline\\\" overflow=\\\"scroll\\\"><mo stretchy=\\\"false\\\">(</mo><msub><mrow><mi>w</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>=</mo><mo>−</mo><mn>1</mn><mo stretchy=\\\"false\\\">)</mo></math></span><span></span> for a suitable range of model parameters. We observe that the deceleration parameter is time-dependent which shows the recent phase transition from decelerated to accelerated expansion of the Universe. Moreover, the model shows that the Universe will go through two future phase transitions, recent accelerated expansion to decelerated expansion and again decelerated expansion to accelerated expansion. We have also plotted the trajectories of the model in the <span><math altimg=\\\"eq-00003.gif\\\" display=\\\"inline\\\" overflow=\\\"scroll\\\"><msub><mrow><mi>w</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>−</mo><msubsup><mrow><mi>w</mi></mrow><mrow><mi>g</mi></mrow><mrow><mi>′</mi></mrow></msubsup></math></span><span></span> plane for different values of parameters and explored the freezing and thawing regions. Further, we apply the sound squared speed method to check the stability of the model and found that the model is stable for suitable range of parameters.</p>\",\"PeriodicalId\":18752,\"journal\":{\"name\":\"Modern Physics Letters A\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.5000,\"publicationDate\":\"2024-04-26\",\"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/s0217732324500469\",\"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}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Modern Physics Letters A","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1142/s0217732324500469","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}
Generalized ghost dark energy model in Brans–Dicke theory with logarithmic scalar field
We study generalized ghost dark energy model in Brans–Dicke theory within the framework of flat Friedmann–Lemaitre–Robertson–Walker Universe. We assume the well-motivated logarithmic form of Brans–Dicke scalar field in terms of the scale factor to find the observational parameters such as equation of state parameter and deceleration parameter q. It is observed that the equation of state parameter crosses the phantom divide line for a suitable range of model parameters. We observe that the deceleration parameter is time-dependent which shows the recent phase transition from decelerated to accelerated expansion of the Universe. Moreover, the model shows that the Universe will go through two future phase transitions, recent accelerated expansion to decelerated expansion and again decelerated expansion to accelerated expansion. We have also plotted the trajectories of the model in the plane for different values of parameters and explored the freezing and thawing regions. Further, we apply the sound squared speed method to check the stability of the model and found that the model is stable for suitable range of parameters.
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.