{"title":"幂律宇宙学中 f(R,∇R)引力模型的观测约束","authors":"A. Dixit","doi":"10.1139/cjp-2023-0122","DOIUrl":null,"url":null,"abstract":"In this paper, we have considered the flat Friedmann-Lemaître-Robertson-Walker (FRW) model in the framework of f( R, ∇ R) gravity. We have analyzed the significance of bulk viscosity in the f( R, ∇ R) gravity model to study the expansion of the universe. We have considered two bulk viscosity parameterizations and the use of power-law cosmology to constrain the model parameters H0 and q. Using the Bayesian analysis and likelihood function in conjunction with the Markov Chain Monte Carlo method, we obtained the model parameters [Formula: see text] and [Formula: see text]. The behaviors of energy density, bulk viscous pressure, and the effective equation of the state parameter with redshift are investigated in detail. These features demonstrate that the bulk viscosity is a valid candidate for acquiring the negative pressure needed to effectively drive the expansion of the universe. To check the validity of the f( R, ∇ R) model, we also analyze the behavior of energy conditions. The adiabatic squared speed of the sound is used to test the model’s stability. The Om( z) diagnostic is used in the model to identify the quintessence and phantom regions.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":1.1000,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Observational constraint in f(R, ∇R) gravity model in power-law cosmology\",\"authors\":\"A. Dixit\",\"doi\":\"10.1139/cjp-2023-0122\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"In this paper, we have considered the flat Friedmann-Lemaître-Robertson-Walker (FRW) model in the framework of f( R, ∇ R) gravity. We have analyzed the significance of bulk viscosity in the f( R, ∇ R) gravity model to study the expansion of the universe. We have considered two bulk viscosity parameterizations and the use of power-law cosmology to constrain the model parameters H0 and q. Using the Bayesian analysis and likelihood function in conjunction with the Markov Chain Monte Carlo method, we obtained the model parameters [Formula: see text] and [Formula: see text]. The behaviors of energy density, bulk viscous pressure, and the effective equation of the state parameter with redshift are investigated in detail. These features demonstrate that the bulk viscosity is a valid candidate for acquiring the negative pressure needed to effectively drive the expansion of the universe. To check the validity of the f( R, ∇ R) model, we also analyze the behavior of energy conditions. The adiabatic squared speed of the sound is used to test the model’s stability. The Om( z) diagnostic is used in the model to identify the quintessence and phantom regions.\",\"PeriodicalId\":9413,\"journal\":{\"name\":\"Canadian Journal of Physics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.1000,\"publicationDate\":\"2024-01-15\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Canadian Journal of Physics\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1139/cjp-2023-0122\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Canadian Journal of Physics","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1139/cjp-2023-0122","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
Observational constraint in f(R, ∇R) gravity model in power-law cosmology
In this paper, we have considered the flat Friedmann-Lemaître-Robertson-Walker (FRW) model in the framework of f( R, ∇ R) gravity. We have analyzed the significance of bulk viscosity in the f( R, ∇ R) gravity model to study the expansion of the universe. We have considered two bulk viscosity parameterizations and the use of power-law cosmology to constrain the model parameters H0 and q. Using the Bayesian analysis and likelihood function in conjunction with the Markov Chain Monte Carlo method, we obtained the model parameters [Formula: see text] and [Formula: see text]. The behaviors of energy density, bulk viscous pressure, and the effective equation of the state parameter with redshift are investigated in detail. These features demonstrate that the bulk viscosity is a valid candidate for acquiring the negative pressure needed to effectively drive the expansion of the universe. To check the validity of the f( R, ∇ R) model, we also analyze the behavior of energy conditions. The adiabatic squared speed of the sound is used to test the model’s stability. The Om( z) diagnostic is used in the model to identify the quintessence and phantom regions.
期刊介绍:
The Canadian Journal of Physics publishes research articles, rapid communications, and review articles that report significant advances in research in physics, including atomic and molecular physics; condensed matter; elementary particles and fields; nuclear physics; gases, fluid dynamics, and plasmas; electromagnetism and optics; mathematical physics; interdisciplinary, classical, and applied physics; relativity and cosmology; physics education research; statistical mechanics and thermodynamics; quantum physics and quantum computing; gravitation and string theory; biophysics; aeronomy and space physics; and astrophysics.