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arXiv 1506.08055gr-qc
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Bianchi Ⅰ型宇宙中$f(R,T)$引力的标量场和时变宇宙学常数

Scalar field and time varying Cosmological constant in $f(R,T)$ gravity for Bianchi type-I Universe

G. P. Singh, Binaya K. Bishi, P. K. Sahoo

摘要:

本文分析了引力$f(R,T)$理论中标量场和宇宙学常数的行为。在这里,我们考虑了$f(R,T)$的最简单形式,即$f(R,T)=R+2f(T)$,其中$R$是里奇标量,$T$是能量动量张量的迹,并探索了空间均匀和各向异性的局部旋转对称(LRS)Bianchi I型宇宙学模型。假设宇宙中充满了两个不相互作用的物质源,即具有标量势的标量场(正常或幻影)和由于$f(R,T)$作用而产生的物质贡献。我们讨论了体积膨胀的幂律和指数律宇宙学模型,以及作为子模型的常数标量势和指数标量势。幂律模型与正常(精粹)和幻象标量场兼容,而指数体积膨胀模型仅与正常(精粹)标量场兼容。模型中的宇宙学常数值与观测结果一致。最后,我们讨论了这两种模型的一些物理和运动学性质。

英文摘要:

In this article, we have analysed the behaviour of scalar field and cosmological constant in $f(R,T)$ theory of gravity. Here, we have considered the simplest form of $f(R,T)$ i.e. $f(R,T)=R+2f(T)$, where $R$ is the Ricci scalar and $T$ is the trace of the energy momentum tensor and explored the spatially homogeneous and anisotropic Locally Rotationally Symmetric (LRS) Bianchi type-I cosmological model. It is assumed that the Universe is filled with two non-interacting matter sources namely scalar field (normal or phantom) with scalar potential and matter contribution due to $f(R,T)$ action. We have discussed two cosmological models according to power law and exponential law of the volume expansion along with constant and exponential scalar potential as sub models. Power law models are compatible with normal (quintessence) and phantom scalar field whereas exponential volume expansion models are compatible with only normal (quintessence) scalar field. The values of cosmological constant in our models are in agreement with the observational results. Finally, we have discussed some physical and kinematical properties of both the models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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