arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2004.12549gr-qcastro-ph.COhep-th
收藏

第二类最小修正引力理论

A theory of type-II minimally modified gravity

Antonio De Felice, Andreas Doll, Shinji Mukohyama

摘要:

我们提出了一个修正的引力理论,传播只有两个本地的引力自由度,并没有一个爱因斯坦框架。根据JCAP 01(2019)017 [arXiv:1810.01047 [gr-qc]]中的分类,这是一个II型最小修正引力理论。该理论的特征在于引力常量$G_{\rm N}$和一个非动力学辅助场$ϕ$的函数$V(ϕ)$,该辅助场扮演暗能量的角色。一旦我们确定了均匀和各向同性的宇宙学背景,$V(ϕ)$的形式就确定了,并且除了$G_{\rm N}$之外,该理论不再具有自由参数或自由函数。对于$V'(ϕ) = 0$,理论简化为广义相对论(GR),其中$G_N$是牛顿常数,$V=const.$是宇宙学常数。对于$V'(ϕ) \ne 0$,它表明,重力的行为不同,从GR,但GR与$G_{\rm N}$是牛顿常数恢复弱重力的距离和时间尺度足够短,比与$V(ϕ)$。因此,这个理论提供了宇宙学的最简单的框架,在这个框架中,对GR的偏离可以通过观测数据来检验。

英文摘要:

We propose a modified gravity theory that propagates only two local gravitational degrees of freedom and that does not have an Einstein frame. According to the classification in JCAP 01 (2019) 017 [arXiv:1810.01047 [gr-qc]], this is a type-II minimally modified gravity theory. The theory is characterized by the gravitational constant $G_{\rm N}$ and a function $V(ϕ)$ of a non-dynamical auxiliary field $ϕ$ that plays the role of dark energy. Once one fixes a homogeneous and isotropic cosmological background, the form of $V(ϕ)$ is determined and the theory no longer possesses a free parameter or a free function, besides $G_{\rm N}$. For $V'(ϕ) = 0$ the theory reduces to general relativity (GR) with $G_N$ being the Newton's constant and $V=const.$ being the cosmological constant. For $V'(ϕ) \ne 0$, it is shown that gravity behaves differently from GR but that GR with $G_{\rm N}$ being the Newton's constant is recovered for weak gravity at distance and time scales sufficiently shorter than the scale associated with $V(ϕ)$. Therefore this theory provides the simplest framework of cosmology in which deviations from GR can be tested by observational data.

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。

↑