How unimodular gravity theories differ from general relativity at quantum level
How unimodular gravity theories differ from general relativity at quantum level
复制标题
单位模引力理论与量子层面的广义相对论有何不同
DOI：
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
A. Tureanu
中科院分区：
文献类型：
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作者：
R. Bufalo;R. Bufalo;M. Oksanen;A. Tureanu
我们研究了两种单模引力的路径积分量子化。首先分析了一个完全同态不变的理论，它不包括度量上的幺模条件，同时仍然等价于经典水平上的其他幺模引力理论。路径积分的形式与广义相对论（GR）中的形式相同，只是宇宙学常数是一个未指定的变量值，因此它与任何耦合常数无关。当宇宙的状态是真空态的叠加时，路径积分被扩展到包括对宇宙常数的积分。其次，我们分析了标准的么模引力理论，其中度量行列式是固定的约束。它的路径积分与GR的路径积分有两个不同之处：时空的度规仅在空间平均上满足么模条件，而哈密顿约束和相关的规范条件在空间平均上都为零。最后，建立了所给引力幺模理论之间的正则关系。
We investigate path integral quantization of two versions of unimodular gravity. First a fully diffeomorphism-invariant theory is analyzed, which does not include a unimodular condition on the metric, while still being equivalent to other unimodular gravity theories at the classical level. The path integral has the same form as in general relativity (GR), except that the cosmological constant is an unspecified value of a variable, and it thus is unrelated to any coupling constant. When the state of the universe is a superposition of vacuum states, the path integral is extended to include an integral over the cosmological constant. Second, we analyze the standard unimodular theory of gravity, where the metric determinant is fixed by a constraint. Its path integral differs from the one of GR in two ways: the metric of spacetime satisfies the unimodular condition only in average over space, and both the Hamiltonian constraint and the associated gauge condition have zero average over space. Finally, the canonical relation between the given unimodular theories of gravity is established.
DOI：
10.1088/1475-7516/2014/06/017
发表时间：
2014-06-01
影响因子：
6.4
作者：
Chamseddine, Ali H.;Mukhanov, Viatcheslav;Vikman, Alexander
通讯作者：
Vikman, Alexander