Unimodular引力中的衔接条件

通过要求度规是引力场方程有效的分布解,在Unimodular引力下导出了当时空被一张非类光超曲面分割成两个区域时,度规所需满足的衔接条件.这些衔接条件可被用于塌缩星、可穿越虫洞或其他带壳物体的研究.与很多修改引力理论不同,本研究结果表明:Unimodular引力中非类光超曲面上的衔接条件与广义相对论中的完全相同,不变体积形式对其并没有额外的贡献.

Junction conditions in Unimodular gravity

For a non-null hypersurface separating the spacetime into two regions, we derive the junction conditions that the metric must be satisfied in Unimodular gravity by requiring the metric is a valid distributional solution to the field equations, which can be used to study collapsing stars, traversable wormholes or other objects with shells. In contrast to many modified theories of gravity, our results show that the junction conditions on a non-null hypersurface in Unimodular gravity are exactly the same as those in general relativity, and the invariant volume form seems to make no extra contributions to it.