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arXiv 2402.00141gr-qc
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作为初值问题的幺模引力

Unimodular gravity as an initial value problem

J. E. Herrera, Y. Bonder

AI总结:

本文用 Dirac 算法分析真空幺模引力的约束,证明其初值问题适定,并给出物质作用量保持适定性的充分条件。

摘要:

幺模引力是一种引人关注的修改引力理论,为宇宙学常数问题提供了自然的解决方案。然而,要使幺模引力被视为一种可行的引力理论,必须证明它具有适定的初值表述。在真空情形下,我们应用 Dirac 算法找出该理论的全部约束。随后证明,对于满足这些约束的初始数据,其演化是适定的。最后,我们给出了物质作用量保持幺模引力初值问题适定性的充分条件。作为推论,我们论证了对时空体积元的“幺模”限制可以通过适当选择时移函数来满足。

英文摘要:

Unimodular gravity is a compelling modified theory of gravity that offers a natural solution to the cosmological constant problem. However, for unimodular gravity to be considered a viable theory of gravity, one has to show that it has a well-posed initial value formulation. Working in vacuum, we apply Dirac's algorithm to find all the constraints of the theory. Then we prove that, for initial data compatible with these constraints, the evolution is well posed. Finally, we find sufficient conditions for a matter action to preserve the well-posedness of the initial value problem of unimodular gravity. As a corollary, we argue that the "unimodular" restriction on the spacetime volume element can be satisfied by a suitable choice of the lapse function.

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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