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- Title
Unimodular Approaches to the Cosmological Constant Problem.
- Authors
Jiroušek, Pavel
- Abstract
We review selected aspects of unimodular gravity and we discuss its viability as a solution of the old cosmological constant problem. In unimodular gravity, the cosmological constant is promoted to a global degree of freedom. We highlight the importance of correctly setting up its initial data in order to achieve a resolution of the cosmological constant problem on a semi-classical level. We review recent path integral analysis of quantum aspects of unimodular gravity to note that the semi-classical findings carry over to the quantum level as well. We point out that a resolution of the problem inherently relies on a global constraint on the spacetime four-volume. This makes the theory closely related to the vacuum energy sequester, which operates in a similar way. We discuss possible avenues of extending unimodular gravity that preserve the resolution of the cosmological constant problem.
- Subjects
COSMOLOGICAL constant; DEGREES of freedom; PATH integrals; QUANTUM wells; PATH analysis (Statistics)
- Publication
Universe (2218-1997), 2023, Vol 9, Issue 3, p131
- ISSN
2218-1997
- Publication type
Article
- DOI
10.3390/universe9030131