1. A possible origin of the $\alpha$-vacuum as the initial state of the Universe
- Author
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Chen, Pisin, Lin, Kuan-Nan, Lin, Wei-Chen, and Yeom, Dong-han
- Subjects
General Relativity and Quantum Cosmology - Abstract
We investigate the cosmological observables using the Euclidean path integral approach. Specifically, we study both the no-boundary compact instantons scenario and the Euclidean wormholes scenario that can induce the creation of two universes from nothing. It is known that perturbations associated with the no-boundary scenario can only be consistent with the Bunch-Davies vacuum. Here we demonstrate that the Euclidean wormholes can allow for a de Sitter invariant vacuum, the so-called $\alpha$-vacuum state, where the Bunch-Davies vacuum is a special case. This therefore provides the $\alpha$-vacuum a geometrical origin. As an aside, we discuss a subtle phase issue when considering the power spectrum related to $\alpha$-vacuum in the closed universe framework., Comment: 25 pages, 8 figures
- Published
- 2024