Quantum analysis of the recent cosmological bounce in the comoving Hubble length
| Autor: | Steffen Gielen, João Magueijo |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Physical Review D. 107 |
| ISSN: | 2470-0029 2470-0010 |
| Popis: | We formulate the transition from decelerated to accelerated expansion as a bounce in connection space and study its quantum cosmology, knowing that reflections are notorious for bringing quantum effects to the fore. We use a formalism for obtaining a time variable via the demotion of the constants of Nature to integration constants, and focus on a toy Universe containing only radiation and a cosmological constant $\Lambda$ for its simplicity. We find that, beside the usual factor ordering ambiguities, there is an ambiguity in the order of the quantum equation, leading to two distinct theories: one second, the other first order. In both cases two time variables may be defined, conjugate to $\Lambda$ and to the radiation constant of motion. We make little headway with the second-order theory, but are able to produce solutions to the first-order theory. They exhibit the well-known "ringing" whereby incident and reflected waves interfere, leading to oscillations in the probability distribution even for well-peaked wave packets. We also examine in detail the probability measure within the semiclassical approximation. Close to the bounce, the probability distribution becomes double-peaked, with one peak following a trajectory close to the classical limit but with a Hubble parameter slightly shifted downwards, and the other with a value of $b$ stuck at its minimum. An examination of the effects still closer to the bounce, and within a more realistic model involving matter and $\Lambda$, is left to future work. Comment: 15 pages, 13 figures; v3: very minor changes in presentation (mostly typographical), close to version published in Phys.Rev.D |
| Databáze: | OpenAIRE |
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