Nonoscillating vacuum states and the quantum homogeneity and isotropy hypothesis in loop quantum cosmology

Autor: Guillermo A. Mena Marugán, Santiago Prado, Beatriz Elizaga Navascués
Přispěvatelé: Ministerio de Ciencia e Innovación (España), Japan Society for the Promotion of Science, Ministerio de Economía y Competitividad (España)
Rok vydání: 2021
Předmět:
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
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ISSN: 2470-0029
2470-0010
DOI: 10.1103/physrevd.104.083541
Popis: 11 pags., 2 figs.
We study the compatibility of the quantum homogeneitiy and isotropy hypothesis (QHIH), proposed by Ashtekar and Gupt to restrict the choice of vacuum state for the cosmological perturbations in loop quantum cosmology (LQC), with the requirement that the selected vacuum should lead to a power spectrum that does not oscillate. We inspect in close detail the procedure that these authors followed to construct a set of states satisfying the QHIH, and how a preferred vacuum can be determined within this set. We find a step that is not univocally specified in this procedure, in relation with the replacement of the set of states that was originally allowed by the QHIH with an alternative set that is more manageable. In fact, the first of these sets does not contain the state that has been used in most of the implementations of the QHIH to the analysis of the power spectrum of the perturbations in LQC. We focus our attention on the original set picked out by the QHIH and investigate whether some of its elements may display a nonoscillatory behavior. We show that, to the extent to which the techniques used in this paper apply, this possibility is feasible. Thus, the two aforementioned criteria for the physical restriction of the vacuum state in LQC are compatible with each other and not exclusive.
This work was partially supported by Projects No. MICINN FIS2017-86497-C2-2-P and No. MICINN PID2020–118159 GB-C41 from Spain. B. E. N. acknowledges financial support from the Standard Program of JSPS Postdoctoral Fellowships for Research in Japan.
Databáze: OpenAIRE