Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/12340
 Title: Quasiopen inflation Author: García-Bellido, JuanGarriga Torres, JaumeMontes, Xavier Keywords: Teoria de camps (Física)CosmologiaField theory (Physics)Cosmology Issue Date: 1998 Publisher: The American Physical Society Abstract: We show that a large class of two-field models of single-bubble open inflation do not lead to infinite open universes, as it was previously thought, but to an ensemble of very large but finite inflating islands'. The reason is that the quantum tunneling responsible for the nucleation of the bubble does not occur simultaneously along both field directions and equal-time hypersurfaces in the open universe are not synchronized with equal-density or fixed-field hypersurfaces. The most probable tunneling trajectory corresponds to a zero value of the inflaton field; large values, necessary for the second period of inflation inside the bubble, only arise as localized fluctuations. The interior of each nucleated bubble will contain an infinite number of such inflating regions of comoving size of order $\gamma^{-1}$, where $\gamma$ depends on the parameters of the model. Each one of these islands will be a quasi-open universe. Since the volume of the hyperboloid is infinite, inflating islands with all possible values of the field at their center will be realized inside of a single bubble. We may happen to live in one of those patches of comoving size $d\lesssim \gamma^{-1}$, where the universe appears to be open. In particular, we consider the `supernatural'' model proposed by Linde and Mezhlumian. There, an approximate U(1) symmetry is broken by a tunneling field in a first order phase transition, and slow-roll inflation inside the nucleated bubble is driven by the pseudo-Goldstone field. We find that the excitations of the pseudo-Goldstone produced by the nucleation and subsequent expansion of the bubble place severe constraints on this model. We also discuss the coupled and uncoupled two-field models. Note: Reproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevD.57.4669 It is part of: Physical Review D, 1998, vol. 57, núm. 8, p. 4669 Related resource: http://doi.org/10.1103/PhysRevD.57.4669 URI: http://hdl.handle.net/2445/12340 ISSN: 0556-2821 Appears in Collections: Articles publicats en revistes (Física de la Matèria Condensada)

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