Comment on "extended Born-Infeld theory and the bouncing magnetic universe"

Ricardo García-Salcedo, Tame Gonzalez, Antonio Horta-Rangel, Israel Quiros

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

© 2014 American Physical Society. In a recent paper [Phys. Rev. D 85, 023528 (2012)PRVDAQ1550-799810.1103/PhysRevD.85.023528] the authors proposed a generalized Born-Infeld electrodynamics coupled to general relativity which produces a nonsingular bouncing universe. For a magnetic universe the resulting cosmic evolution inevitably interpolates between asymptotic de Sitter states. Here we show that (i) the conclusion about the inevitability of the asymptotic vacuum regime in a magnetic universe is wrong, (ii) a sudden curvature singularity - not better than the big bang - arises, but for spaces of positive curvature, (iii) the square sound speed can be a negative quantity, signaling instability against small perturbations of the background energy density, and (iv) the speed of sound can exceed the speed of light, which raises a causality issue.
Original languageAmerican English
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
DOIs
StatePublished - 1 Dec 2014

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Born-Infeld theory
universe
curvature
acoustics
electrodynamics
relativity
flux density
perturbation
vacuum

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Comment on "extended Born-Infeld theory and the bouncing magnetic universe". / García-Salcedo, Ricardo; Gonzalez, Tame; Horta-Rangel, Antonio; Quiros, Israel.

In: Physical Review D - Particles, Fields, Gravitation and Cosmology, 01.12.2014.

Research output: Contribution to journalArticle

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