An emergent Universe scenario is a cosmological model that features the Universe being in a low-entropy "dormant" state before the Big Bang or the beginning of the cosmic inflation. Several such scenarios have been proposed in the literature.
"Cosmic egg" scenarios
editA popular version proposed by George Ellis and others involves the Universe shaped like a 3-dimensional sphere (or another compact manifold) until a rolling scalar field begins inflating it. These models are notable as potentially avoiding both a Big Bang singularity and a quantum gravity era.[1]
Criticism
editThis proposal has been criticised by Vilenkin and Mithani[2] and on different grounds by Aguirre and Kehayias[3] as inconsistent if quantum-mechanical effects are taken into account.
References
edit- ^ Ellis, George; Maartens, Roy (January 7, 2004). "The Emergent Universe: inflationary cosmology with no singularity". Classical and Quantum Gravity. 21 (1): 223–232. arXiv:gr-qc/0211082. Bibcode:2004CQGra..21..223E. doi:10.1088/0264-9381/21/1/015. S2CID 250819315.
- ^ Mithani, Audrey T.; Vilenkin, Alexander (January 10, 2012). "Collapse of simple harmonic universe". Journal of Cosmology and Astroparticle Physics. 2012 (1): 28. arXiv:1110.4096. Bibcode:2012JCAP...01..028M. doi:10.1088/1475-7516/2012/01/028. S2CID 250740037.
- ^ Aguirre, Anthony; Kehayias, John (November 7, 2013). "Quantum Instability of the Emergent Universe". Physical Review D. 88 (10): 103504. arXiv:1306.3232. Bibcode:2013PhRvD..88j3504A. doi:10.1103/PhysRevD.88.103504. S2CID 118348623.