Generalized Galileons: instabilities of bouncing and Genesis cosmologies and modified Genesis
- Institute for Nuclear Research of the Russian Academy of Sciences,60th October Anniversary Prospect 7a, 117312 Moscow (Russian Federation)
We study spatially flat bouncing cosmologies and models with the early-time Genesis epoch in a popular class of generalized Galileon theories. We ask whether there exist solutions of these types which are free of gradient and ghost instabilities. We find that irrespectively of the forms of the Lagrangian functions, the bouncing models either are plagued with these instabilities or have singularities. The same result holds for the original Genesis model and its variants in which the scale factor tends to a constant as t→−∞. The result remains valid in theories with additional matter that obeys the Null Energy Condition and interacts with the Galileon only gravitationally. We propose a modified Genesis model which evades our no-go argument and give an explicit example of healthy cosmology that connects the modified Genesis epoch with kination (the epoch still driven by the Galileon field, which is a conventional massless scalar field at that stage).
- Sponsoring Organization:
- SCOAP3, CERN, Geneva (Switzerland)
- OSTI ID:
- 22572134
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2016, Issue 08; Other Information: PUBLISHER-ID: JCAP08(2016)037; OAI: oai:repo.scoap3.org:16858; cc-by Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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