Oscillatory attractors: a new cosmological phase
Name
1512.02304.pdf
Description
Accepted version
Size
1.61 MB
Format
Unknown
Checksum (MD5)
a20d1d9007edea6ec127181f55878e59
Author(s)
Bains, Jasdeep S
Hertzberg, Mark Peter
Wilczek, Frank
Date Issued
2017
Journal
Journal of Cosmology and Astroparticle Physics
Publisher
IOP Publishing
Version
Author's final manuscript
Abstract
© 2017 IOP Publishing Ltd and Sissa Medialab srl. In expanding FRW spacetimes, it is usually the case that homogeneous scalar fields redshift and their amplitudes approach limiting values: Hubble friction usually ensures that the field relaxes to its minimum energy configuration, which is usually a static configuration. Here we discover a class of relativistic scalar field models in which the attractor behavior is the field oscillating indefinitely, with finite amplitude, in an expanding FRW spacetime, despite the presence of Hubble friction. This is an example of spontaneous breaking of time translation symmetry. We find that the effective equation of state of the field has average value ( w)=-1, implying that the field itself could drive an inflationary or dark energy dominated phase. This behavior is reminiscent of ghost condensate models, but in the new models, unlike in the ghost condensate models, the energy-momentum tensor is time dependent, so that these new models embody a more definitive breaking of time translation symmetry. We explore (quantum) fluctuations around the homogeneous background solution, and find that low k-modes can be stable, while high k-modes are typically unstable. We discuss possible interpretations and implications of that instability.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1088/1475-7516/2017/05/011
