Infrared dynamics of a light scalar field in de Sitter. (arXiv:1911.00564v1 [hep-th])
<a href="http://arxiv.org/find/hep-th/1/au:+Mirbabayi_M/0/1/0/all/0/1">Mehrdad Mirbabayi</a>
Inertial observers in de Sitter are surrounded by a horizon and see thermal
fluctuations. To them, a massless scalar field appears to follow a random
motion, but any attractive potential, no matter how weak, will eventually
stabilize the field. We study this thermalization process in the static
patch—the spacetime region accessible to an individual observer—via a
truncation to the low frequency spectrum. We focus on the distribution of the
field averaged over a subhorizon region. At time scales much longer than the
inverse temperature, we find the evolution to be Markovian, governed by the
same Fokker-Planck equation that arises when the theory is studied in the
cosmological setup.
Inertial observers in de Sitter are surrounded by a horizon and see thermal
fluctuations. To them, a massless scalar field appears to follow a random
motion, but any attractive potential, no matter how weak, will eventually
stabilize the field. We study this thermalization process in the static
patch—the spacetime region accessible to an individual observer—via a
truncation to the low frequency spectrum. We focus on the distribution of the
field averaged over a subhorizon region. At time scales much longer than the
inverse temperature, we find the evolution to be Markovian, governed by the
same Fokker-Planck equation that arises when the theory is studied in the
cosmological setup.
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