Infrared dynamics of a light scalar field in de Sitter
Mehrdad Mirbabayi
Abstract
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 timescales much longer than the inverse temperature and to leading order in the coupling, we find the evolution to be Markovian, governed by the same Fokker-Planck equation that arises when the theory is studied in the inflationary setup.
Topics & Concepts
PhysicsDe Sitter universeScalar fieldDe Sitter spaceMassless particleScalar (mathematics)de Sitter invariant special relativitySpacetimeClassical mechanicsQuantum field theory in curved spacetimeHorizonQuantum electrodynamicsMathematical physicsField (mathematics)Anti-de Sitter spaceThermalisationMinkowski spaceInfraredDynamics (music)Inertial frame of referenceDistribution (mathematics)Inflation (cosmology)Quantum mechanicsAnnihilationCosmologyCosmological perturbation theoryBraneQuantum fluctuationOrder (exchange)Scalar bosonCosmology and Gravitation TheoriesGalaxies: Formation, Evolution, PhenomenaPulsars and Gravitational Waves Research