On the fate of coupled flat directions during inflation

Abstract

We investigate the stochastic dynamics of the long wavelength modes of a generic light scalar field that during inflation is coupled to another scalar field. The coupling plays an important role for the fluctuation of the field amplitude and may block its initial growth. We find that such a blocking is avoided, albeit only temporarily, if the light scalar has an initial non-vanishing expectation value <ϕ> larger than a certain critical value, for which we provide an estimate. We also show that the field fluctuations will eventually reach an equilibrium amplitude provided inflation is sufficiently long-lasting. We present a novel, general expression for the variance <ϕ^2> that takes into account the coupling of the massless field and describes the growth during the epoch of quasi-free fluctuations as well as the late-time approach to the equilibrium.

19 pages, 4 figures. Comments and references added. Accepted for publication in JCAP

References in corpus (8)

• Warm Inflation and its Microphysical Basis
• First passage time statistics of Brownian motion with purely time dependent drift and diffusion
• Trapped Inflation
• Cosmological Fluctuations from Infra-Red Cascading During Inflation
• Spectator field dynamics in de Sitter and curvaton initial conditions
• Warm inflation dynamics in the low temperature regime
• Trapped Quintessential Inflation in the context of Flux Compactifications
• Stochastic Approach to Flat Direction during Inflation

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• The inflationary origin of the Cold Spot anomaly
• Inflationary buildup of a vector field condensate and its cosmological consequences
• Hidden in the background: a local approach to CMB anomalies