Stochastic Inflation and Replica Field Theory

Understand

We adopt methods from statistical field theory to stochastic inflation.

• For the example of a free test field in de Sitter and power-law inflation, the power spectrum of long-wavelength fluctuations is computed.
• We study its dependence on the shape of the filter that separates long from short wavelength modes.
• While for filters with infinite support the phenomenon of dimensional reductions is found on large super-horizon scales, filters with compact support return a scale-invariant power spectrum in the infra-red.