Stochastic dark energy from inflationary quantum fluctuations

Understand

We study the quantum backreaction from inflationary fluctuations of a very light, non-minimally coupled spectator scalar and show that it is a viable candiate for dark energy.

• The problem is solved by suitably adapting the formalism of stochastic inflation.
• This allows us to self-consistently account for the backreaction on the background expansion rate of the Universe where its effects are large.
• This framework is equivalent to that of semiclassical gravity in which matter vacuum fluctuations are included at the one loop level, but purely quantum gravitational fluctuations are neglected.