Hot Cosmic Qubits: Late-Time de Sitter Evolution and Critical Slowing Down
Abstract
Temporal evolution of a comoving qubit coupled to a scalar field in de Sitter
space is studied with an emphasis on reliable extraction of late-time
behaviour. The phenomenon of critical slowing down is observed if the effective
mass is chosen to be sufficiently close to zero, which narrows the window of
parameter space in which the Markovian approximation is valid. The dynamics of
the system in this case are solved in a more general setting by accounting for
non-Markovian effects in the evolution of the qubit state. Self-interactions
for the scalar field are also incorporated, and reveal a breakdown of late-time
perturbative predictions due to the presence of secular growth.