Effective master equations for two accelerated qubits

Understand

We revisit the problem involving two constantly accelerating Unruh-DeWitt detectors using Open Effective Field Theory methods.

• We study the time evolution of the joint detector state using a Markovian approximation which differs from the standard one taken in the literature.
• We show that this Markovian limit already implies the complete positivity of the dynamical evolution map without invoking the rotating wave approximation (RWA), in contrast to standard derivations of open system master equations.
• By calculating explicitly the domain of validity of this Markovian approximation, we argue that the lack of complete positivity in the usual microscopic derivation stems from the (subtle) fact that the Redfield equation is used outside its domain of validity.