Entanglement dynamics of nonidentical oscillators under decohering environments

We study the evolution of entanglement for a pair of coupled nonidentical harmonic oscillators in contact with
an environment. For both cases of a common bath and of two separate baths for each of the oscillators, a full master
equation is provided without rotating-wave approximation. The entanglement dynamics is analyzed as a function
of the diversity between the oscillators’ frequencies and their positive or negative mutual coupling and also the
correlation between the occupation numbers. The singular effect of the resonance condition (identical oscillators)
and its relationship with the possibility of preserving asymptotic entanglement are discussed. The importance of
the bath’s memory properties is investigated by comparing Markovian and non-Markovian evolutions.