  Very recently [Phys. Rev. E 82, 021921 (2010)] a simple mechanism was
presented by which a molecule subjected to forced oscillations, out of thermal
equilibrium, can maintain quantum entanglement between two of its quantum
degrees of freedom. Crucially, entanglement can be maintained even in the
presence of very intense noise, so intense that no entanglement is possible
when the forced oscillations cease. This mechanism may allow for the presence
of non-trivial quantum entanglement in biological systems. Here we
significantly enlarge the study of this model. In particular, we show that the
persistent generation of dynamic entanglement is not restricted to the bosonic
heat bath model, but it can also be observed in other decoherence models, e.g.
the spin gas model, and in non-Markovian scenarios. We also show how
conformational changes can be used by an elementary machine to generate
entanglement even in unfavorable conditions. In biological systems, similar
mechanisms could be exploited by more complex molecular machines or motors.
