  The problem of quantum measurement can be partially resolved by incorporating
a process of spontaneous disentanglement into quantum dynamics. We propose a
modified master equation, which contains a nonlinear term giving rise to both
spontaneous disentanglement and thermalisation. We find that the added
nonlinear term enables limit cycle steady states, which are prohibited in
standard quantum mechanics. This finding suggests that an experimental
observation of such a limit cycle steady state can provide an important
evidence supporting the spontaneous disentanglement hypothesis.
