  We propose a time-delayed feedback control scheme for open quantum systems
that can dramatically reduce the time to reach steady state. No measurement is
performed in the feedback loop, and we suggest a simple all-optical
implementation for a cavity QED system. We demonstrate the potential of the
scheme by applying it to a driven and dissipative Dicke model, as recently
realized in a quantum gas experiment. The time to reach steady state can then
reduced by two orders of magnitude for parameters taken from experiment, making
previously inaccessible long time attractors reachable within typical
experimental run times. The scheme also offers the possibility of slowing down
the dynamics, as well as qualitatively changing the phase diagram of the
corresponding physical system.
