Quantum locking of mirrors in interferometers
  We show that quantum noise in very sensitive interferometric measurements such as gravitational-waves detectors can be drastically modified by quantum feedback. We present a new scheme based on active control to lock the motion of a mirror to a reference mirror at the quantum level. This simple technique allows to reduce quantum effects of radiation pressure and to greatly enhance the sensitivity of the detection. 
Jean-Michel Courty, A. Heidmann, M. Pinard