A quantum beam separator

We propose a realistic scheme for a quantum beam separator for light. Our model consists of a single atom traversing a resonator. Depending on the internal state of the atom light will be reflected off or transmitted through the resonator. We have investigated the performance of this device under realistic operating conditions using quantum Monte Carlo wavefunction simulations. We have found the time dependence of the coupling and the measurement back action of the continuous measurement process of the output light to significantly influence the behaviour of the device. (author)