Abstract:

In this talk a new protocol for weak continuous quantum non-demolition (QND) measurements of a joint observable of a quantum system and a meter system will be presented. It employs the characteristic time evolution of the expectation value of a meter observable, and the changes in this evolution to infer the currently populated eigenstate and the jumps between eigenstates of the QND observable. The protocol is applied by simulating detection of the photon number in a cavity, by weakly probing the Rabi oscillations of a two-level system that is coupled resonantly to the cavity field.