Kurt Jacobs

U. Mass.

Abstract: Being able to measure nonlinear observables of quantum systems, such a nano-mechnical resonators, is useful for a number of reasons. However, to do so one needs to engineer interactions between the resonator and a probe system that contains only the desired nonlinear observable. We show how one can, in principle, make continuous measurements of a wide range of nonlinear observables by using an auxiliary qubit, coupled to the resonator via a simple fixed interaction, and performing time-dependent control on the qubit.