Noise-Free Measurement of Harmonic Oscillators with Instantaneous Interactions

M. Franca Santos, G. Giedke, E. Solano

Published 2006-05-31, updated 2007-01-08Version 2

We present a method of measuring the quantum state of a harmonic oscillator through instantaneous probe-system selective interactions of the Jaynes-Cummings type. We prove that this scheme is robust to general decoherence mechanisms, allowing the possibility of measuring fast-decaying systems in the weak-coupling regime. This method could be applied to different setups: motional states of trapped ions, microwave fields in cavity/circuit QED, and even intra-cavity optical fields.