Decoherence of motional superpositions of a trapped ion

We summarize experiments on the decoherence of motional superposition states of single trapped ions which were carried out at NIST. The decoherence was characterized by the loss of contrast in interference experiments involving superpositions of two motional coherent states or two motional Fock states that were subjected to stochastically fluctuating electric fields. The observed loss of coherence is in good agreement with that predicted by the appropriate master equations of quantum optics.