Decoherence and decay of motional quantum states of a trapped atom coupledto engineered reservoirs - art. no. 053807

We present results from an experimental study of the decoherence and decay of quantum states of a trapped atomic ion's harmonic motion interacting wit h several types of engineer ed reservoirs. We experimentally simulate three types of reservoirs: a high-temperature amplitude reservoir, a zero-temper ature amplitude reservoir, and a high-temperature phase reservoir. Interact ion with these environments causes the ion's motional state to decay or hea t, and in the case of superposition states, to lose coherence. We report me asurements of the decoherence of superpositions of coherent states and two- Fock-state superpositions into these reservoirs, as well as the decay and h eating of Fock states. We confirm the theoretically well-known scaling laws that predict that the decoherence rate of superposition states scales with the square of the "size"' of the state.