Fig. 4: Ramsey interferometry.
(a) Experimental sequence for a Ramsey experiment on the computational ion which incorporates re-cooling of the coolant ion and exchange transport (not to scale). Composite π/2 pulses for preparation and analysis begin and end the interferometry. Between π/2 pulses, sideband cooling on the coolant ion and exchange transport are performed. These two operations (marked with hash coloring) are alternatively replaced with equivalent delays. An echo composite π pulse mitigates the impact of slow magnetic field drift. (b) Computational-ion Ramsey fringe, measured by varying the relative phase ϕ between preparation and analysis π/2 pulses. Blue points include re-cooling of the coolant ion and exchange transport. The red points include an equivalent delay. Error bars represent the 68% confidence interval in state populations assuming binomial statistics. Solid lines are fits to the data.
