High-Fidelity Preservation of Quantum Information During Trapped-Ion Transport

A promising scheme to build scalable quantum simulators and computers is the synthesis of a scalable system using interconnected subsystems. A prerequisite for this approach is the ability to faithfully transfer quantum information between subsystems. With trapped atomic ions this can be realized by transporting ions with quantum information encoded into their internal states. Here, we measure with high precision the fidelity of quantum information encoded into hyperfine states of a 171Yb+ ion during ion transport in a micro-structured Paul trap. Ramsey spectroscopy of the ion's internal state is interleaved with up to 4000 transport operations over a distance of 280 {\mu}m each taking 12.8 {\mu}s. We obtain a state fidelity of 99.9994(+6/-7)% per ion transport.