Increasing transport speeds in the trapped-ion quantum CCD computer architecture

In a recent demonstration of the quantum charge coupled device (QCCD) trapped ion architecture [1], transport operations and cooling comprise the majority of the circuit time.  Cooling is required due to excitation arising from nonideal transport operations.  To mitigate this requirement and decrease circuit times, there is significant interest in achieving fast transport operations resulting in low excitation.  A complication of the work of Ref. [1] is that in order to sympathetically cool during circuits, multi-species ion crystals are used.  As a result, there are more ion crystal modes that can be excited by transport operations.  Designing transport operations that have low intrinsic excitation is the goal.  However, in practice, any residual coherent excitation can be removed by a suitably applied coherent force.  Previous work has demonstrated fast transport of single ions or multiple ions of the same species, while deexciting the resulting coherent motion [2,3].  Here, we report progress on applying coherent deexcitation and other techniques to improve the transport speed in our QCCD system. 

[1] J. M. Pino et al, Nature 592, 209-213 (2021).

[2] A. Walther et al, PRL 109, 080501 (2012).

[3] R. Bowler et al, PRL 109, 080502 (2012).