Gate operations in sympathetically-cooled Yb⁺ chains

Preserving high gate fidelity while maintaining qubit connectivity is a major goal in scaling up quantum computers and simulators. In systems based on long chains of trapped ions, this is challenging due to heating via the coupling of ions to noisy electric fields, especially in the weakly-confined axial direction. In systems based on 171Yb⁺, this challenge can be countered by sympathetic cooling using 172Yb⁺ coolants [1].

We present progress towards an algorithmically useful implementation of this scheme in a room-temperature Yb⁺ system based on the Sandia HOA-2.1.1 trap. We demonstrate isotope-selective loading of 172Yb⁺ ions, protocols for reordering mixed-isotope chains to counter background-gas collisions, 3D sympathetic cooling, and integration of sympathetic cooling with gate operations.

This work is supported by the ARO with funding from the IARPA LogiQ program, the NSF QLCI program, and the DOE QSA program.

References

[1] M. Cetina et.al., PRX QUANTUM 3, 010334 (2022).