Qubit Syndrome Measurements with a High-Fidelity Rb-Cs Rydberg Gate
Jared A. Miles, Martin Lichtman, A. M. Scott, Jillian J. Scott, Sam A. Norrell, M. J. Bedalov, D. A. Belknap, Daniel C. Cole, S. Y. Eubanks, M. Gillette, P. Gokhale, J. Goldwin, M. Iliev, R. A. Jones, Kevin W. Kuper, D. Mason, P. T. Mitchell, Joseph D. Murphree, Nathan A. Neff-Mallon, T. W. Noel · Physical Review Letters · 2026
We demonstrate an interspecies entangling Rydberg gate between rubidium (Rb) and cesium (Cs) atoms with fidelity F=0.975±0.002. The two-species atom array enables in-place quantum nondemolition (QND) qubit measurements which are a key capability for quantum error correction. We demonstrate this functionality with multiatom error syndrome measurements achieving QND measurement fidelities of F_{QND}=0.933(12) and 0.865(17) for two- and three-qubit plaquettes, respectively.