Qubit ZooDemonstrates high-fidelity CZ (99.76%) and ZZ-free iSWAP (99.87%) gates using a frequency-tunable transmon coupler between two fixed-frequency transmons. The tunable coupler enables near-complete suppression of static ZZ interaction — a major source of correlated errors in multi-qubit systems.
Key Results
- CZ gate fidelity: 99.76(3)% (interleaved RB)
- iSWAP gate fidelity: 99.87(3)%
- Residual ZZ coupling < 10 kHz (vs ~100 kHz without coupler)
- Gate time: ~200 ns (CZ), ~120 ns (iSWAP)
- Architecture adopted by Google and IBM for next-generation processors
Links
- Journal: Physical Review X
- arXiv: 2011.01261