Fig. 2: High-fidelity two-qubit operation between nuclear (CZ) and electron (CROT) spins.
a, Normalized 2Q-RB of the electron–electron CROT gate from the reference (black) and interleaved procedure (CROT e2) showing the Clifford fidelity. b, Normalized 2Q-RB of the geometric CZ operation on the nuclear-spin pair n6 and n9 from the reference (black) and interleaved procedure (CZ). All other nuclear spins are initialized to down ⇓ in this experiment. c, Summary of the nuclear (CZ) and electron 2Q-RB (zCROT and CROT of e1 and e2) fidelities. For the electron CROT gate, the primitive fidelities (reference for interleaved 2Q-RB) are also shown for different nuclear spin configurations, with the corresponding frequency gap ΔEz = |fCROT e1 − fCROT e2| indicated at the top.
