Fig. 3: Calibration of the 2-qubit iSWAP-based JPM scheme.
From: Fast joint parity measurement via collective interactions induced by stimulated emission
a The expectation of the Pauli set measured in a 2-qubit iSWAP-based JPM scheme with the initial states \(\left\vert+++\right\rangle\). Here, the numbers on the horizontal axis represent the order of the Pauli set in terms of I, X, Y, Z for each qubit. For instance, the first Pauli operator is III, and the last one is ZZZ. b Phase accumulation during the JPM unitary gate is extracted via the quantum state tomography (QST) with the initial states \(\left\vert+++\right\rangle\). c Quantum process tomography (QPT) of the 2-qubit JPM unitary gate characterizing the experimental χexp, reaching an average 95.0% raw gate fidelity in 79 ns. We further extract the optimized QPT data with 98.5% gate fidelity after eliminating the SPAM error.
