Two-qubit gate for the 0-π qubit: Part 1

The 0 − π qubit is an attractive candidate to replace the Transmon as a higher quality qubit. Single qubit gates have been experimentally demonstrated on this qubit, in the “soft” regime. However, to date there are no proposals for a practical two-qubit gate for 0 – π qubits, and two qubit gates are critical for quantum algorithms. In this talk we demonstrate a fast microwave-activated controlled-Z gate for the capacitively coupled soft 0 − π qubit. We show gate fidelities over 99% for gate times below 100ns. We find that off resonant drive can achieve higher fidelity than resonant drive. The gate analysis in terms of circuit parameter disorders and local noise operators is also provided.

References:

P. Groszkowski et al. New J. Phys. 20.4 (2018), p. 043053.

A. Gyenis et al. PRX Quantum 2.1 (2021), p. 010339.

K. N. Nesterov et al. Phys. Rev. A 98.3, (2018) p. 030301