Leveraging biased noise ancilla in quantum error correction: Modeling and experimental investigations of coupling between a transmon and Kerr-Cat qubit: Part 1/2*

Quantum error correction (QEC) protocols typically introduce an ancilla qubit to measure parity operators of data qubits which store quantum information. Unfortunately, ancilla errors can significantly impede the fault-tolerance of the QEC process. Recent work [1] has shown that the biased noise property of the Kerr-Cat qubit helps to mitigate ancilla back-action errors and bolster fault tolerance of QEC protocols. We will present simulated and experimental investigations on the coupling of a transmon and Kerr-Cat qubit with the aim to demonstrate the potential benefits of biased noise ancilla in QEC.

In the first part of this two-part talk, we will introduce modeling which describes the effective coupling and drive strength of a two-qubit gate between a transmon and Kerr-Cat qubit, and hence the gate speed and fidelity.

[1] S. Puri, et al., Phys. Rev. X, 9, 041009 (2019).