Experimental progress towards a bias-preserving CNOT gate between two Kerr-cat qubits*

The Kerr-cat qubit, implemented via a driven SNAIL in circuit QED, is a particularly promising candidate for hardware-efficient quantum error correction due to its noise bias [1, 2]. While single-qubit performance is steadily improving [3, 4], a bias-preserving two-qubit gate is required to harvest the full potential of the noise bias for improved error correction thresholds [2].

A theoretical proposal offers a solution [5]—a fast, high-fidelity & bias-preserving CNOT gate can be realized parametrically in the SNAIL implementation. In this talk, we will present the operation of two coupled Kerr-cat qubits, and I report on our experimental progress toward realizing the bias-preserving CNOT gate. Importantly, our approach relies on the native four-wave mixing capabilities of the SNAIL, eliminating the need for extra coupling elements.