The Kerr-cat qubit: efficient readout and two-qubit gates*

Superpositions of two opposite-phase coherent states in an oscillator, so-called Schrödinger cat states, can encode a noise-biased qubit, meaning a qubit with a strong protection against one error channel. Such a protected "cat qubit" has the ability to significantly reduce the overhead associated with quantum error correction in, for instance, a surface-code-style architecture. This overhead reduction relies on the ability to perform all gates in a manner that preserves the noise bias. In this talk, we review our implementation for the Kerr-cat qubit, which is based on the interplay between two-photon driving and Kerr nonlinearity. This scheme is compatible with fast, high-fidelity single qubit gates and achieves a strong noise bias. We will report on experimental improvements, the efficiency of the quantum non-demolition (QND) readout of this qubit, and our progress towards the realization of a noise-biased CNOT gate between two such Kerr-cat qubits.