An experimental implementation for stabilizing Schrödinger cat states in a Kerr nonlinear resonator - Basic concepts

Schrödinger cat states of microwave light based on superpositions of coherent states in a superconducting resonator can be used as error-protected qubits as well as auxiliary systems for fault-tolerant quantum computation. It has recently been shown that such states can be stabilized by applying a two-photon drive to a Kerr nonlinear resonator. In this talk, we will give an introduction on this type of qubit and its potential uses in quantum computation before discussing an experimental implementation. Our system is based on a modified, low-anharmonicity, transmon qubit. Instead of a Josephson junction, we use a Superconducting Nonlinear Asymmetric Inductive eLement (SNAIL) providing us with both three- and four-wave-mixing terms. This simultaneously implements the required nonlinearity and gives us access to a strong two-photon drive. We will report on the details of this implementation and present our progress towards the realization of this stabilization scheme. Part one of this two-part presentation will introduce the basic concept of this qubit and its uses in quantum information.