Nonlinear Optics Quantum Computing with Circuit-QED

TL;DR

This paper proposes a circuit-QED-based nonlinear optics approach for microwave quantum computing, enabling a deterministic two-photon phase gate with improved noise tolerance and fast operation.

Contribution

It introduces a hybrid quantum system combining an LC resonator and a superconducting flux qubit to realize nonlinear coupling for quantum computing.

Findings

Achieves a deterministic two-photon phase gate.

Improves noise tolerance compared to self-Kerr nonlinearity.

Maintains fast operation speeds.

Abstract

One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.