Optical hybrid approaches to quantum information

TL;DR

This paper reviews recent hybrid optical methods that combine discrete and continuous quantum variables to enhance the feasibility, efficiency, and fidelity of quantum information processing beyond traditional linear schemes.

Contribution

It summarizes recent developments in hybrid approaches that incorporate measurement-induced nonlinearities to overcome limitations of linear optical quantum information processing.

Findings

Hybrid approaches improve quantum information processing capabilities.

Measurement-induced nonlinearities enhance scheme efficiencies.

Potential to surpass limitations of linear optics and Gaussian operations.

Abstract

This article reviews recent hybrid approaches to optical quantum information processing, in which both discrete and continuous degrees of freedom are exploited. There are well-known limitations to optical single-photon-based qubit and multi-photon-based qumode implementations of quantum communication and quantum computation, when the toolbox is restricted to the most practical set of linear operations and resources such as linear optics and Gaussian operations and states. The recent hybrid approaches aim at pushing the feasibility, the efficiencies, and the fidelities of the linear schemes to the limits, potentially adding weak or measurement-induced nonlinearities to the toolbox.