Protecting a bosonic qubit with autonomous quantum error correction I – Theory

Existing demonstrations of quantum error correction are based on an active schedule of measurement and recovery operations which is hardware intensive and incurs additional error overhead. It is theoretically possible to correct quantum errors with dissipation in a continuous and autonomous fashion, without a classical controller. While dissipative confinement of a quantum system to a two-state manifold had been demonstrated, so far it has remained challenging to achieve a dissipation operator that counters the dominant natural errors in order to extend the lifetime of an encoded qubit. Here we present an autonomous error correction scheme for a bosonic qubit in a superconducting cavity, which directly corrects the dominant error channel of the system: single photon loss. In this Part I of the talk, we discuss this dissipative error correction protocol, its design considerations, as well as its expected performance and limitations.