Autonomous Quantum Error Correction in a Four-Photon Kerr Parametric Oscillator

TL;DR

This paper presents a simplified autonomous quantum error correction scheme for a four-photon Kerr parametric oscillator that requires only a single microwave tone, potentially enabling more practical quantum computing.

Contribution

It introduces the simplest autonomous error correction scheme surpassing the break-even point using protected quasienergy states and degeneracy in a four-photon Kerr oscillator.

Findings

Scheme requires only one microwave tone for error correction.

Achieves error correction that surpasses the break-even point.

Reduces complexity of autonomous quantum error correction.

Abstract

Autonomous quantum error correction has gained considerable attention to avoid complicated measurements and feedback. Despite its simplicity compared with the conventional measurement-based quantum error correction, it is still a far from practical technique because of significant hardware overhead. We propose an autonomous quantum error correction scheme for a rotational symmetric bosonic code in a four-photon Kerr parametric oscillator. Our scheme is the simplest possible error correction scheme that can surpass the break-even point -- it requires only a single continuous microwave tone. We also introduce an unconditional reset scheme that requires one more continuous microwave tone in addition to that for the error correction. The key properties underlying this simplicity are protected quasienergy states of a four-photon Kerr parametric oscillator and the degeneracy in its quasienergy level structure. These properties eliminate the need for state-by-state correction in the Fock basis. Our schemes greatly reduce the complexity of autonomous quantum error correction and thus may accelerate the use of the bosonic code for practical quantum computation.