Quantum error correction and detection: quantitative analysis of a coherent-state amplitude damping code

TL;DR

This paper analyzes a non-Gaussian quantum error correction code for optical coherent-state qubits, providing tighter performance bounds and evaluating its effectiveness in error correction and detection modes under realistic conditions.

Contribution

It offers a refined performance analysis of a quantum error correction code with improved bounds, considering practical gate constraints and different operational modes.

Findings

Error correction mode only outperforms direct transmission for specific parameters.

Error detection mode benefits from higher repetition encodings across various conditions.

Tighter bounds on code performance under realistic assumptions.

Abstract

We re-examine a non-Gaussian quantum error correction code designed to protect optical coherent-state qubits against errors due to an amplitude damping channel. We improve on a previous result [Phys. Rev. A 81, 062344 (2010)] by providing a tighter upper bound on the performance attained when considering realistic assumptions which constrain the operation of the gates employed in the scheme. The quantitative characterization is performed through measures of fidelity and concurrence, the latter obtained by employing the code as an entanglement distillation protocol. We find that, when running the code in fully-deterministic error correction mode, direct transmission can only be beaten for certain combinations of channel and input state parameters, whereas in error detection mode, the usage of higher repetition encodings remains beneficial throughout.