{\AE} codes

TL;DR

This paper evaluates the limitations of diatomic molecular codes in protecting quantum information against native atomic and molecular noise, and introduces more practical absorption-emission ({ extless}AE{ extgreater}) codes with broader applicability.

Contribution

It derives conditions for quantum codes to resist native noise and proposes new { extless}AE{ extgreater} codes that outperform molecular codes in practicality and noise protection.

Findings

Diatomic molecular codes fail against native atomic/molecular noise.

Derived necessary and sufficient conditions for noise-resistant codes.

Proposed { extless}AE{ extgreater} codes are more practical and versatile.

Abstract

Diatomic molecular codes [arXiv:1911.00099] are designed to encode quantum information in the orientation of a diatomic molecule, allowing error correction from small torques and changes in angular momentum. Here, we directly study noise native to atomic and molecular platforms -- spontaneous emission, stray electromagnetic fields, and Raman scattering -- and show that diatomic molecular codes fail against this noise. We derive simple necessary and sufficient conditions for codes to protect against such noise. We also identify existing and develop new absorption-emission (\AE) codes that are more practical than molecular codes, require lower average momentum, can directly protect against photonic processes up to arbitrary order, and are applicable to a broader set of atomic and molecular systems.