Near-optimal performance of quantum error correction codes

Physical Review Letters (2024)

 

The Knill-Laflamme conditions are rules used to identify perfect quantum error correction codes, which are crucial for developing advanced quantum codes. However, these perfect codes are limited and might not always be the best performers. So it’s useful to create a more flexible and practical way to measure code performance.

In this research, a team introduces a new metric called “near-optimal channel fidelity,” a simple and efficient way to measure the performance of any quantum code and noise. This metric gives a convenient, reliable estimate of how well a code will perform and can be calculated using the same information as the Knill-Laflamme conditions.

The group shows that this new metric is more computationally efficient than traditional methods that rely on complex optimization, allowing them to simulate much larger systems.

Additionally, the group provides analytical results for specific codes such as the thermodynamic code and the Gottesman-Kitaev-Preskill (GKP) code. The GKP code shows improved performance with increasing energy and reaches a limit at infinite energy, which is different from other similar codes.

The paper authors are Guo Zheng, Wenhao He, Gideon Lee and Liang Jiang, who conducted the work at the University of Chicago, Peking University and MIT.