Reliable communication over noisy quantum channels

Hao-Chung Cheng^1*

¹Electrical Engineering, National Taiwan University, Taipei, Taiwan

* Presenter:Hao-Chung Cheng, email:haochung@ntu.edu.tw

To protect information against quantum noise in communication, Alice at the transmitter first encodes information to be sent into large block codes; Bob then coherently decodes the noisy information at the receiver. The channel capacity theorem demonstrates that reliable communication is possible, as the code length approaches asymptotic infinity. A previous work [Nat. Commun. 7, 2016] analyzed finite-length codes for achieving a code rate close to the channel capacity. However, the required code length to achieve an ɛ error is of order O(1/ɛ^2), which is still quite challenging in practice for reliable communication with a small error.
In this talk, we show that the code length scales only logarithmically in ɛ, exponentially improving on the previous result. Moreover, the established error exponent is essentially optimal for all high rates. Our result extends to classical communication over any quantum channel with or without entanglement assistance.
This talk is based on [PRX Quantum, 4, 040330 (2023)] and [arXiv:2507.06232].

Keywords: N/A, N/A, N/A