New lower bounds on the non-zero capacity of Pauli Channels

TL;DR

This paper establishes new lower bounds on the non-zero quantum capacity of Pauli channels, demonstrating correctability up to the hashing bound and achieving a fidelity of approximately 0.8087 for depolarizing channels.

Contribution

It introduces an entropic method to determine the threshold for non-zero capacity, improving understanding of quantum error correction limits for Pauli noise.

Findings

Pauli noise is correctable up to the hashing bound

Achieves non-zero capacity at fidelity f=0.80870 for depolarizing channels

Provides a new entropic approach to threshold calculation

Abstract

We study encodings that give the best known thresholds for the non-zero capacity of quantum channels, i.e., the upper bound for correctable noise, using an entropic approach to calculation of the threshold values. Our results show that Pauli noise is correctable up to the hashing bound. For a depolarizing channel, this approach allows one to achieve a non-zero capacity for a fidelity (probability of no error) of f=0.80870.