Concavity of the auxiliary function appearing in quantum reliability function an classical-quantum channels

TL;DR

This paper proves the concavity of an auxiliary function related to the quantum reliability function for classical-quantum channels, providing theoretical insights into quantum information theory.

Contribution

It establishes the concavity of the auxiliary function for s between 0 and 1, a key step in understanding quantum channel reliability bounds.

Findings

Proves concavity of the auxiliary function for s in [0,1]

Enhances theoretical understanding of quantum reliability bounds

Supports development of more accurate quantum communication models

Abstract

Concavity of the auxiliary function which appears in the random coding exponent as the lower bound of the quantum reliability function for general quantum states is proven for s between 0 and 1.