Entanglement-Assisted Capacity of Quantum Channels with Side Information

TL;DR

This paper characterizes the entanglement-assisted capacity of quantum channels with side information at the encoder, providing new insights for both causal and non-causal scenarios in quantum communication.

Contribution

It introduces a new characterization of capacity with causal side information and offers an alternative proof for the non-causal case, advancing quantum information theory.

Findings

Capacity characterization for causal side information

Alternative proof for non-causal capacity

Enhanced understanding of quantum channel capacities

Abstract

Entanglement-assisted communication over a random-parameter quantum channel with either causal or non-causal channel side information (CSI) at the encoder is considered. This describes a scenario where the quantum channel depends on the quantum state of the input environment. While Bob, the decoder, has no access to this state, Alice, the transmitter, performs a sequence of projective measurements on her environment and encodes her message accordingly. Dupuis established the entanglement-assisted capacity with non-causal CSI. Here, we establish characterization in the causal setting, and also give an alternative proof technique and further observations for the non-causal setting.