Preservation of quantum key rate in the presence of decoherence

TL;DR

This paper investigates how weak measurement techniques can help maintain quantum key distribution rates despite environmental decoherence, showing that certain strategies outperform others in preserving quantum security.

Contribution

It demonstrates that weak measurement with post-selection can effectively slow decoherence and preserve quantum key rates in the presence of amplitude damping channels.

Findings

Weak measurement can slow decoherence effects.

Post-selection enhances key rate preservation.

Certain strategies outperform others in preserving quantum security.

Abstract

It is well known that the interaction of quantum systems with the environment reduces the inherent quantum correlations. Under special circumstances the effect of decoherence can be reversed, for example, the interaction modeled by an amplitude damping channel can boost the teleportation fidelity from the classical to the quantum region for a bipartite quantum state. Here, we first show that this phenomena fails in the case of a quantum key distribution protocol. We further show that the technique of weak measurement can be used to slow down the process of decoherence, thereby helping to preserve the quantum key rate when one or both systems are interacting with the environment via an amplitude damping channel. Most interestingly, in certain cases weak measurement with post-selection where one considers both success and failure of the technique is shown to be more useful than without it when both systems interact with the environment.