A comparative study of protocols for secure quantum communication under noisy environment: single-qubit-based protocols versus entangled-state-based protocols

TL;DR

This study compares single-qubit and entangled-state quantum communication protocols under various noise models, revealing their relative robustness and the influence of quantum resources like squeezing on fidelity.

Contribution

It provides a comprehensive comparison of protocol robustness against different noise types, highlighting conditions favoring either single-qubit or entangled protocols and the beneficial role of squeezing.

Findings

Single-qubit protocols perform better under amplitude and phase damping noise.

Entangled protocols are more robust against collective noise.

Squeezing can enhance fidelity in noisy quantum channels.

Abstract

The effect of noise on various protocols of secure quantum communication has been studied. Specifically, we have investigated the effect of amplitude damping, phase damping, squeezed generalized amplitude damping, Pauli type as well as various collective noise models on the protocols of quantum key distribution, quantum key agreement,quantum secure direct quantum communication and quantum dialogue. From each type of protocol of secure quantum communication, we have chosen two protocols for our comparative study; one based on single qubit states and the other one on entangled states. The comparative study reported here has revealed that single-qubit-based schemes are generally found to perform better in the presence of amplitude damping, phase damping, squeezed generalized amplitude damping noises, while entanglement-based protocols turn out to be preferable in the presence of collective noises. It is also observed that the effect of noise entirely depends upon the number of rounds of quantum communication involved in a scheme of quantum communication. Further, it is observed that squeezing, a completely quantum mechanical resource present in the squeezed generalized amplitude channel, can be used in a beneficial way as it may yield higher fidelity compared to the corresponding zero squeezing case.