Robustness of quantum communication based on a decoherence-free subspace using a counter-propagating weak coherent light pulse

TL;DR

This paper presents a robust quantum communication scheme using a decoherence-free subspace that effectively counters collective noises and leverages channel reciprocity, achieving higher success probability with linear optics.

Contribution

It introduces an efficient, noise-resistant quantum communication protocol employing a counter-propagating weak coherent pulse and decoherence-free subspace, enhancing robustness and success rate.

Findings

Scheme is robust against collective and general collective noises.

Success probability scales with single-photon channel transmittance.

Implementation is feasible with linear optical elements.

Abstract

We study distribution schemes for a polarization entangled photon pair based on a decoherence-free subspace over lossy quantum channels and propose an efficient scheme that is robust against not only collective phase noises but also general collective noises for two qubits. While the proposed scheme employs two photons to build the decoherence-free subspace, the success probability is proportional to the channel transmittance of a single photon with the aid of a counter-propagating weak coherent light pulse. The key ingredient in the scheme is found to be the reciprocity of the channel. The proposed scheme shares the rest of the properties with the previously proposed schemes, i.e., it can be realized by linear optical elements and it is robust against the fluctuations in the optical circuits used by the two parties.