Quantum Communication with Coherent States and Linear Optics

TL;DR

This paper presents a general method to convert quantum communication protocols involving qubits into protocols using coherent states and linear optics, facilitating experimental implementation with current technology.

Contribution

The authors introduce a universal mapping that translates qubit-based protocols into optical coherent state protocols, enabling practical realization of quantum communication schemes.

Findings

The mapping preserves key properties of original protocols.

New protocols for quantum communication complexity and digital signatures are constructed.

Potential for experimental demonstration of a broad class of protocols.

Abstract

We introduce a general mapping for encoding quantum communication protocols involving pure states of multiple qubits, unitary transformations, and projective measurements into another set of protocols that employ coherent states of light in a superposition of optical modes, linear optics transformations and measurements with single-photon threshold detectors. This provides a general framework for transforming protocols in quantum communication into a form in which they can be implemented with current technology. We explore the similarity between properties of the original qubit protocols and the coherent-state protocols obtained from the mapping and make use of the mapping to construct new protocols in the context of quantum communication complexity and quantum digital signatures. Our results have the potential of bringing a wide class of quantum communication protocols closer to their experimental demonstration.