Quantum Dense Coding Network using Multimode Squeezed States of Light

TL;DR

This paper introduces a scalable multimode quantum dense coding network using continuous variable systems, demonstrating quantum advantage with fixed energy constraints and potential for laboratory implementation.

Contribution

It develops a framework for a multimode dense coding protocol with multiple senders and a single receiver, including capacity calculations and demonstration of quantum advantage.

Findings

Quantum advantage increases with transmitted energy.

Closed-form capacity expressions for two and three senders.

Protocol is scalable and feasible with current laboratory resources.

Abstract

We present a framework of a multimode dense coding network with multiple senders and a single receiver using continuous variable systems. The protocol is scalable to arbitrary numbers of modes with the encoding being displacements while the decoding involves homodyne measurements of the modes after they are combined in a pairwise manner by a sequence of beam splitters, thereby exhibiting its potentiality to implement in laboratories with currently available resources. We compute the closed form expression of the dense coding capacity for the cases of two and three senders that involve sharing of three- and four-mode states respectively. The dense coding capacity is calculated with the constraint of fixed average energy transmission when the modes of the sender are transferred to the receiver after the encoding operation. In both the cases, we demonstrate the quantum advantage of the protocol using paradigmatic classes of three- and four-mode states. The quantum advantage increases with the increase in the amount of energy that is allowed to be transmitted from the senders to the receiver.