Simultaneous multiple-users quantum communication across a spin chain channel

TL;DR

This paper introduces a protocol enabling multiple users to simultaneously share a quantum spin chain channel with high fidelity and no crosstalk, significantly improving quantum communication networks.

Contribution

It presents a novel method for multi-user quantum communication over spin chains by tuning Hamiltonian parameters to prevent crosstalk, adaptable to various physical platforms.

Findings

High transmission fidelities achieved

No crosstalk between users demonstrated

Feasible implementation on superconducting quantum simulators

Abstract

The time evolution of spin chains has been extensively studied for transferring quantum states between different registers of a quantum computer. Nonetheless, in most of these protocols only one pair of sender-receivers can share the channel at each time. This significantly limits the rate of communication in a network of many users as they can only communicate through their common data-bus sequentially and not all at the same time. Here, we propose a protocol in which multiple users can share a spin chain channel simultaneously without having crosstalk between different parties. This is achieved by properly tuning the local parameters of the Hamiltonian to mediate an effective interaction between each pair of users via a distinct set of energy eigenstates of the system. We introduce three strategies with different levels of Hamiltonian tuning, each might be suitable for a different physical platform. All the three strategies provide very high transmission fidelities with vanishingly small crosstalks. We specifically show that our protocol can be experimentally realized on currently available superconducting quantum simulators.