Remotely Preparing Many Qubits with a Single Photon

TL;DR

This paper demonstrates how a single photon in a superposition of multiple modes can remotely prepare multiple qubits efficiently, surpassing existing protocols in speed and fidelity.

Contribution

It introduces a reflection-based RSP protocol leveraging photon mode superpositions to prepare multiple qubits simultaneously with reduced phase stabilization requirements.

Findings

Achieves high success rates for multi-qubit RSP with only one photon transmitted.

Provides performance comparable to best existing schemes for single qubit RSP.

Enables preparation of many qubits simultaneously, overcoming qubit lifetime limitations.

Abstract

A single photon in a superposition of $d$ modes naturally encode a $d$-dimensional quantum system, a so-called qudit. We show that such superpositions can be leveraged to achieve a quantum speed-up of remote remote state preparation (RSP): a primitive for several quantum network protocols. For a superposition over $d\geq 2$ modes, the photon state can encode up to ${\rm Log}_2(d)$ qubits, which we exploit in a proposed reflection based RSP protocol with multiple variations. For single qubit RSP, we achieve a performance comparable to the best known existing schemes but with reduced requirements for phase stabilization. For many qubit RSP the achievable success rates remain high despite needing exponentially many temporal modes, since only one photon needs to be transmitted and detected to prepare multiple qubits. By simultaneously preparing many qubits at once, we bypass limited qubit lifetimes limited qubit lifetimes and improve fidelities beyond what is achievable with existing RSP protocols.