Large-scale multipartite entanglement on a quantum metrology network

Introduction

Hundreds and thousands of fireflies synchronize their dazzling light in summer nights – one of nature’s most beautiful demonstrations on the importance of synchronization and scalability in a network. So we ask the question, is it possible and even necessary to synchronize all components in a complex large-scale quantum network?

Timeliness of the Question

This is not a question for the future. Rapid experimental progress in recent years has brought first rudimentary quantum networks within reach, highlighting the timeliness and need for unified frameworks. This proposal, MiNet, aims to establish a unified framework on "time", both experimentally and theoretically.

Requirements for Quantum Networks

Similar to a classical network, a future quantum network may have to attach accurate timing stamps to all events that occur, such as the generation and storage of qubits. However, entanglement swapping, which will be used to scalably connect a large ensemble of quantum nodes, puts a stringent requirement on this timing task, making it beyond today’s technologies.

Project Overview

MiNet will build a large-scale multipartite entanglement testbed connecting two science cities in north Germany, Hannover and Braunschweig. Taking advantage of the latest metrology advances, MiNet will use a telecom fiber-based optical clock network to disseminate ultra-stable time/frequency information to devices in three remote laboratories in the two cities.

Scalability Solutions

The important requirement on scalability, on the other hand, will be provided by semiconductor quantum dot sources that have seen incredible improvement recently.

Significance of MiNet

This project is at the forefront of semiconductors, quantum communication, and metrology. MiNet will be the first of its kind, allowing one to gain the full advantages of available resources within a clocked quantum network.

Long-term Vision

In the long term, the fiber-based optical clock network, as part of a Pan-European collaborative effort, may help to synchronize a large number of quantum computing and communication devices at scales that can never be reached before.