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Wehner Group

Our goal is realize a large-scale quantum network as part of QuTech’s Quantum Internet Division. We develop new theory, methods and design strategies to overcome the many challenges in realizing this new quantum technology and find useful new quantum software applications for quantum networks. In close collaboration with our European partners in the Quantum Internet Alliance and the experimental groups here at QuTech, we aim to implement new quantum network applications and inspire new theory that can overcome challenges presented by practical implementations.

 

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To achieve these ambitious goals, our team consists of people from both computer science and physics. We work towards:

  • Contribution to and coordination of the European efforts within the Quantum Internet Alliance of bringing Quantum Internet technology steps closer to realization and eventually the market.
  • New or improved software applications and protocols for quantum networks, with a focus on resource efficiency and performance in near-term quantum networks.
  • A blueprint for the future development of a large-scale Quantum Internet factoring in hardware parameters, network architecture and control plane performance, using our purpose-built simulator NetSquid.
  • Design and implementation of a software and network stack for a Quantum Internet, thereby turning quantum networks from ad-hoc physics experiments to a well-defined and robust technology.

Follow the latest developments in our work on twitter via @StephWehner.

Applications

Our research in quantum network applications has three main focus point. First, we develop new quantum network protocols in the domain of cryptography and distributed systems. Examples of recently developed protocols include secure secret key generation among multiple parties, two-party cryptography, anonymous transmission of a quantum message in a network and sharing quantum secrets among a set of parties in a verifiable way. Second, we analyze existing protocols to determine and improve their resource efficiency (number of qubits, Bell pairs, time etc.) and quantum advantage over classical counterparts. Finally, we demonstrate protocols on few-qubit networks and analyze their performance in realistic implementations.

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Blueprint and simulation

We aim to develop a blueprint for the future Quantum Internet, for which we use computer simulations to investigate and optimize over various design aspects of a quantum internet. First, we aim to optimize the type of the hardware that is available at each network node and its required hardware parameters necessary to satisfy end-user demands. Second we analyze the network architecture, including questions like where to place quantum repeaters and what entanglement generation protocols to use for optimal entanglement generation rates. Thirdly, we define the expected performance of the control plane, including a quantum network stack and high-level applications. For this purpose we develop NetSquid, a powerful simulation platform capable of simulating all aspects of quantum networks, ranging from physical hardware to the control plane and high-level applications. This is the main tool we use to simulate large-scale quantum networks. From the simulation results we plan to derive a blueprint for the future Quantum Internet.

Network Stack

We propose a functional allocation of a quantum network stack and construct the first physical and link layer protocols that turn ad-hoc physics experiments producing heralded entanglement between quantum processors into a well-defined and robust service. This lays the groundwork for designing and implementing scalable control and application protocols in platform-independent software. Using our purpose built discrete-event simulator NetSquid for quantum networks, we examine the robustness and performance of our protocol using extensive simulations on a supercomputing cluster.

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