Scalable quantum technologies on optical cluster states

Thursday 20 Apr 23


Ulrik Lund Andersen
DTU Physics
+45 45 25 33 06


Jonas Schou Neergaard-Nielsen
Associate Professor
DTU Physics
+45 61 77 45 38
Quantum computers are developing at a pace faster than deemed possible just a decade ago, but scalability remains an issue. DTU Physics leads new EU Horizon Europe effort on unfolding the potential of optical cluster states for scalable quantum technologies.

A broad consortium of academic and industrial partners will the next 4 years advance the development of scalable quantum technologies based on optical cluster states. The technology is drawing the attention of more and more stakeholdersrecognising its potential. 

However, scalability remains a core challenge that must be addressed successfully before quantum computers can deliver on the promised speed-up of hard high-impact computational problems. 

Photonic quantum computing offers a promising route towards scalability, and this is the core motivation for the project “Scalable Continuous Variable Cluster State Quantum Technologies (CLUSTEC)” which has recently received funding from the highly competitive Horizon Europe programme. It will be coordinated by researchers at DTU Physics. 

Quantum computing on entangled clusters 

Optical cluster states as a resource towards scalability is the key concept that the new consortium will explore and develop. It is a particular type of complex macroscopic and highly entangled quantum states in which 10,000s of spatiotemporal modes of light are combined in one intricately interconnected structure, forming the canvas for a quantum computer. 

“Information can be encoded into one end of the cluster. And by leveraging the quantum entanglement it can be processed and teleported through the cluster using carefully orchestrated measurements, realising a quantum computation,” says professor Ulrik Lund Andersen who is principal investigator of the project. 

Continuous variable cluster states as a framework for quantum computing have gained particular attention in recent years. Not least thanks to the pioneering research conducted at DTU Physics. 
However, the application of cluster states is not limited to quantum computing but can also be exploited for quantum networking protocols. In CLUSTEC, both will be explored, and the full technological potential will be unfolded through conceptual as well as experimental work.

Unique constellation of theoretical and experimental expertise 

Pushing the frontiers on both theoretical and experimental aspects of cluster states is only possible thanks to the diverse range of expertise encompassed in the CLUSTEC consortium. 

Spanning partners from Germany, France, Switzerland, Czech Republic, and Denmark, the project brings together leading researchers in foundational quantum mathematics, quantum information science, quantum algorithms, and experimental quantum optics and is therefore in a unique position to push forward the field. 

“I am very pleased that the various research environments in Europe within quantum technology are starting to work more and more across the classical research disciplines. There is huge potential here,” says professor Jørgen Ellegaard Andersen from Center for Quantum Mathematics at University of Southern Denmark, who is also a CLUSTEC partner.

Scaling up and down

In addition to the strong academic participation, CLUSTEC includes industrial expertise on integrated photonics from Swiss CSEM and German quantum technology start-up Q.Ant GmbH. One of the aims of CLUSTEC is to develop an integrated photonic system for scalable generation of cluster states based on lithium niobate. Project leader, associate professor Jonas Schou Neergaard-Nielsen from DTU Physics adds: 

”We have already demonstrated continuous variable cluster states in a bulk optics and fibre system, but for the technology to become practically viable it must be transformed onto an integrated photonic platform. We believe the lithium niobate platform is the strongest candidate for this.”

Consequently, it is no coincidence that CLUSTEC has CSEM as a partner as the Swiss RTO contributes market-leading microfabrication expertise on exactly that material platform. This know-how will be essential for realising chip-scale devices. 

“It is exciting for us to coordinate a research project with such a high degree of interdisciplinarity and I am confident that this is exactly the ingredient that will enable us to go further and make significant progress on demonstrating the potential of continuous variable cluster states for quantum technologies,” Ulrik Lund Andersen concludes.

Further information about CLUSTEC

Scalable Continuous Variable Cluster State Quantum Technologies

EC investment from the Horizon Europe programme: DKK 22.5m

Project duration: 4 years

CLUSTEC partners are:

  • Technical University of Denmark (coordinator)
  • University of Southern Denmark
  • Johannes Gutenberg-Universität Mainz
  • Heidelberg University
  • Palacky University Olomouc
  • The French National Centre for Scientific Research (CNRS)
  • Swiss Center for Electronics and Microtechnology (CSEM)
  • Q.Ant GmbH

News and filters

Get updated on news that match your filter.