The results of the SQUARE project will contribute to strengthen the European high-tech industry as it aims to establish a new platform for quantum computing, quantum networking and quantum communication.


Project Progress & Achievements: May 2020

Researchers' summary

Within the first funding period, the SQUARE project has worked towards the detection and control of single rare earth ions as optically addressable spin qubits, developed several device elements required for scalable quantum nodes, and devised theoretical frameworks to describe e.g. optically interconnected quantum nodes.

Specifically, they were able to demonstrate the detection and quantum control of a single Cerium spin and used it to sense nearby Silicon nuclear spins as possible quantum memories. Furthermore, they demonstrated dynamic tuning of strong Purcell enhancement of Erbium ion emission, which is a crucial ingredient for efficient single ion readout, optimized quantum gates, and interconnection of quantum nodes. 

Another important breakthrough was the development of a theoretical framework to realistically describe travelling quantum pulses, which is key to understand the features and limitations of quantum networks and the interconnection of quantum nodes. Also, realistic modelling to assess the limits of single qubit gate fidelities was performed.

Another focus was on the technology development of scalable device elements for a rare-earth ion quantum computer, including a cryogenic nanopositioning platform, fiber cavities, rareearth-ion-doped thin films, a scheme for a scalable laser source that can coherently address up to 100 qubits, and a concept for an all-European closedcycle cryo-cooler.

More Information

Find more information about what SQUARE achieved here

To mark the mid-point of the Quantum Technologies Flagship’s eighteen-month ramp-up phase in May 2020, a mid-term review was published with information about the achievements of all the projects. Read it here.