SQUARE member Professor Philippe Goldner and his team from Chimie ParisTech, PSL University, CNRS, have demonstrated that nanoscale memories of rare-earth nanoparticles crystals are capable of storing light efficiently, making them promising candidates for developing multimode and long-storage quantum memories.

Fossati et al.: A Frequency-Multiplexed Coherent Electro-optic Memory in Rare Earth Doped Nanoparticles (Nano Letters 2020) https://pubs.acs.org/doi/10.1021/acs.nanolett.0c02200

Thomas Kornher and the team around Roman Kolesov in Jörg Wrachtrup's group at the university of Stuttgart managed to get an important step ahead for rare earth ions: They could sense a single silicon nuclear spin by optically reading out a single Cerium ion. Such nuclear spins are promising as long-lived quantum bits of larger multi-qubit registers. See the article at PRL https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.170402 and the Physics Synopsis https://physics.aps.org/articles/v13/s56.

The SQUARE consortium met for an intense meeting at ICFO, where significant progress was presented and discussed: Highlights include the dynamic control of Purcell enhancement of Erbium ions (https://arxiv.org/abs/2001.08532), sensing of individual nuclear spins with a single rare-earth electron spin, and an extended theory for quantum interactions with pulses of radiation (https://arxiv.org/abs/2003.04573).

The summer school of the Quantum Flagship project SQUARE provided an introduction to quantum computing and quantum networks with a focus on implementations with optically adressable rare earth ion spins, specifically the approaches that are persued within the SQUARE project.
The meeting gathered 37 researchers and students for 2 full days, and all SQUARE partners were present. All SQUARE members were present, and guests from the most related flagship projects OpenSuperQ, AQTION, and QIA, as well as from other groups in the field of REI quantum memories, networks, and materials were present.

Summer School 2019

The SQUARE Flagship project has been presented in the context of quantum research  at the 69 Lindau Nobel Laureate Meeting during a boat trip to the island of Mainau.

The first SQUARE publication is online: Alexander Kiilerich and Klaus Molmer present a formalism for the evolution of quantum states of a light pulse after its interaction with a quantum scatterer - a new tool to describe quantum networks. 

Link to publication

EQTC 2019, the first Quantum Flagship conference 18-22 February 2019, gathered around 400 people from academia, industry, policy makers, funders and educators.

All flagship projects were presented, including SQUARE, and several audience discussions on QT, innovation, governance, education, standardization etc took place.

Link to EQTC 2019

Part of the SQUARE consortium has met at the Rare Earth Ion Worshop in Geneva, with several presentations contributed. Exciting development in the field - Yb:YSO as promising quantum memory, cavity-enhanced single ion readout & control, &much more!

On 29-30 October 2018, the launch of the Quantum Flagship took place in the historical site of the Hofburg in Vienna. The initiative was presented, with networking and technical sessions, to help network the different parties, including researchers from academia and industry, educators and decision makers. SQUARE did participate!

Link to Quantum Flagship Homepage

On Oct. 8.& 9. 2018, the SQUARE consortium assembled for the Kickoff meeting at KIT. The project goals and fist steps were discussed, and networking between members was initiated to launch the interactions for the project.