Projects as part of the Quantum Transitional Call Participation by SNI members The second half of 2023 saw the launch of four quantum research projects with the participation of SNI members. These projects had been announced as part of the Quantum Transitional Call by the Swiss National Science Foundation (SNSF). For researchers from the Department of Physics at the University of Basel, the support will allow them to continue with their various lines of research, which were previously part-supported by EU funding programs. Although the funding is no substitute for participation in the European programs, it goes some way toward mitigating the impact of exclusion for Swiss research groups. On the road to quantum networks Quantum dots and atomic vapor cells Numerous research groups worldwide are investigating Richard Warburton’s group has already shown that semi- quantum networks with a view to the wide-ranging appli- conductor quantum dots can emit single photons at a high cations they promise, such as the interlinking of quantum rate and with excellent spectral purity. In the SQnet proj- computers or quantum sensors, secure quantum commu- ect launched in September 2023, the researchers will now nication, or the investigation of many-particle systems. use novel quantum dots that emit photons of a speci昀椀c The construction of complex quantum networks, how- wavelength that is compatible with rubidium atoms. For ever, represents a major technological challenge that is the quantum memory, the researchers are using atomic yet to be overcome. vapor cells developed by the Treutlein team. “These are glass bulbs 昀椀lled with rubidium gas that, unlike other Combined expertise quantum memories, also work at room temperature and A powerful platform for such quantum networks is don’t need to be intensely cooled in a cryostat. This is vital being developed by researchers led by Basel professors when it comes to upscaling the technology for a complex Philipp Treutlein and Richard Warburton together with network,” explains Treutlein. colleagues from the Swiss Center for Electronics and Mi- crotechnology (CSEM) in Neuchâtel. The researchers have already performed a proof-of-prin- ciple demonstration with a quantum memory, but they The researchers are using a platform that appears to o昀昀er will need to miniaturize the technology in order to build feasible upscaling from a technological perspective. For a more complex network. The glass cylinders used so each node point in the network, the platform allows re- far are a few centimeters in size and are individually searchers to combine a source of single photons, which produced by a glassblower. Thanks to the expertise of transport information, with a single-photon memory. CSEM colleagues in miniaturization, nanofabrication and The photons are placed in a quantum mechanical super- nanophotonics, it will be possible to produce quantum position state, with one part being stored in the memory memories of a signi昀椀cantly smaller size and to automate while the other part relays quantum information to the the production process. next node points, in order to generate entanglement within the network. Background information Within the international research program known as the announcement of the Quantum Transitional Call Horizon Europe, Switzerland is currently classed as a in 2022 with a view to allowing researchers involved non-associated third country, meaning that researchers in quantum research programs under Horizon Europe from Swiss research institutions have been excluded to continue pursuing their research projects. Five SNI from many EU research programs. Switzerland’s State members from the Department of Physics at the Uni- Secretariat for Education, Research and Innovation has versity of Basel are involved in successful projects that therefore mandated the Swiss National Science Foun- began in the second half of 2023 and are set to receive dation to develop a transitional solution, leading to funding over a period of four years. SNI INSight December 2023 17