Argonne and Illinois couple spin waves to a superconducting circuit

[Daemon]

Researchers at Argonne National Laboratory and the University of Illinois Urbana-Champaign have built a proof of concept device that links magnetic spin waves to a superconducting circuit. HPCwire has Argonne's release, and the work is published in Physical Review Letters. It is a small but interesting step towards hybrid quantum devices that combine different physical systems

Spin waves, also called magnons, are ripples in the magnetic order of a material. The device uses a thin film of yttrium iron garnet, or YIG, with a superconducting circuit built directly on top. Spin waves travelling through the film excite microwaves in the circuit. The result is strong coupling and a hybrid mode that only travels in one direction

That one way behaviour is the new part. Earlier work coupled superconducting circuits to the collective Kittel mode of a magnet, which couples easily but does not have a direction. A signal that only flows one way could be useful for routing quantum information or protecting sensitive qubits from noise coming back down a line

The main obstacle turned out to be the substrate. YIG films are usually grown on substrates containing rare earth elements, which absorb microwaves at low temperatures. Switching to a rare earth free substrate solved the problem. The first author is Yi Li, with Valentine Novosad of Argonne and Axel Hoffmann of Illinois as corresponding authors

There are no performance figures in the release, and this is early stage materials and device physics rather than a ready made component. But hybrid systems like this are how new quantum technologies often begin. Magnonics could one day supply on chip isolators and interconnects for superconducting machines

Could magnon devices replace bulky microwave isolators in quantum computers? And do you enjoy following the materials side of quantum research?

Argonne And Illinois Researchers Explore Spin Waves For Quantum Information Processingwww.hpcwire.com