Professor Yasunobu Nakamura and his colleagues have succeeded in quantitatively observing magnons, the quantum behavior of magnets, for the first time. Using a qubit device on a superconducting circuit as an ultra-sensitive detector, they counted the number of magnons excited in a ferromagnetic single crystal one by one and clarified their distribution. This result shows that superconducting qubit devices can be used as a new sensor application for quantum behaviors.
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