The proposed project will experimentally interface ferromagnets with superconducting quantum circuits to study dynamics within the magnet. To this end, magnonic elements made up by thin, structured magnetic films will be strongly coupled to the qubit. Exploring spin-wave dynamics in thin films by coupling to a superconducting qubit complements conventional measurement techniques based on photon, electron or neutron scattering methods, which require highly populated excitations. The project connects to and extends research objects of ground-breaking nature to open up new horizons for quantum, magnon and spin electronics. Magnetic material physics is enhanced by new research concepts such as quantum resolved spectroscopy and coherence measurements on intrinsic dynamic states.
Overall objectives are: i) Ferromagnetic resonator coupled to transmission line: Spin wave resonance at few magnon levels, ii) Noise spectrum analysis of ferromagnet: Spectroscopy of spin processes, iii) Ferromagnetic resonator coupled to qubit: Creation and detection of single magnons, iv) Magnetic noise spectroscopy with qubit: Probing low- and high-frequency
Ultimately, this research addresses new paradigms of quantum nanoelectronics for the benefit of society.
A set of experiments on ferromagnetic excitations down to the quantum regime have been done, and published, as well as studies on the qubit as the sensor. During the project runtime, it became obvious that the engineering of the strong interaction (coupling) between resonators and spin systems is of major scientific interest and reaches beyond the initial project objectives. We have investigated this closer, and published in a set of papers
