Quantum magnonics

Quantum magnonics concerns quantum states of magnons and the interplay between magnon spintronics, and quantum information science. It is a highly interdisciplinary field that combines spintronics, quantum optics, and quantum information. In this chapter, we will first introduce magnon quantum states, including magnon antibunching and squeezed states. Macroscopic quantum phenomena including spin superfluidity and Bose–Einstein condensation will also be briefly covered. Hereafter, we discuss the integration of magnonic systems with mature quantum platforms, including photonic cavities, qubits, and phononic systems, together with the applications of hybrid magnonic systems. Finally, we present an outlook on the opportunities and challenges for quantum magnonics.