Transmon qubit as a sensor for quantum characteristics of magnon

Experimental verification of non-classical magnon states is of great importance, which clarifies various buds of quantum magnonics towards quantum technologies. Among others, antiferromagnetic magnons are very intriguing as they possess robust and energy-efficient quantum features [1, 2], and therefore allow sustainable quantum developments. Here we discuss how a photon [3] and particularly a transmon qubit can be used to experimentally observe interesting quantum phenomena such as magnon polarization, squeezing, and entanglement in antiferromagnetic and ferrimagnetic materials.



[1] V. Azimi-Mousolou, et al., Hierarchy of magnon mode entanglement in antiferromagnets, Phys. Rev. B 102, 224418 (2020).

[2] Y. Liu, et al., Tunable and robust room-temperature magnon-magnon entanglement,

arXiv:2209.01032 (2022).

[3] V. Azimi-Mousolou, et al., Magnon-magnon entanglement and its detection in a microwave cavity, Phys. Rev. Applied (2021).