Description
Insulating magnets hold great promise for quantum technology due to the long lifetime of magnetic excitations and easy interoperability with other systems. Due to the large number of spins in a magnet, they couple strongly to photons confined in a cavity, making magnetic cavities a useful tool to study the quantum behavior of magnets. Among these is the generation of single magnons or photons, offering control at the single quantum level of principal importance for quantum information technology. High-quality single photons from other sources have already been used as a platform for quantum computation.
In this talk I will present our recent theoretical works on magnon and photon blockades in magnetic cavities, including both ferromagnets and antiferromagnets. In the first work [1] we consider photon blockade in cavities with ultra-strong magnon-photon coupling, which we connect to photon quadrature squeezing that reduce the uncertainty when pumping along specific directions. In the second work [2] we instead consider a nanosized antiferromagnet supporting degenerate magnon-modes. The antiferromagnetic ground-state is known to exhibit strong two-mode squeezing, an attractive quality for quantum information technology. The squeezing also causes a highly non-uniform level spacing that can suppress the excitation of multiple bosons leading to both magnon and photon blockade.
[1] V. Falch, A. Brataas, A. Qaiumzadeh, Phys. Rev. B 111, 104425 (2025)
[2] V. Falch, A. Brataas, A. Qaiumzadeh, arXiv:2504.08562
