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arXiv · 2411.18512

Second-order correlation and squeezing of photons in cavities with ultrastrong magnon-photon interactions

Vemund Falch·Arne Brataas·Alireza Qaiumzadeh
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Abstract

We investigate the second-order photon correlation function in cavity-magnon systems, focusing on ferromagnetic and antiferromagnetic cavities within the ultrastrong coupling regime, and extending beyond the rotating-wave approximation. By deriving exact integral solutions for the second-order correlation function, we demonstrate that counter-rotating magnon-photon interactions induce quadrature squeezing in the cavity mode. Furthermore, we show that tuning the anisotropic magnon-cavity couplings enhances the squeezing effect by changing the level repulsion of the magnon-cavity photon hybrid mode without increasing the cavity photon occupation number. Our study reveals distinct quantum correlation behaviors in ferromagnetic and antiferromagnetic cavities: For ferromagnetic cavities, we show that squeezing increases with coupling strength asymmetry, whereas in the antiferromagnetic case, magnon modes with opposite chirality suppress quantum effects and impose a lower bound on correlation functions. These findings provide a pathway to optimize photon blockade for quantum information technology in magnon-cavity systems in the ultrastrong coupling limit.

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Vemund Falch, Arne Brataas, Alireza Qaiumzadeh. 2024-11-27. Second-order correlation and squeezing of photons in cavities with ultrastrong magnon-photon interactions. https://doi.org/10.1103/physrevb.111.104425

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