Single- and two-mode magnon thermal squeezing

Squeezed states play a central role in modern precision measurement and information processing, reducing the noise through manipulating its distributions in phase space. Although squeezing has been explored in various physical systems, realization and characterization in magnetic media remain largely unexplored. Here we demonstrate the single-mode thermal squeezing of the magnetization dynamics in an yttrium iron garnet film using microwave parametric excitation. We also demonstrate two-mode thermal squeezing in the form of correlated fluctuations of magnons concentrated on the top and bottom surfaces of the film. Establishing the control of thermal squeezing in magnetic systems provides insights into the fluctuation dynamics of the magnetic order, and represents a key advance in the quest to observe quantum effects in magnetic films. Obtaining squeezed states in magnets are a key challenge for future spin-based sensing and information technology. Now thermal squeezing of magnons, where noise drops below thermal levels, is shown in a ferrimagnetic insulator device.