Squeezing Thermal Fluctuations in Magnets: First observation of single- and two-mode thermal squeezing opens pathways to low-noise sensing and next-generation thermal machines

Scientists have long sought ways to control the tiny fluctuations that are always present in physical systems. One powerful approach is “squeezing,” in which fluctuations in one component are reduced while those in another are enhanced. In the quantum realm, squeezed states have enabled ultrasensitive measurements, including gravitational-wave detection, and form a key resource for quantum communication and teleportation. A related concept, thermal squeezing, reduces fluctuations below their ordinary thermal level and is attracting attention as a way to reshape heat flow, enhance work extraction, and reduce the energy cost of information processing.

In this research, the team brings thermal squeezing into magnetism. They demonstrate thermal squeezing of magnons—the collective waves of spins in a magnetic material—in yttrium iron garnet, a widely used magnetic insulator. The researchers observe both single-mode squeezing, where magnetic noise at a single frequency falls below its thermal level and two-mode squeezing, where magnetization fluctuations on opposite sides of the film become correlated over a macroscopic distance. These findings establish a new way to control magnetic noise and open a path toward compact, energy-efficient magnetic and quantum technologies.

Papers

Journal: Nature Physics

Title: Single- and two-mode thermal magnon squeezing

Authors: Tomosato Hioki^*, Kaito Tojo^*, Mehrdad Elyasi, Sohei Horibe, Hiroki Shimizu, Koujiro Hoshi, Takahiko Makiuchi, Gerrit E. W. Bauer and Eiji Saitoh (^*Equal contribution)