講演情報
[8a-E208-6]マグノン熱ゆらぎのスクイージングと熱エンタングルメントの生成
〇日置 友智1,2,3、東條 開斗1、Elyasi Mehrdad2、堀部 聡平1、清水 祐樹1、星 幸治郎1,4、巻内 崇彦3、E. W. Bauer Gerrit2、齊藤 英治1,2,3,4 (1.東大工、2.東北大AIMR、3.理研CEMS、4.東大BAI)
キーワード：
マグノン、スクイーズ、ゆらぎ
Squeezing is the redistribution of fluctuations between two conjugate variables, reducing noise in one quadrature while increasing it in the other. Quantum squeezing, which suppresses vacuum fluctuations, is essential for gravitational-wave detection and quantum entanglement generation. Thermal squeezing applies the same idea to thermal fluctuations, offering enhanced sensitivity and access to engineered nonequilibrium states. In this study, we realized thermal magnon squeezing in a magnetic thin film and generated correlations between magnetization dynamics localized at different surfaces. We used parametric excitation, where a microwave magnetic field at twice the ferromagnetic resonance frequency creates two magnons from one microwave photon. In the non-degenerate case, two magnons with different frequencies are generated when their frequency sum matches the excitation frequency, producing correlations between them. The sample was a 1.4-µm-thick Y3Fe5O12 (YIG) disk coated with platinum. Asymmetric electromagnetic boundary conditions break spatial inversion symmetry and make surface modes on the top and bottom surfaces have different frequencies. By tuning the external magnetic field, we achieved non-degenerate excitation of these surface-localized magnons, demonstrating magnon squeezing and correlated magnetic dynamics.