CAREER: Fundamental phenomena in magnon condensates

非技术摘要：玻色子是整数自旋的粒子，允许玻色-爱因斯坦凝聚（BEC）的基本量子效应，表现为在其他非相干多粒子系统中自发形成宏观相干量子态。该项目将提高对磁准粒子-磁振子中BEC现象的理解。这项工作可能对量子信息科学、固态物理和现代磁学领域产生变革性影响，并有助于保持美国在量子信息科学和技术领域的领导地位。这个CAREER项目探索铁磁结构，以了解磁振子BEC特性以及与其旁边存在的致密磁振子气体的相互作用，使用最先进的纳米纤维，光学和微波表征技术。该项目的教育部分将当代研究主题整合到现有的研究生和本科生课程中，创建新的量子物理和量子信息科学实验室课程，为广泛的社区提供科学发展的机会，并通过组织科学比赛增加STEM学生的数量。技术摘要：尽管在磁振子气体和凝聚体领域取得了许多成就，如磁振子超电流的观测，博戈留波，约瑟夫森效应和第二声音，还有许多有趣的基本问题仍然悬而未决。其中之一是这些现象如何受到边界或几何约束的影响，以及在铁磁材料中支持磁振子BEC的系统的临界尺寸是多少。该项目将最先进的微纳米结构与光学布里渊散射光谱相结合，并在室温和低温下引入光学加热技术。该项目的目标是：㈠实验观察和比较常规三维、准二维和准一维结构中的磁振子BEC动力学; ㈡建立持久凝聚相并确定其存在区域; ㈡研究具有周期性边界条件的系统（环）中磁振子BEC的特性; ㈢建立连续和封闭样品中磁振子第二声波和Bogoliubov波的完整联合模型;（4）实验观察和研究磁振子热力学激光效应。该项目支持本科生和研究生在先进的光谱技术，低温和纳米纤维的培训。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Non-technical abstract:Bosons are particles of integer spin that allow for the fundamental quantum effect of Bose-Einstein Condensation (BEC), which manifests as the spontaneous formation of a macroscopic coherent quantum state in an otherwise incoherent multi-particle system. The project will improve understanding of the BEC phenomenon in magnetic quasiparticles – magnons. This work may have a transformative effect on the fields of quantum information science, solid-state physics, and modern magnetism, as well as help maintain US leadership in the area of quantum information science and technology. This CAREER project explores ferromagnetic structures to understand magnon BEC properties and interactions with a dense magnon gas existing alongside it using state-of-the-art nanofabrication, optical, and microwave characterization techniques. The educational component of the project integrates contemporary research themes into existing graduate and undergraduate courses, creates new quantum physics and quantum information science lab courses, provides access to scientific developments to a broad community, and increases the number of students in STEM through the organization of scientific tournaments.Technical abstract:Despite many achievements in the field of magnon gases and condensates, like the observation of magnon supercurrents, Bogoliubov waves, Josephson effect, and second sound, there are many intriguing fundamental questions still open. One of them is how these phenomena are affected by boundaries or geometrical confinement, and what are the critical sizes of the system to support magnon BEC in ferromagnetic materials. The project combines state-of-the-art micro- and nano-structuring with optical Brillouin light scattering spectroscopy and introduces optical heating techniques at room as well as cryogenic temperatures. The project's aims are: (i) Experimentally observe and compare magnon BEC dynamics in conventional 3D, quasi-2D, and quasi-1D structures; (ii) Create a persistent condensed phase and determine its areas of existence; (ii) Study properties of magnon BEC in systems with periodic boundary conditions (rings); (iii) Create a complete joint model of magnon second sound and Bogoliubov waves in continuous and confined samples; (iv) Experimental observe and study magnon thermodynamic lasing effect. The project supports the training of undergraduate and graduate students in advanced optical spectroscopy techniques, cryogenics, and nanofabrication.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.