Self-Trapping of Magnon Bose-Einstein Condensates in the Ground State and on Excited Levels: From Harmonic to Box Confinement
Self-Trapping of Magnon Bose-Einstein Condensates in the Ground State and on Excited Levels: From Harmonic to Box Confinement
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DOI：
10.1103/physrevlett.108.145303
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发表时间：
2012-04-03
影响因子：
8.6
通讯作者：
Volovik, G. E.
中科院分区：
文献类型：
--
作者：
Autti, S.;Bunkov, Yu. M.;Volovik, G. E.
在0.2T(C)附近的低温下，He-3-B的长寿命相干自旋进动是自旋波激发或磁子在磁陷阱中的玻色-爱因斯坦凝聚的表现，该陷阱是由序参数织构形成的，可以在实验上操纵。随着磁子数目的增加，在自旋-轨道相互作用的影响下，轨道织构发生了重新定向，陷阱的轮廓逐渐由简谐变为方形势垒，壁对磁子几乎无法穿透。这是玻色凝聚在盒子中的第一个实验例子。通过选择性的射频泵浦，陷阱可以填充基态凝聚体或任何激发能级的凝聚体。在后一种情况下，基态同时被来自激发能级的弛豫填充，形成一个由两个共存的凝聚体组成的系统。
Long-lived coherent spin precession of He-3-B at low temperatures around 0.2T(c) is a manifestation of Bose-Einstein condensation of spin-wave excitations or magnons in a magnetic trap which is formed by the order-parameter texture and can be manipulated experimentally. When the number of magnons increases, the orbital texture reorients under the influence of the spin-orbit interaction and the profile of the trap gradually changes from harmonic to a square well, with walls almost impenetrable to magnons. This is the first experimental example of Bose condensation in a box. By selective rf pumping the trap can be populated with a ground-state condensate or one at any of the excited energy levels. In the latter case the ground state is simultaneously populated by relaxation from the exited level, forming a system of two coexisting condensates.