标题： 室温玻色-爱因斯坦磁子凝聚体中的超电流 显示英文标题

标题： Supercurrent in a room temperature Bose-Einstein magnon condensate

摘要： 我们报告了在室温下制备的钇铁石榴石磁膜中存在磁子超流的证据，并且该磁子玻色-爱因斯坦凝聚体受到热梯度的影响。磁子凝聚体是在参数激发的磁子气体中形成的，其时间、频率和波矢分辨的布里渊光散射谱学用于研究其时间演化。发现探测激光束焦点处的局部加热会增强泵浦脉冲终止后自由演化的磁子凝聚体密度的时间减少，但不会改变气态磁子相的弛豫动力学。这种现象被理解为由于凝聚体波函数中的温度和因此产生的磁化率梯度引起的相位梯度，在凝聚体内出现了磁子超流。 显示英文摘要

摘要： We report evidence for the existence of a supercurrent of magnons in a magnon Bose-Einstein condensate prepared in a room temperature yttrium-iron-garnet magnetic film and subject to a thermal gradient. The magnon condensate is formed in a parametrically populated magnon gas, and its temporal evolution is studied by time-, frequency- and wavector-resolved Brillouin light scattering spectroscopy. It has been found that local heating in the focal point of a probing laser beam enhances the temporal decrease in the density of the freely evolving magnon condensate after the termination of the pumping pulse, but it does not alter the relaxation dynamics of the gaseous magnon phase. This phenomenon is understood as the appearance of a magnon supercurrent within the condensate due to a temperature- and, consequently, magnetisation-gradient induced phase gradient in the condensate wave function.