Exploiting the analogy between ultracold atomic gases and the system of triplons, we study magneto-thermodynamic properties of dimerized quantum magnets in the framework of Bose–Einstein condensation (BEC). Particularly, introducing the inversion (or Joule–Thomson) temperature TJT as the point where Joule–Thomson coefficient of an isenthalpic process changes its sign, we show that for a simple paramagnet, this temperature is infinite, while for three-dimensional (3D) dimerized quantum magnets it is finite and always larger than the critical temperature Tc of BEC. Below the inversion temperature T < TJT, the system of triplons may be in a liquid phase, which undergoes a transition into a superfluid phase at T ≤ Tc < TJT. The dependence of the inversion temperature on the external magnetic field TJT(H) has been calculated for quantum magnets of TlCuCl₃ and Sr₃Cr₂O₈.

中文翻译：

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二聚化量子磁体三重系统的特征温度

利用超冷原子气体与三子系统之间的类比，我们在玻色-爱因斯坦凝聚 (BEC) 框架下研究了二聚化量子磁体的磁热力学性质。特别是，引入反转（或焦耳-汤姆逊）温度吨捷通作为等焓过程的焦耳 - 汤姆逊系数改变其符号的点，我们表明对于简单的顺磁体，该温度是无限的，而对于三维（3D）二聚化量子磁体，它是有限的并且总是大于临界温度吨CBEC 的。低于反转温度吨 < 吨捷通, 三重子系统可能处于液相中, 在吨 ≤ 吨C < 吨捷通. 反转温度对外部磁场的依赖性吨捷通(H)已经计算了 TlCuCl ₃和 Sr ₃ Cr ₂ O ₈的量子磁体。