摘要
该文研究了多模各向异性Dicke模型在零温与有限温度下的超辐射相变,应用Laplace方法近似计算了系统的配分函数与Landau势.自由能与序参量经朗道势联系起来,通过对Landau势的全局最小值点的研究,发现该模型同时存在一级量子相变与二级超辐射相变,获得了相边界的解析表达式,该相边界由所有模式的耦合强度共同决定.增加场模的数量将降低每个场模的临界耦合强度,这将使得超辐射相变得更为容易.该结果可以回到单模情况.
The superradiant phase transitions in the multimode anisotropic Dicke model at zero and finite temperature have been studied.We approximately calculate the partition function and the Landau potential by Laplace method.The Landau potential is a bridge between the free energy and the order parameter.By studying the global minimum of the Landau potential,we find the system exhibits both a first-order quantum phase transition and a second-order superradiant phase transition.We also obtain the analytical expression of the phase boundary,which is determined by all the coupling parameters together.And increasing the number of field modes will lower the critical coupling strength,which makes it more accessible to reach the superradiant phase for each mode.Our results can recover the results of the single-mode case.
作者
赵文
唐千
田军龙
彭杰
ZHAO Wen;TANG Qian;TIAN Junlong;PENG Jie(School of Physics and Optoelectronics,Xiangtan University,Xiangtan 411105,China;Gansu Province Qingyang Forestry School,Qingyang 745000,China;Department of Electronic Science,College of Big Data and Information Engineering,Guizhou University,Guiyang 550025,China)
出处
《湘潭大学学报(自然科学版)》
CAS
2024年第6期35-46,共12页
Journal of Xiangtan University(Natural Science Edition)
基金
湖南省自然科学基金(2022JJ30556)。