On polariton instability and thermodynamic phase transition in a photon-matter system
On polariton instability and thermodynamic phase transition in a photon-matter system
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关于光子-物质系统中的极化子不稳定性和热力学相变
DOI：
10.1088/0305-4470/12/9/025
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
M. Yamanoi
中科院分区：
文献类型：
--
作者：
M. Yamanoi
结果表明，在最小耦合哈密顿量与A2项的旋转波近似导致一个不正确的能谱的极化子模式：特别是一个虚假的极化子不稳定性，不应该发生的光子-物质系统组成的辐射和原子没有库仑相互作用。因此，在A2项的存在下，反向旋转项在系统的不稳定性中起着至关重要的作用。在迪凯模型中的超辐射相变被证明是伴随着极化激元不稳定性，因此由光子-物质系统的基态的不稳定性。因此，在研究系统基态的热力学相变和不稳定性时，不应采用旋波近似，也不应忽略A2项。
It is shown that the rotating wave approximation in the minimal coupling Hamiltonian with the A2 term leads to an incorrect energy spectrum of the polariton mode: in particular, to a spurious polariton instability which should not occur for a photon-matter system consisting of radiation and atoms without the Coulomb interaction. Thus the counter-rotating term in the presence of the A2 term plays a crucial role in the instability property of the system. The super-radiant phase transition in the Dicke model is shown to be accompanied by polariton instability, and therefore by instability of the ground state of the photon-matter system. The rotating wave approximation, as well as the neglect of the A2 term, should therefore not be made for the study of the thermodynamic phase transition and instability properties of the ground state of the system.