Dicke模型的相变：统一观点
Phase transitions of the Dicke model: a unified perspective
摘要：
Dicke模型表现出多种相变。从正常相到超辐射相的量子相变的标志是参与率的标度发生了戏剧性的变化。我们发现，超辐射相的基态表现出多重分形的参与率标度为整个希尔伯特空间维数的平方根。热相变温度，我们得到了一个精确的解析表达式，是惊人的两个自旋之间的互信息捕获。在超辐射相的激发态量子相变中，我们发现了一个新的上截止能量，下截止能量和上截止能量之间的中心能带表现出明显不同的行为。这一发现得到了几个本征矢量性质的证实：自旋和玻色子之间的冯诺依曼纠缠熵，平均光子数，两个自旋之间的并发，和参与比。从而得到了三种不同类型相变的统一图象。
英文摘要：
The Dicke model exhibits a variety of phase transitions. The quantum phase transition from the normal phase to the super-radiant phase is marked by a dramatic change in the scaling of the participation ratio. We find that the ground state in the super-radiant phase exhibits multifractality manifest in the participation ratio scaling as the square root of the full Hilbert space dimension. The thermal phase transition temperature, for which we obtain an exact analytical expression, is strikingly captured by the mutual information between two spins. In the excited state quantum phase transition within the super-radiant phase, we discover a new upper cut-off energy; the central energy band between the lower and upper cut-off energies shows distinctly different behaviour. This finding is corroborated with the aid of several eigenvector properties: von Neumann entanglement entropy between spins and bosons, the mean photon number, concurrence between two spins, and participation ratio. Thus we obtain a unified picture for the three different kinds of phase transitions.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
