The Dicke model extended to two bosons of different frequencies or equivalent generalized Jahn-Teller lattice model are shown to exhibit a spontaneous quantum phase transition between the polaron-modified "quasi-normal" and squeezed "radiation" phase with the transition point dependent on the frequencies. In a finite lattice a mixed domain of coexistence of the quasi-normal and modified radiation phase is created within the quasi-normal phase domain. There occurs a field-directed oscillation-assisted tunneling (hopping). The field is driven by simultaneous squeezing and polaron-dressing of the collective boson level mode due to the additional boson mode. In a finite lattice in the radiation domain there occurs a sequence of local tunnelings (oscillations) between two minima of a local potential weakly coupled to two assisting oscillations. The "radiation" phase reveals itself as an almost ideal instanton--anti-instanton gas phase. The correlations among the energy levels mediated by the additional mode in the mixed domain considerably reduce the level repulsions. As a consequence, the Wigner level spacing probability distribution of the two-boson Dicke model is non-universally reduced from the Wigner to the semi-Poisson and asymptotically to the Poisson distribution of level spacings. The correlations cause a suppression of the coherence of the radiation phase as finite-size effect. Possible applications of the present theory are suggested.
详细资料
关键词: cond-mat.quant-gas
文献种类: Journal Article
备注:arXiv:0912.3273v1; 33 pages, 7 Figures, in progress in Phys.Rev.B
作 者
学科领域 自然科学 » 物理学
High-Power Collective Charging of a Solid-State Quantum Battery
浙公网安备 33010202000686号 ( 浙ICP备09035230号-1 )
