Quantum Phase Transitions and Entanglement in the Detuned Dicke Model

Li-Tuo Shen, Xuan-Tong Pei, Zhi‐Cheng Shi +1 more

Camilo A. Estrada Guerra, Jorge Mahecha-Gómez, Jorge G. Hirsch

Ru-Fen Liu, Chia-Chu Chen

The quantum phase transition of mono-mode Dicke models with two atoms is discussed and analytical results are presented. For arbitrary detuning, the exact spectrum and the concurrence of entanglement are calculated for the two-atoms system. It is shown that sequential quantum phase transitions occur in this system. Evidences have been found to support that quantum phase transition and concurrence are uncorrelated in this particular model. Furthermore, the results of quantum phase transition with extra mode are also discussed.

Michal Kloc, Pavel Stránský, Pavel Cejnar

Isabel Sainz, A. B. Klimov, Luis Roa

Yixiao Huang, Ning-Ju Hui, Wanfang Liu +2 more

Abstract We study the spin-field and the spin-spin entanglement in the ground state of a spin-orbit coupled Bose–Einstein condensate. It is found that the spin-field and the spin-spin entanglement can be induced by the spin-orbit coupling. By mapping the system to the Dicke-like model, the system exhibits a quantum phase transition from a normal (spin balanced) phase to superradiant (spin polarized) phase. The Dicke-like phase transition can be captured by the spin-field and the spin-spin entanglement arising from the spin-orbit coupling. The spin-field and the spin-spin entanglement increase as the Raman coupling increases in the superradiant phase, while they decrease with the Raman coupling increasing in the normal phase. We also consider the effect of a finite detuning on these entanglement show that the presence of the detuning suppresses the spin-field and the spin-spin entanglement.