First-Order Quantum Phase Transition for Dicke Model Induced by Atom-Atom Interaction

Zhao Xiu-Qin^{1, 2}, Liu Ni^{1, †}, Liang Jiu-Qing¹

(Color online) (a) and (b) as the function of the atom-atom interaction strength for the given collective atom-filed couping strength (the red line), 1.5 (the green line), 1.8 (the violet line).