Dissipative quantum phase transition in a biased Tavis

Dissipative quantum phase transition in a biased Tavis–Cummings model

Chen Zhen^{1, 2}, Qiu Yueyin³, Zhang Guo-Qiang^{2, †}, You Jian-Qiang^{2, ‡}

(a) Schematic illustration of our proposal for improving the QPT in a hybrid system consisting of a driven ensemble of dissipative NV centers (blue oval) coupled to an active WGM cavity with gain modeled as an auxiliary spin ensemble with population inversion (yellow oval). The input and output fields of the cavity are denoted as ap(in) and ap(out) , respectively. (b) Energy-level diagram for the Hamiltonian in Eq. (16).