Nonclassical effects in a highly nonlinear generalized homogeneous Dicke model

Yang Li, Zhao-Xian Yu, Kun Zhao

Ning Yu, Shiran Wang, Chunfang Sun +1 more

In this work, we propose a method to investigate controllable qubit-resonator interactions in a Dicke model with driven biased term. The nonlinearity of the spectrum, which can be induced by qubit-resonator interactions, plays an important role in such controllable interactions. To gain insight into the mechanism of the nonlinearity, we perform a unitary transformation of the Hamiltonian. The results show that the nonlinearity of the transformed Hamiltonian depends on the qubit-resonator coupling strength. The general forms of the effective Hamiltonians are discussed in detail based on the frequency modulation approach. The dynamical evolution can be switched on and off by adjusting the modulation parameters. By utilizing such controllable interactions, we discuss the creation of Dicke states and the arbitrary superposition of Dicke states. We also consider the nonlinearity of the energy level for the limit of large qubit numbers. In the thermodynamics limit, the Kerr type nonlinearity is induced from "magnon"-resonator coupling, and the selective preparation of "magnon" Fock states can be studied under a "magnon" scenario.

Xiaoyong Guo, Zhongzhou Ren, Zimeng Chi

In this paper we investigate a ground state quantum phase transition of nonlinear light in a generalized finite size Dicke model, which includes a Kerr-type nonlinear field term along with the counter-rotating interaction. The numerical solution is presented. We show that, in the ground state, the intracavity photons exhibit a third-order QPT from the bunching to the antibunching quantum phase. This phase transition stems from the competition between the atom-induced coupling and the effective photon–photon interaction. We also demonstrate that the general properties of the phase transition do not qualitatively alter by the size of the atomic ensemble and by the detuning between atoms and light, as well.

Feng Pan, Tao Wang, Jing Pan +2 more

Dávid Nagy, Gábor Kónya, Gergely Szirmai +1 more

We show that the motion of a laser-driven Bose-Einstein condensate in a high-finesse optical cavity realizes the spin-boson Dicke model. The quantum phase transition of the Dicke model from the normal to the superradiant phase corresponds to the self-organization of atoms from the homogeneous into a periodically patterned distribution above a critical driving strength. The fragility of the ground state due to photon measurement induced backaction is calculated.

Yuyu Zhang, Tao Liu, Qing‐Hu Chen +1 more