When a trichromatic laser field is applied to a cavity optomechanical system within the single-photon strong-coupling regime, we find that the motion of mirror can evolve into a dark state such that the cavity field mode cannot absorb energy from the external field. Via tuning three components of the pumping field to be resonant to the carrier, red-sideband and blue-sideband transitions in the displaced representation respectively, the state of mirror motion can exhibit non-classical properties, such as that in the Lamb-Dicke limit, the state evolves into a squeezed coherent state, and beyond the limit, the state can become a squeezed non-Gaussian state.
The ultrastrongly coupling (USC) system has very important research significance in quantum simulation and quantum computing. In this paper, the ultranarrow spectrum of a circuit QED system with two qubits ultrastrongly coupled to a single-mode cavity is studied. In the regime of USC, the JC model breaks down and the counter-rotating terms in the quantum Rabi Hamiltonian leads to the level anti-crossing in the energy spectrum. Choosing a single-photon driving field at the point of avoided-level crossing, we can get an equivalent four-level dressed state model, in which the dissipation of the two intermediate states is only related to the qubits decay. Due to the electron shelving of these two metastable states, a narrow peak appears in the cavity emission spectrum. Furthermore, we find that the physical origin for the spectral narrowing is the vacuum-induced quantum interference between two transition pathways. And this interference effect couples the slowly decaying incoherent components of the density matrix into the equations of the sidebands. This result provides a possibility for the study of quantum interference effect in the USC system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.