title: Nonlinear coupling between a nitrogen-vacancy-center ensemble and a superconducting qubit.
abstract: By exchange of virtual microwave photon induced by a transmission line resonator, the nonlinear interaction between a nitrogen-vacancy-center ensemble (NVE) and a superconducting charge qubit is achieved in circuit quantum electrodynamics, where the nonlinear coupling results from the second order of the coupling between the magnetic field of the transmission line resonator and the charge qubit. In our case, the nonlinear coupling can be much enhanced by a factor of the total spin number in the NVE. As an application, we present a potentially practical scheme to realize the squeezing of the NVE using the nonlinear coupling, which is within reach of the currently available technology.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Wen
authors.forename: W L
authors.initials: WL
authors.lastname: Yang
authors.forename: M
authors.initials: M
authors.lastname: Feng
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: Du