title: Strong nonlinear coupling between an ultracold atomic ensemble and a nanomechanical oscillator.
abstract: A new type of collective nonlinear coupling is presented via the indirect interaction between an ultracold atomic ensemble and a nanomechanical oscillator. More intriguingly, its interaction strength is enhanced largely with a factor of the atomic number, and thus, reaches a strong coupling regime within current experimental parameters. For the large atomic number, this obtained nonlinear coupling describes the interaction between the phonon and a pair of quasiparticle. Physically, this pair of quasiparticle is excited from the ultracold atomic ensemble when a phonon is emitted and vice versa. Based on these collective excitations, the nonlinear optical processes with the χ(2) term are simulated successfully.
authors.affiliation: State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China. chengang971@163.com
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Yongping
authors.initials: Y
authors.lastname: Zhang
authors.forename: Liantuan
authors.initials: L
authors.lastname: Xiao
authors.forename: J-Q
authors.initials: JQ
authors.lastname: Liang
authors.forename: Suotang
authors.initials: S
authors.lastname: Jia