Exponentially Enhanced Single‐Photon Cross‐Kerr Nonlinearity in Quantum Optomechanics

Abstract

AbstractStrong cross‐Kerr nonlinearity at the single‐photon level is crucial for various quantum applications, but usually very difficult to achieve. In this work, an efficient method to generate and exponentially enhance the cross‐Kerr nonlinearity in quantum optomechanics of two optical cavities coupled to a common mechanical resonator is proposed. Through periodically modulating the mechanical spring constant, a nonlinear two‐phonon drive can be acquired to amplify the mechanical zero‐point fluctuations. As a result, the exponentially enhanced cross‐Kerr interaction between the two optical modes can be realized via the amplified mechanical motion. The distinct feature of this scheme is that a true enhancement of cross‐Kerr nonlinearity can be achieved at the single‐photon level. As intriguing applications, it is also also proposed to generate anticorrelated photon blockade and stabilize one‐photon Fock state based on the enhanced nonlinearity. The present work may provide an appealing way for creating strong cross‐Kerr coupling.