Generation of spin squeezing via a fully quantum degenerate parametric amplifier

Abstract

Spin squeezing is one of the most attractive methods for realizing high-precision metrology. In this paper we propose a protocol for generating spin squeezing in an atomic ensemble via a fully quantum degenerate parametric amplifier. We discuss the properties of generating spin squeezing with and without driving the pump cavity. Numerical simulation results show that the generated spin squeezing strength is sizable and is comparable to that obtained using a two-axis twisting model. Moreover, we demonstrate that the protocol is experimentally feasible by introducing the corresponding experimental parameters. Therefore, the proposed protocol provides a promising approach to realize spin squeezing in photon-spin coupling systems.