Phase estimation of phase shifts in two arms for an SU(1,1) interferometer with coherent and squeezed vacuum states
Gong Qian-Kun1, Li Dong1, Yuan Chun-Hua1, 4, †, Qu Ze-Yu1, 3, Zhang Wei-Ping2, 4
       

(color online) Schematic diagram of the parameter estimation process based on the SU(1,1) interferometer. g and θg describe the strength and phase in the first NBS process, respectively. a and b denote two light modes in the interferometer. In the Schrödinger picture, the initial state ⎸Ψin〉 injecting into a NBS results in the output ⎸Ψ〉, and the state is transformed as ⎸Ψϕ〉 after phase shifts. NBS: nonlinear beam splitter. ϕ1, ϕ2: phase shifts. M: mirrors.