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-Hua^{1, 4, †}, Qu Ze-Yu^{1, 3}, Zhang Wei-Ping^{2, 4}

(color online) The optimal QFIs versus the total input mean photon number N_in. The dotted-dashed line and the dashed line are the two coherent states input and coherent ⊗ squeezed state input, respectively. The solid line is the Hofmann limit with coherent ⊗ squeezed state input g = 1.5.