Fig. 4: SC state interferometer.
From: Large array of Schrödinger cat states facilitated by an optical waveguide
a Protocol for creating the SC state in phase space representation. The top and bottom columns represent |↑> and |↓>, respectively. The circles in red indicate the uncertainty in the ground state and the coherent state. The microwave π/2 and π pulses are used to manipulate the internal spin states. The displacement operator D̂(α) and D̂(αeiϕ) are created by driving lasers pulses. b Interference fringes of the SC state interferometer. The population of atoms in |↑> state P↑ is measured with the relative phase ϕ of the two driving lasers pulses for different pulse durations. Error bars are the standard error of the mean of four experimental runs. c Even and odd SC states. The population of atoms in |↑> state P↑ is measured with the relative phase ϕ of the two driving lasers pulses for δM = 0 (odd SC state) and δM = π (even SC state). The driving lasers pulse duration is 0.45 μs. Error bars are the standard error of the mean of four experimental runs. d Fitting parameters of Eq. (4) for the experimental data in panel b is plotted against different driving lasers pulse duration. e Measurements of the |↑> state population P↑ in cat interferometer operation versus phase ϕ with additional free evolution time τ. The total free evolution time between the two driving lasers pulses for τ = 1 μs is 16 μs. Error bars are the standard error of the mean of four experimental runs. f Simulation of the temperature effect on the SC state interferometer. The simulation uses the fitted parameters for t = 0.45 μs in panel d. The 1/e Gaussian radius of the atomic cloud in the radial direction is 0.9 μm and 8 μm for 2 μK and 150 μK, respectively.
