The effect of laser noise on Rabi oscillation fidelity

We study the effect of laser noise on one- and two-photon Rabi oscillations with realistic noise models with the goal of quantifying the influence of laser noise on neutral atom quantum gate fidelity. First we study the relation between self-heterodyne measurements, the laser lineshape,  and its underlying phase noise features, and power spectral density. There is a universal relation satisfied between the two quantities for locked and well-filtered lasers with low noise, which is useful for practical experiments. Noise spectra that include servo bump features are modeled analytically.

We simulate the effect of laser noise on the fidelity and coherence of one-photon and two-photon Rabi oscillations by reconstructing samples of time-varying phase noise with realistic parameters, extracted from laboratory heterodyne measurements. We also propose quasi-static models for calculating the effect of phase and intensity noise. The models can be used when the bandwidth of the power spectral density for the phase and frequency noise is much smaller than the Rabi frequency. We compare the results of the quasi-static model with simulations for one and two-photon Rabi oscillations.