Atomic clock interferometry using optical tweezers

Clock interferometry refers to the coherent splitting of a clock into two different paths and recombining in a way that reveals the proper-time difference between them. Unlike the comparison of two separate clocks, this approach allows testing how nonflat space-time influences quantum coherence. Atomic clocks are currently the most accurate timekeeping devices. Here we propose using optical tweezers to implement clock interferometry. Our proposed clock interferometer employs an alkaline-earth-like atom held in an optical trap at the magic wavelength. Through a combination of adiabatic, tweezer-based splitting and recombining schemes and a modified Ramsey sequence of the clock states, we achieve linear sensitivity to the gravitational time dilation. Moreover, the measurement of the time dilation is insensitive to relative fluctuations in the intensity of the tweezer beams. We analyze the tweezer clock interferometer and show that it is feasible with current technological capabilities. The proposed interferometer could test the effect of gravitational redshift on quantum coherence and implement the quantum twin paradox.