Robust sub-shot-noise measurement via Rabi-Josephson oscillations in bimodal Bose-Einstein condensates

TL;DR

This paper demonstrates that monitoring Rabi-Josephson oscillations in bimodal Bose-Einstein condensates enables robust sub-shot-noise measurements, maintaining high sensitivity even with strong interactions, by optimizing number squeezing.

Contribution

It introduces a method to use Rabi-Josephson oscillations for robust, sub-shot-noise atom interferometry, overcoming limitations of phase-squeezing under interactions.

Findings

Sub-shot-noise scaling retained with strong interactions.

Number squeezing optimizes sensitivity and robustness.

Monitoring Rabi-Josephson oscillations improves measurement stability.

Abstract

Mach-Zehnder atom interferometry requires hold-time phase-squeezing to attain readout accuracy below the standard quantum limit. This increases its sensitivity to phase-diffusion, restoring shot-noise scaling of the optimal signal-to-noise ratio, $s_o$, in the presence of interactions. The contradiction between the preparations required for readout accuracy and robustness to interactions, is removed by monitoring Rabi-Josephson oscillations instead of relative-phase oscillations during signal acquisition. Optimizing $s_o$ with a Gaussian squeezed input, we find that hold-time number squeezing satisfies both demands and that sub-shot-noise scaling is retained even for strong interactions.