Effect of trap symmetry and atom-atom interactions on a trapped atom interferometer with internal state labelling

TL;DR

This paper investigates how trap symmetry and atom-atom interactions influence the coherence and phase behavior of a trapped atom interferometer with internal state labelling, relevant for atomic clocks and inertial sensors.

Contribution

It provides a detailed analysis of the effects of interactions and trap geometry on interferometer performance, including the role of ISRE and strategies to enhance coherence time.

Findings

ISRE can significantly increase spin coherence time in clock configurations.

Trap geometry affects the magnitude of the ISRE effect.

Mean field interactions can counteract trap asymmetries in inertial sensors.

Abstract

In this paper, we study the dynamics of a trapped atom interferometer with internal state labelling in the presence of interactions. We consider two situations: an atomic clock in which the internal states remain superposed, and an inertial sensor configuration in which they are separated. From the average spin evolution, we deduce the fringe contrast and the phase-shift. In the clock configuration, we recover the well-known identical spin rotation effect (ISRE) which can significantly increase the spin coherence time. We also find that the magnitude of the effect depends on the trap geometry in a way that is consistent with our recent experimental results in a clock configuration [M. Dupont-Nivet, and al., New J. Phys., 20, 043051 (2018)], where ISRE was not observed. In the case of an inertial sensor, we show that despite the spatial separation it is still possible to increase the coherence time by using mean field interactions to counteract asymmetries of the trapping potential.