Atom interferometry with a weakly-interacting Bose Einstein condensate

TL;DR

This paper demonstrates a highly coherent atom interferometer using a weakly interacting Bose-Einstein condensate of potassium-39, achieved by tuning interactions via a Feshbach resonance, enabling high spatial resolution force measurements.

Contribution

The authors show how to significantly reduce interaction-induced decoherence in a trapped BEC interferometer by tuning the scattering length near zero, extending coherence times.

Findings

Achieved coherence times of several hundred milliseconds.

Controlled the scattering length with better than 0.1 $a_0$ precision.

Demonstrated potential for high spatial resolution force sensing.

Abstract

We demonstrate the operation of an atom interferometer based on a weakly interacting Bose-Einstein condensate. We strongly reduce the interaction induced decoherence that usually limits interferometers based on trapped condensates by tuning the s-wave scattering length almost to zero via a magnetic Feshbach resonance. We employ a $^{39}$K condensate trapped in an optical lattice, where Bloch oscillations are forced by gravity. With a control of the scattering length better that 0.1 $a_0$ we achieve coherence times of several hundreds of ms. The micrometric sizes of the atomic sample make our sensor an ideal candidate for measuring forces with high spatial resolution. Our technique can be in principle extended to other measurement schemes opening new possibilities in the field of trapped atom interferometry.