Observation of the Hanbury Brown and Twiss Effect with Ultracold Molecules

TL;DR

This paper reports the first observation of the Hanbury Brown and Twiss effect with ultracold molecules, demonstrating quantum statistical correlations using a quantum gas microscope for molecules.

Contribution

It introduces a quantum gas microscope for molecules and observes correlation effects, enabling site-resolved studies of molecular quantum gases.

Findings

Detected bunching correlations in a 2D molecular gas.

Achieved a two-molecule interference pattern with 54% visibility.

Demonstrated the first correlation measurement between single ultracold molecules.

Abstract

Measuring the statistical correlations of individual quantum objects provides an excellent way to study complex quantum systems. Ultracold molecules represent a powerful platform for quantum science due to their rich and controllable internal degrees of freedom. However, the detection of correlations between single molecules in an ultracold gas has yet to be demonstrated. Here we observe the Hanbury Brown and Twiss effect in a gas of bosonic $^{23}$Na$^{87}$Rb, enabled by the realization of a quantum gas microscope for molecules. We detect the characteristic bunching correlations in the density fluctuations of a 2D molecular gas released from and subsequently recaptured in an optical lattice. The quantum gas microscope allows us to extract the positions of individual molecules with single-site resolution. As a result, we obtain a high-contrast two-molecule interference pattern with a visibility of $54(13)\%$. While these measured correlations arise purely from the quantum statistics of the molecules, the demonstrated capabilities pave the way toward site-resolved studies of interacting molecular gases in optical lattices.