Measuring nonlocal three-body spatial correlations with Rydberg trimers in ultracold quantum gases

TL;DR

This paper measures nonlocal three-body correlations in ultracold strontium gases by studying trimer Rydberg molecule formation, revealing quantum statistical effects and enabling future in situ correlation studies.

Contribution

It introduces an experimental method to quantify nonlocal three-body correlations in ultracold gases via Rydberg molecule formation, showing quantum statistical effects.

Findings

Enhanced trimer formation in bosonic $^{84}$Sr due to bunching

Reduced formation in fermionic $^{87}$Sr due to anti-bunching

Good agreement between experimental results and theory

Abstract

We measure nonlocal third-order spatial correlations in non-degenerate ultracold gases of bosonic ($^{84}$Sr) and spin-polarized fermionic ($^{87}$Sr) strontium through studies of the formation rates for ultralong-range trimer Rydberg molecules. The trimer production rate is observed to be very sensitive to the effects of quantum statistics with a strong enhancement of up to a factor of six (3!) in the case of bosonic $^{84}$Sr due to bunching, and a marked reduction for spin-polarized fermionic $^{87}$Sr due to anti-bunching. The experimental results are compared to theoretical predictions and good agreement is observed. The present approach opens the way to {\it{in situ}} studies of higher-order nonlocal spatial correlations in a wide array of ultracold atomic-gas systems.