Local observation of antibunching in a trapped Fermi gas

TL;DR

This paper reports the local observation of antibunching in a trapped Fermi gas, demonstrating quantum degeneracy effects and using density fluctuation analysis to probe temperature.

Contribution

It provides the first local measurement of antibunching in a trapped Fermi gas and links density fluctuations to quantum degeneracy via the fluctuation-dissipation theorem.

Findings

Suppression of density fluctuations in the quantum degenerate regime.

Observation of atomic shot noise in the non-degenerate regime.

Fluctuation-based temperature measurement consistent with other methods.

Abstract

Local density fluctuations and density profiles of a Fermi gas are measured in-situ and analyzed. In the quantum degenerate regime, the weakly interacting $^6$Li gas shows a suppression of the density fluctuations compared to the non-degenerate case, where atomic shot noise is observed. This manifestation of antibunching is a direct result of the Pauli principle and constitutes a local probe of quantum degeneracy. We analyze our data using the predictions of the fluctuation-dissipation theorem and the local density approximation, demonstrating a fluctuation-based temperature measurement.