Sub-Poissonian fluctuations in a 1D Bose gas: from the quantum quasi-condensate to the strongly interacting regime

TL;DR

This study investigates atom number fluctuations in a 1D Bose gas, revealing a transition from super- to sub-Poissonian statistics across different interaction regimes, highlighting quantum effects and fermionization.

Contribution

It provides the first detailed experimental measurement of local atom number fluctuations across weak to strong interactions in a 1D Bose gas.

Findings

Super-Poissonian fluctuations at intermediate densities in weakly interacting gases.

Sub-Poissonian fluctuations at high densities in the quantum quasi-condensate regime.

Fluctuations transition from Poissonian to sub-Poissonian approaching fermionization.

Abstract

We report on local measurements of atom number fluctuations in slices of a single 1D Bose gas with repulsive interactions. For weakly interacting gases, the fluctuations are super-Poissonian at intermediate atomic densities and become sub-Poissonian at high densities once the gas enters into the quantum quasi-condensate regime. At stronger interactions, when approaching the fermionization regime, we no longer observe super-Poissonian statistics; the fluctuations go from Poissonian to sub-Poissonian as the density is increased, as those in a Fermi gas.