Sodium Bose-Einstein Condensates in an Optical Lattice

TL;DR

This paper reports the observation of a superfluid to Mott insulator phase transition in a sodium Bose-Einstein condensate within a three-dimensional optical lattice, highlighting effects of laser detuning and atom loss mechanisms.

Contribution

It demonstrates the phase transition in sodium BECs in an optical lattice and investigates atom loss due to photoassociation at specific lattice detunings.

Findings

Observation of superfluid to Mott insulator transition in Na BECs.

Identification of atom loss mechanisms related to photoassociation.

Effects of laser detuning on atom lifetime and lattice stability.

Abstract

The phase transition from a superfluid to a Mott insulator has been observed in a $^{23}$Na Bose-Einstein condensate. A dye laser detuned $\approx 5$nm red of the Na $3^2$S$ \to 3^2$P$_{1/2}$ transition was used to form the three dimensional optical lattice. The heating effects of the small detuning as well as the three-body decay processes constrained the timescale of the experiment. Certain lattice detunings were found to induce a large loss of atoms. These loss features were shown to be due to photoassociation of atoms to vibrational levels in the Na$_2$ $(1) ^3\Sigma_g^+$ state.