Hyperfine spectra of trapped Bosons in optical lattices

TL;DR

This paper investigates how the spectral lines of trapped Bose gases in optical lattices are affected by interactions, revealing that the inhomogeneous density distribution causes discrete spectral peaks sensitive to trap imperfections.

Contribution

It provides a detailed calculation of interaction-induced spectral broadening in Bose gases within optical lattices, highlighting the impact of Mott plateau structures on spectral features.

Findings

Spectral lines split into discrete peaks due to Mott plateaus.

Spectra are highly sensitive to density variations and trap imperfections.

Discrete peaks appear even in predominantly superfluid states.

Abstract

We calculate the interaction induced inhomogeneous broadening of spectral lines in a trapped Bose gas as a function of the depth of a three-dimensional cubic optical lattice. As observed in recent experiments, we find that the terraced "wedding-cake" structure of Mott plateaus splits the spectrum into a series of discrete peaks. The spectra are extremely sensitive to density corrugations and trap anharmonicities. For example, even when the majority of the cloud is superfluid the spectrum displays discrete peaks.