Collective excitations of a trapped Bose-Einstein condensate in the presence of a 1D optical lattice

TL;DR

This paper investigates how a one-dimensional optical lattice affects the collective excitations of a trapped Bose-Einstein condensate, providing experimental data to test a recent theoretical model.

Contribution

It offers the first detailed experimental analysis of collective modes in a BEC with a 1D optical lattice, validating a new theoretical framework.

Findings

Transverse breathing mode remains unaffected by the lattice.

Quadrupole and dipole modes are significantly altered by the optical potential.

Experimental measurements align with the theoretical model.

Abstract

We study low-lying collective modes of a horizontally elongated 87Rb condensate produced in a 3D magnetic harmonic trap with the addition of a 1D periodic potential which is provided by a laser standing-wave along the horizontal axis. While the transverse breathing mode results unperturbed, quadrupole and dipole oscillations along the optical lattice are strongly modified. Precise measurements of the collective mode frequencies at different height of the optical barriers provide a stringent test of the theoretical model recently introduced [M.Kraemer et al. Phys. Rev. Lett. 88 180404 (2002)].