Excitation spectrum of Mott shells in optical lattices
Abstract
We theoretically study the excitation spectrum of confined macroscopic optical lattices in the Mott-insulating limit. For large systems, a fast numerical method is proposed to calculate the ground state filling and excitation energies. We introduce many-particle on-site energies capturing multi-band effects and discuss tunnelling on a perturbative level using an effectively restricted Hilbert space. Results for small one-dimensional lattices obtained by this method are in good agreement with the exact multi-band diagonalization of the Hamiltonian. Spectral properties associated with the formation of regions with constant filling, so-called Mott shells, are investigated and interfaces between the shells with strong particle fluctuations are characterized by gapless local excitations.
Keywords
Cite
@article{arxiv.0906.5229,
title = {Excitation spectrum of Mott shells in optical lattices},
author = {Dirk-Sören Lühmann and Kai Bongs and Daniela Pfannkuche},
journal= {arXiv preprint arXiv:0906.5229},
year = {2009}
}