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.
Original language | English |
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Pages (from-to) | 145305 |
Number of pages | 1 |
Journal | Journal of Physics B Atomic Molecular and Optical Physics |
Volume | 42 |
Issue number | 14 |
DOIs | |
Publication status | Published - 1 Jul 2009 |