Excitation spectrum of Mott shells in optical lattices

Dirk-Sören Lühmann; Kai Bongs; Daniela Pfannkuche

doi:10.1088/0953-4075/42/14/145305

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arXiv · 0906.5229

Excitation spectrum of Mott shells in optical lattices

Dirk-Sören Lühmann·Kai Bongs·Daniela Pfannkuche

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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.

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Dirk-Sören Lühmann, Kai Bongs, Daniela Pfannkuche. 2009-06-29. Excitation spectrum of Mott shells in optical lattices. https://doi.org/10.1088/0953-4075/42/14/145305

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