Cluster Gutzwiller for bosons in optical lattices

3 April 2013

Photo: AG Sengstock

By treating clusters within the Gutzwiller theory, a surprisingly good description of quantum fluctuations beyond the mean-field theory is achieved approaching quantum Monte-Carlo predictions for large clusters. Applying this powerful method to the Bose-Hubbard model, we demonstrate that it yields precise results for the superfluid to Mott-insulator transition in square, honeycomb, and cubic lattices. Due to the exact treatment within a cluster, the method can be effortlessly adapted to more complicated Hamiltonians in the fast progressing field of optical lattice experiments. We discuss the perspectives that allow for the computation of large, spatially-varying lattices, low-lying excitations, and time evolution.

Phys. Rev. A 87, 043619 (2013)

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