Gutzwiller approach to the Bose-Hubbard model with random local impurities

Year: 2009

Authors: Buonsante P., Massel F., Penna V., Vezzani A.

Autors Affiliation: CNISM Unità di Ricerca Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy; Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy; CNR-INFM, S3, National Research Center, Dipartimento di Fisica, via Campi 213/a, 41100 Modena, Italy; Dipartimento di Fisica, Università degli Studi di Parma Viale G.P. Usberti 7/a, I-43100 Parma, Italy

Abstract: Recently it has been suggested that fermions whose hopping amplitude is quenched to extremely low values provide a convenient source of local disorder for lattice bosonic systems realized in current experiment on ultracold atoms. Here we investigate the phase diagram of such systems, which provide the experimental realization of a Bose-Hubbard model whose local potentials are randomly extracted from a binary distribution. Adopting a site-dependent Gutzwiller description of the state of the system, we address one- and two-dimensional lattices and obtain results agreeing with previous findings, as far as the compressibility of the system is concerned. We discuss the expected peaks in the experimental excitation spectrum of the system, related to the incompressible phases, and the superfluid character of the partially compressible regions characterizing the phase diagram of systems with binary disorder. In our investigation we make use of several analytical results whose derivation is described in appendixes, and whose validity is not limited to the system under concern.

Journal/Review: PHYSICAL REVIEW A

Volume: 79 (1)      Pages from: 013623  to: 013623

KeyWords: bose-hubbard; ultracold bosons; disordered system; quantum phase transition;
DOI: 10.1103/PhysRevA.79.013623

Citations: 29
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