Phase Diagram of the Bose-Hubbard Model with T_3 symmetry
| dc.creator | Rizzi, M. | |
| dc.creator | Cataudella, V. | |
| dc.creator | Fazio, R. | |
| dc.date | 2005-10-13 | |
| dc.date.accessioned | 2026-07-07T06:44:21Z | |
| dc.date.available | 2026-07-07T06:44:21Z | |
| dc.description | In this paper we study the quantum phase transition between the insulating and the globally coherent superfluid phases in the Bose-Hubbard model with T_3 structure, the "dice lattice". Even in the absence of any frustration the superfluid phase is characterized by modulation of the order parameter on the different sublattices of the T_3 structure. The zero-temperature critical point as a function of a magnetic field shows the characteristic "butterfly" form. At fully frustration the superfluid region is strongly suppressed. In addition, due to the existence of the Aharonov-Bohm cages at f=1/2, we find evidence for the existence of an intermediate insulating phase characterized by a zero superfluid stiffness but finite compressibility. In this intermediate phase bosons are localized due to the external frustration and the topology of the T_3 lattice. We name this new phase the Aharonov-Bohm (AB) insulator. In the presence of charge frustration the phase diagram acquires the typical lobe-structure. The form and hierarchy of the Mott insulating states with fractional fillings, is dictated by the particular topology of the T_3 lattice. The results presented in this paper were obtained by a variety of analytical methods: mean-field and variational techniques to approach the phase boundary from the superconducting side, and a strongly coupled expansion appropriate for the Mott insulating region. In addition we performed Quantum Monte Carlo simulations of the corresponding (2+1)D XY model to corroborate the analytical calculations with a more accurate quantitative analysis. We finally discuss experimental realization of the T_3 lattice both with optical lattices and with Josephson junction arrays. | |
| dc.description | 16 pages, 17 figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0510341 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0510341 | |
| dc.identifier | Phys. Rev. B 73, 144511 (2006) | |
| dc.identifier | doi:10.1103/PhysRevB.73.144511 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/102751 | |
| dc.subject | Superconductivity | |
| dc.title | Phase Diagram of the Bose-Hubbard Model with T_3 symmetry | |
| dc.type | text |