Fractional-filling loophole insulator domains for ultracold bosons in optical superlattices
Anno: 2004
Autori: Buonsante P., Penna V., Vezzani A.
Affiliazione autori: Dipartimento di Fisica, Politecnico di Torino and INFM, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy; Dipartimento di Fisica, Università degli Studi di Parma and INFM, Parco Area delle Scienze 7/a, I-43100 Parma, Italy
Abstract: The zero-temperature phase diagram of a Bose-Einstein condensate confined in realistic one-dimensional l-periodic optical superlattices is investigated. The system of interacting bosons is modeled in terms of a Bose-Hubbard Hamiltonian whose site-dependent local potentials and hopping amplitudes reflect the periodicity of the lattice partition in l-site cells. Relying on the exact mapping between the hardcore limit of the boson Hamiltonian and the model of spinless noninteracting fermions, incompressible insulator domains are shown to exist for rational fillings that are predicted to be compressible in the atomic limit. The corresponding boundaries, qualitatively described in a multiple-site mean-field approach, are shown to exhibit an unusual loophole shape. A more quantitative description of the loophole domain boundaries at half filling for the special case l=2 is supplied in terms of analytic strong-coupling expansions and quantum Monte Carlo simulations.
Giornale/Rivista: PHYSICAL REVIEW A
Volume: 70 (6) Da Pagina: 061603-1 A: 061603-4
Maggiori informazioni: Rapid CommunicationParole chiavi: ultracold atoms; optical lattices; superlattices; phase diagram; DOI: 10.1103/PhysRevA.70.061603Citazioni: 55dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2024-05-12Riferimenti tratti da Isi Web of Knowledge: (solo abbonati) Link per visualizzare la scheda su IsiWeb: Clicca quiLink per visualizzare la citazioni su IsiWeb: Clicca qui