Magnetic phase transition in coherently coupled Bose gases in optical lattices
Anno: 2016
Autori: Barbiero L., Abad M., Recati A.
Affiliazione autori: Univ Padua, Dipartimento Fis & Astron Galileo Galiei, I-35131 Padua, Italy; Univ Trento, CNR, INO, BEC Ctr, I-38123 Povo, Italy; Univ Trento, Dipartimento Fis, I-38123 Povo, Italy; OIST Grad Univ, Quantum Syst Unit, Onna, Okinawa 9040495, Japan; Tech Univ Munich, James Franck Str 1, D-85748 Garching, Germany
Abstract: We describe the ground state of a gas of bosonic atoms with two coherently coupled internal levels in a deep optical lattice in a one-dimensional geometry. In the single-band approximation this system is described by a Bose-Hubbard Hamiltonian. The system has a superfluid and a Mott insulating phase that can be either paramagnetic or ferromagnetic. We characterize the quantum phase transitions at unit filling by means of a density-matrix renormalization-group technique and compare the results with a mean-field approach and an effective spin Hamiltonian. The presence of the ferromagnetic Ising-like transition modifies the Mott lobes. In the Mott insulating region the system maps to the ferromagnetic spin-1/2 XXZ model in a transverse field and the numerical results compare very well with the analytical results obtained from the spin model. In the superfluid regime quantum fluctuations strongly modify the phase transition with respect to the well-established mean-field three-dimensional classical bifurcation.
Giornale/Rivista: PHYSICAL REVIEW A
Volume: 93 (3) Da Pagina: 033645-1 A: 033645-6
Parole chiavi: BOSONSDOI: 10.1103/PhysRevA.93.033645Citazioni: 8dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2023-03-26Riferimenti 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