2010/09/30 by Alexander Mering, Michael Fleischhauer · 2 citations
Physics and Astronomy · #Boson #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Fermi Gamma-ray Space Telescope #Fermion #Hamiltonian (control theory) #Hubbard model #Lattice (music) #Mott insulator #Nonlinear system #Optical lattice #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Quantum tunnelling #Quantum, superfluid, helium dynamics #Superconductivity #Superfluidity #Wannier function #cond-mat.quant-gas
paper · pdf · doi:10.1103/physreva.83.063630
10 pages, 4 figures, submitted to PRA
arxiv created 2011/04/12 · openalex publication_date 2011/06/27 · arxiv updated 2013/05/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Recent experiments revealed the importance of higher-band effects for the Mott-insulator(MI)--superfluid transition(SF) of ultracold bosonic atoms or mixtures of bosons and fermions in deep optical lattices [Best et al., Phys. Rev. Lett. 102, 030408 (2009); Will et al., Nature (London) 465, 197 (2010)]. In the present work we derive an effective lowest-band Hamiltonian in three dimensions that generalizes the standard Bose-Fermi-Hubbard model taking these effects as well as nonlinear corrections of the tunneling amplitudes mediated by interspecies interactions into account. It is shown that a correct description of the lattice states in terms of the bare-lattice Wannier functions, rather than approximations such as harmonic-oscillator states, is essential. In contrast to self-consistent approaches based on effective Wannier functions, our approach captures the observed reduction of the superfluid phase for repulsive interspecies interactions.