Browsing by Subject "Mean field theory"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Dimensional crossover in two-dimensional Bose-Fermi mixtures
    (Institute of Physics Publishing, 2010) Subaşi, A. L.; Sevinçli, S.; Vignolo, P.; Tanatar, Bilal
    We investigate the equilibrium properties of boson-fermion mixtures consisting of a Bose condensate and spin-polarized Fermi gas confined in a harmonic two-dimensional (2D) trap using mean-field theory. Boson-boson and boson-fermion coupling constants have a logarithmic dependence on the density because of the two-dimensional scattering events when the s-wave scattering lengths are on the order of mixture thickness. We show that this modifies the density profiles significantly. It is also shown that the dimensional crossover stabilizes the mixture against collapse and spatial demixing is observed for the case of a negative boson-fermion scattering length.
  • Thumbnail Image
    ItemOpen Access
    Pairing and vortex lattices for interacting fermions in optical lattices with a large magnetic field
    (The American Physical Society, 2010) Zhai, H.; Umucalılar, R. O.; Oktel, M. Ö.
    We study the structure of a pairing order parameter for spin-1/2 fermions with attractive interactions in a square lattice under a uniform magnetic field. Because the magnetic translation symmetry gives a unique degeneracy in the single-particle spectrum, the pair wave function has both zero and finite-momentum components coexisting, and their relative phases are determined by a self-consistent mean-field theory. We present a microscopic calculation that can determine the vortex lattice structure in the superfluid phase for different flux densities. Phase transition from a Hofstadter insulator to a superfluid phase is also discussed.
  • Thumbnail Image
    ItemOpen Access
    Two-dimensional boson-fermion mixtures
    (2009) Subaşi, A.L.; Sevinçli, S.; Vignolo P.; Tanatar, Bilal
    Using mean-field theory, we study the equilibrium properties of boson-fermion mixtures confined in a harmonic pancake-shaped trap at zero temperature. When the modulus of the s -wave scattering lengths are comparable to the mixture thickness, two-dimensional scattering events introduce a logarithmic dependence on density in the coupling constants, greatly modifying the density profiles themselves. We show that, for the case of a negative boson-fermion three-dimensional s -wave scattering length, the dimensional crossover stabilizes the mixture against collapse and drives it toward spatial demixing. © 2009 The American Physical Society.