https://doi.org/10.1140/epja/i2008-10537-2
Regular Article - Theoretical Physics
The symmetric heavy-light ansatz
Department of Physics, North Carolina State University, 27695, Raleigh, NC, USA
* e-mail: dean_lee@ncsu.edu
Received:
12
February
2008
Accepted:
13
February
2008
Published online:
7
March
2008
The symmetric heavy-light ansatz is a method for finding the ground state of any dilute unpolarized system of attractive two-component fermions. Operationally it can be viewed as a generalization of the Kohn-Sham equations in density functional theory applied to N -body density correlations. While the original Hamiltonian has an exact Z2 symmetry, the heavy-light ansatz breaks this symmetry by skewing the mass ratio of the two components. In the limit where one component is infinitely heavy, the many-body problem can be solved in terms of single-particle orbitals. The original Z2 symmetry is recovered by enforcing Z2 symmetry as a constraint on N -body density correlations for the two components. For the 1D, 2D, and 3D attractive Hubbard models the method is in very good agreement with exact Lanczos calculations for few-body systems at arbitrary coupling. For the 3D attractive Hubbard model there is very good agreement with lattice Monte Carlo results for many-body systems in the limit of infinite scattering length.
PACS: 03.75.Ss Degenerate Fermi gases – / 21.65.Cd Asymmetric matter, neutron matter – / 71.10.Fd Lattice fermion models (Hubbard model, etc.) –
© Società Italiana di Fisica and Springer-Verlag, 2008
