Documentation

The Hubbard-I solver approximates the solution of the impurity model by neglecting any hybridization and solving an atomic problem. The atomic problem is defined by the local interaction Hamiltonian and the orbital dependent high-frequency behavior of the non-interacting bath Green’s function.

C++ reference manual

• Install hubbardI
  • Packaged Versions of hubbardI
  • Compiling hubbardI from source
• Examples
  • Single band Anderson impurity model
  • DFT+DMFT example for Ce with VASP
• Reporting issues
• About hubbardI

Python reference manual

class triqs_hubbardI.Solver(beta, gf_struct, n_iw=1025, n_tau=10001, n_l=30, n_w=500, w_min=-15, w_max=15, idelta=0.01)

Class providing initialization and solve function. Contains all relevant Greensfunctions and self energy.

__init__(beta, gf_struct, n_iw=1025, n_tau=10001, n_l=30, n_w=500, w_min=-15, w_max=15, idelta=0.01)

Initialise the solver.

Parameters:

beta : scalar

Inverse temperature.

gf_struct : list of pairs [ (str,int), …]

Structure of the Green’s functions. It must be a list of pairs, each containing the name of the Green’s function block and its linear size. For example: [ ('up', 3), ('down', 3) ].

n_iw : integer, optional

Number of Matsubara frequencies used for the Green’s functions.

n_tau : integer, optional

Number of imaginary time points used for the Green’s functions.

n_l : integer, optional

Number of legendre polynomials used for the Green’s functions.

n_w : integer, optional

Number of real frequency points used for the Green’s functions.

w_min : integer, optional

Lower limit of the range of real frequencies

w_max : integer, optional

Upper limit of the range of real frequencies

idelta : float, optional

Broadening of Green’s function on real frequencies

solve(**params_kw)

Solve the impurity problem: calculate G(iw) and Sigma(iw)

Parameters:

params_kw : dict {‘param’:value} that is passed to the core solver.

Only required parameter is

• h_int (Operator object): the local Hamiltonian of the impurity problem to be solved,

Other parameters are

• calc_gtau (bool): calculate G(tau)

• calc_gw (bool): calculate G(w) and Sigma(w)

• calc_gl (bool): calculate G(legendre)

• calc_dm (bool): calculate density matrix