triqs_modest.module.U_matrix_in_spherical_basis

triqs_modest.module.U_matrix_in_spherical_basis()

Function dispatched to the following (C++) functions:

[1] (l: int, U_int: float, J_hund: float)
  -> ndarray[float, 4]

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Construct a four-index Coulomb tensor in the basis of spherical harmonics.

We typically construct the four-index Coulomb tensor in the basis of spherical harmonics, $$ U_{m_{1}m_{2}m_{3}m_{4}}^{{spherical}} = _{k=0}^{2l} F_{k} (l, k, m_{1}, m_{2}, m_{3}, m_{4}),$$ where $F_{k}$ are radial Slater integrals and

Utility functions for creating and working with the four index Coulomb tensor. @ {

denote angular Racah-Wigner numbers for a spherically symmetric interaction tensor.

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Parameters

l:

angular quantum number

U_int:

screend Hubbard interaction

J_hund:

Hund’s coupling

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Returns

nda::array<double, 4>

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