Function sequant::mbpt::open_shell_CC_spintrace

• Defined in File spin.cpp

Function Documentation

std::vector<ExprPtr> sequant::mbpt::open_shell_CC_spintrace(const ExprPtr &expr)

Like open_shell_spintrace but uses minimal expansion of the antisymmetrizer.

This function is designed for integrating spin out of expressions obtained as (k,k)-moment of a fermionic operator: A_{p_1 .. p_k}^{q_1 .. q_k} <a^{p_1 .. p_k}_{q_1 .. q_k} op> with A antisymmetric tensor, op an arbitrary fermionic operator, and the expectation value is with respect to an open-shell Fermi vacuum. Antisymmetrizer is expanded partially to produce antisymmetrizer for spin-up and spin-down columns.

Warning

the “antisymmetrizer” tensor A is assumed to be at the front of each tensor network, hence must use “complete” canonicalization to produce the input expression.

Parameters:

expr – the input expression

Returns:

vector of spin-traced expressions for each spincase