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Convert two-body operator coefficients to low rank tensor.
openfermion.circuits.get_chemist_two_body_coefficients(
two_body_coefficients, spin_basis=True
)
The input is a two-body fermionic Hamiltonian expressed as \(\sum_{pqrs} h_{pqrs} a^\dagger_p a^\dagger_q a_r a_s\)
We will convert this to the chemistry convention expressing it as \(\sum_{pqrs} g_{pqrs} a^\dagger_p a_q a^\dagger_r a_s\) but without the spin degree of freedom.
In the process of performing this conversion, constants and one-body terms come out, which will be returned as well.
Args | |
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| two_bodycoefficients (ndarray): an N x N x N x N numpy array giving the \(h{pqrs}\) tensor. spin_basis (bool): True if the two-body terms are passed in spin orbital basis. False if already in spatial orbital basis. |
Returns | |
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| one_body_correction (ndarray): an N x N array of floats giving coefficients of the \(a^\dagger_p a_q\) terms that come out. chemist_two_bodycoefficients (ndarray): an N x N x N x N numpy array giving the \(g{pqrs}\) tensor in chemist notation. |
Raises | |
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TypeError
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Input must be two-body number conserving FermionOperator or InteractionOperator. |