March 1, 2023
Journal Article

Sub-system self-consistency in coupled cluster theory


In this Communication, we provide numerical evidence indicating that the standard single-reference coupled-cluster (CC) energies can be calculated alternatively to its copybook definition. We demonstrate that the CC energies can be reconstructed by diagonalizing the effective Hamiltonians describing correlated sub-systems of the many-body system. In the extreme case, we provide numerical evidence that the CC energy can be reproduced through the diagonalization of the effective Hamiltonian describing sub-system composed of a single electron. These properties of CC formalism can be exploited to design protocols to define effective interactions in sub-systems used as a probe to calculate the energy of the entire system and introduce a new type of self-consistency for approximate CC approaches.

Published: March 1, 2023


Kowalski K. 2023. Sub-system self-consistency in coupled cluster theory. The Journal of Chemical Physics 158, no. 5:Art. No. 054101. PNNL-SA-177621. doi:10.1063/5.0125696

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