Putting a Temperature on Electron Correlation

Abstract:It is common wisdom that a better understanding of how to quantify electron correlation should lead to more efficient treatments of the correlation problem. Here, we not only substantiate this view but turn it into a concrete, systematic framework for ground states. Since prominent correlation measures such as the nonfreeness depend only on the one-particle reduced density matrix, modeling the correlation energy as a function of such a measure naturally places the framework within reduced density matrix functional theory, while keeping the cost at mean-field level. Strikingly, the variable conjugate to the measure emerges as a ``correlation temperature'', thereby connecting correlation measures, functional theory, and effective temperatures. The framework rationalizes methods such as i-DMFT, and we illustrate its key concepts analytically for the Hubbard dimer and numerically for small molecular systems. This brings a fundamental question within reach: how much of the correlation problem can be solved at mean-field cost?

Strongly Correlated Electrons (cond-mat.str-el); Chemical Physics (physics.chem-ph); Quantum Physics (quant-ph)

arXiv:2610.22134 [cond-mat.str-el]

(or arXiv:2610.22134v1 [cond-mat.str-el] for this version)

https://doi.org/10.48550/arXiv.2610.22134 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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