Computing the free energy of quantum Coulomb gases and molecules via quantum Gibbs sampling

Abstract:We develop a quantum Gibbs-sampling approach to free-energy estimation for trapped systems of distinguishable particles with Coulomb interactions in dimensions $d\in\{2,3\}$. The singular infinite-dimensional problem is reduced to a finite-rank low-energy truncation of the interaction, the truncated Gibbs state is prepared by a quantum Markov semigroup, and thermodynamic integration gives the free energy. We obtain explicit truncation rates, quantitative spectral-gap estimates, and a finite-dimensional circuit implementation. In particular, every fixed interaction truncation has a positive gap, while weak truncated interactions admit a particle-number-independent lower bound. The circuit complexity is conditional on a certified gap lower bound at the accuracy-dependent interaction cutoff.

arXiv:2604.15263 [quant-ph]

(or arXiv:2604.15263v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2604.15263 Focus to learn more arXiv-issued DOI via DataCite

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