Transfer of ab initio potential accuracy to liquid helium

Determine whether first-principles helium interaction potentials derived ab initio (including pair, three-body, and four-body terms) can be used to compute thermophysical properties of liquid 4He with accuracy and rigorously propagated uncertainties comparable to those achieved in gas-phase metrological applications.

Background

Ab initio helium interaction potentials have enabled highly precise predictions of gas-phase properties such as virial coefficients, outperforming experimental determinations and supporting primary temperature metrology. In contrast, condensed-phase applications have historically relied on semi-empirical pair potentials and often neglected many-body terms. The paper investigates whether the recent high-accuracy ab initio pair, three-body, and four-body potentials can deliver similarly precise results for liquid 4He.

This uncertainty is central to extending precision standards to the liquid regime, where properties like energy per particle, superfluid fraction, and pair distribution are computed via path-integral Monte Carlo (PIMC) and where systematic uncertainty propagation from ab initio potentials is desired.