Chen-Can Wang | Searcharxiv

arXiv2026

Observation of renormalization group invariance in symmetry-restored nuclear lattice effective field theory

Renormalization group (RG) invariance implies that the predictions of effective field theory are independent of the momentum cutoffs introduced during regularization. Here we report the first systematic verification of RG invariance for realistic nuclear few-body systems within nuclear lattice effective field theory. To restore broken continuum rotational and Galilean symmetries, we employ Galilean-invariance-restoration counterterms and use a soft momentum regulator. We calibrate the two- and three-body next-to-next-to leading order (N$^2$LO) chiral forces using $A\leq 3$ observables and perform precision quantum Monte Carlo calculations to compute the $^4$He binding energy. The predicted energy remains constant across cutoffs from $250$~MeV to $400$~MeV and agrees well with the experimental value, with discrepancies of order 100 keV. Our results demonstrate the capability of extracting accurate, cutoff-independent predictions within lattice-regulated \textit{ab initio} nuclear theory.

nucl-th↗

arXiv2026

Cutoff-independent predictions from nuclear lattice effective field theory

Cutoff independence is an essential requirement for the predictive power of nuclear \textit{ab initio} calculations based on effective field theory (EFT). While it is conventionally assumed that such invariance necessitates high-order interactions and complex many-body forces, we present a minimal chiral nuclear force that exhibits remarkable cutoff independence across a broad range from light to medium-mass nuclei and sub-saturated nuclear matter. Our framework comprises only contact terms up to next-to-leading order, a single three-nucleon contact force, and a leading-order one-pion-exchange potential, all constrained strictly in the $A \leq 3$ sector. Despite its simplicity, this interaction accurately reproduces experimental binding energies up to $^{40}\text{Ca}$ with unexpectedly small residual cutoff dependencies of only a few MeV. We demonstrate that the use of a lattice-inspired \emph{absolute}-momentum regulator efficiently suppresses high-momentum modes, resolving the overbinding problem for soft chiral forces without invoking complex many-body forces. These results establish a robust and economic foundation for EFT-based \textit{ab initio} calculations in both continuum and lattice frameworks.

nucl-th↗