How Estimators Work

How Estimators Work#

Physics, derivations, and computational details behind JaQMC’s built-in estimators. For configuration options, see the estimator sections of each system’s config reference (molecule, solid, hall).

  • Kinetic energy — Laplacian computation, mode trade-offs, spherical variant for FQHE

  • Ewald summation — Coulomb energy in periodic systems via real/reciprocal-space decomposition

  • Pseudopotentials (ECP) — Local and nonlocal core potential contributions, quadrature details

  • Spin-squared — Spin contamination measurement via coordinate-swap ratios

  • Density — Electron density histograms (Cartesian, fractional, and spherical)

  • Loss and gradient — Gradient estimator and outlier clipping

If you are implementing new estimators rather than tuning built-ins, continue with Custom Estimators. For protocol and class-level details, see Estimators.