Improved lattice operators for non-relativistic fermions

TL;DR

This paper introduces improved lattice operators for non-relativistic fermions, reducing finite lattice spacing effects and enhancing the accuracy of energy and contact calculations in lattice simulations.

Contribution

It applies a new improvement procedure to construct highly improved operators for energy and contact, advancing finite-temperature lattice calculations for dilute Fermi systems.

Findings

Improved operators reduce finite lattice spacing effects.

Enhanced accuracy in energy and contact calculations.

Demonstrated improvements in a ground-state lattice calculation at unitarity.

Abstract

In this work I apply a recently proposed improvement procedure, originally conceived to reduce finite lattice spacing effects in transfer matrices for dilute Fermi systems, to tuning operators for the calculation of observables. I construct, in particular, highly improved representations for the energy and the contact, as a first step in an improvement program for finite-temperature calculations. I illustrate the effects of improvement on those quantities with a ground-state lattice calculation at unitarity.