Lattice calculation for unitary fermions in a finite box

TL;DR

This paper reports on lattice calculations of the Bertsch parameter and pairing gap for unitary fermions, using correlation functions for up to 38 particles in a finite box, highlighting challenges in many-body lattice studies.

Contribution

It introduces a lattice construction method for unitary fermions and computes key physical parameters, advancing the understanding of strongly interacting fermionic systems.

Findings

Computed the Bertsch parameter and pairing gap for up to 38 fermions

Identified challenges in simulating many-body states on the lattice

Provided insights relevant to QCD calculations

Abstract

A fundamental constant in systems of unitary fermions is the so-called Bertsch parameter, the ratio of the ground state energy for spin paired unitary fermions to that for free fermions at the same density. I discuss how we computed this parameter as well as the pairing gap using a recently developed lattice construction for unitary fermions, by measuring correlation functions for up to 38 fermions in a finite box. Our calculation illustrates interesting issues facing the study of many-body states on the lattice, which may eventually be confronted in QCD calculations as well.