Lattice Regularization of Non-relativistic Interacting Fermions in One Dimension

TL;DR

This paper investigates few-body systems of two-species non-relativistic fermions in one dimension, analyzing how lattice discretization affects interaction coupling and ground state energies, with implications for ultra-cold quantum gases.

Contribution

It introduces a systematic approach to study discretization effects on few-body fermionic systems using lattice and field theory methods, providing benchmarks against continuum results.

Findings

Coupling dependence on lattice spacing characterized.

Ground state energies benchmarked against continuum theory.

Discretization effects on few-body observables systematically analyzed.

Abstract

Few-body physics plays a central role in many branches of physics, such as nuclear physics and atomic physics. Advances in controlling ultra-cold quantum gases provide an ideal testbed for few-body physics theory. In this work, we study few-body systems consisting of two distinct species of non-relativistic fermions in one spatial dimension using both field theory and lattice methods. Particles of the same type do not interact with each other, but particles of different types can interact via an attractive contact interaction. We first study the dependence of the coupling of a contact interaction on the lattice spacing. Using this input, we extract two-, three-, and four-body ground state energies in the infinite length limit and benchmark them against the calculations from the continuum field theory. This work enables us to systematically study the effect of discretization and finite-length artifacts on few-body observables.