Breakdown of universality in few-boson systems

TL;DR

This paper investigates the limits of universality in few-boson systems by using tailored two-boson potentials and reveals conditions under which universal predictions fail in three- and four-body scenarios.

Contribution

It introduces a series of short-range potentials that reproduce identical two-body observables but show deviations from universal behavior in few-body systems.

Findings

Universal behavior can be strongly violated in few-boson systems.

Conditions for the breakdown of universality are identified.

Effective field theory predictions may not always hold in these systems.

Abstract

We develop a series of resonant short-range two-boson potentials reproducing the same two-body low-energy observables and apply them in three- and four-body calculations. We demonstrate that the universal behavior predicted by effective field theory may be strongly violated and analyze the conditions for this phenomenon.