Quasi-1D atomic gases across wide and narrow confinement-induced-resonances

TL;DR

This paper investigates the behavior of quasi-one-dimensional atomic gases near wide and narrow confinement-induced resonances, revealing how interaction properties and thermodynamics depend on resonance width and how the repulsive scattering branch evolves across the resonance.

Contribution

It provides a detailed analysis of the interaction dynamics and thermodynamics of quasi-1D gases across wide and narrow CIRs, highlighting the dependence on resonance width and the stability of the repulsive branch.

Findings

Repulsive scattering branch can cross CIR without decay at low fields.

Universal thermodynamics applies at wide CIR but not at narrow CIR.

Interaction energy shows asymmetry near decay points depending on resonance width.

Abstract

We study quasi-one-dimensional atomic gases across wide and narrow confinement-induced-resonances (CIR). We show from Virial expansion that by tuning the magnetic field, the repulsive scattering branch initially prepared at low fields can continuously go across CIR without decay; instead, the decay occurs when approaching the non-interacting limit. The interaction properties essentially rely on the resonance width of CIR. Universal thermodynamics holds for scattering branch right at wide CIR, but is smeared out in narrow CIR due to strong energy-dependence of coupling strength. In wide and narrow CIR, the interaction energy of scattering branch shows different types of strong asymmetry when approaching the decay from opposite sides of magnetic field. Finally we discuss the stability of repulsive branch for a repulsively interacting Fermi gas in different trapped geometries at low temperatures.