Tan's universal contact and collective oscillations of strongly interacting Fermi gases

TL;DR

This paper investigates the properties of strongly interacting two-component Fermi gases near a Feshbach resonance, focusing on the contact, structure factor, and collective oscillations across the BCS-BEC crossover, with results aligning well with experiments.

Contribution

It introduces a ground state energy functional based on asymptotic limits and Monte Carlo calculations to accurately compute key properties of Fermi gases across the crossover.

Findings

Calculated contact and structure factor agree with recent experiments.

Contact is proportional to the square of the superfluid order parameter.

Provides expressions for chemical potential and polytropic index in terms of energy and contact.

Abstract

We study strongly interacting two component Fermi gas near a Feshbach resonance. By using a ground state energy functional constructed based on asymptotic limits and Monte Carlo calculations, we calculate the contact, structure factor, and collective oscillation frequencies in the BCS-BEC crossover region. The calculated contact and structure factor show excellent agreements with recent experiments. We compare these results with a standard mean-field theory and find that the contact is proportional to the square of superfluid order parameter. Further, we present the chemical potential and the polytropic index in terms of homogenous energy and the contact.