Contact and Momentum Distribution of the Unitary Fermi Gas

TL;DR

This paper presents precise measurements of the contact and momentum distribution in a unitary Fermi gas, resolving discrepancies among theoretical models and providing benchmarks for future research.

Contribution

It offers the first accurate data for the contact and momentum distribution at unitarity using Bold Diagrammatic Monte Carlo and Borel resummation, addressing existing theoretical disagreements.

Findings

Results agree with experimental data within error bars.

Provides benchmarks for theoretical development.

Clarifies temperature dependence of the contact.

Abstract

A key quantity in strongly-interacting resonant Fermi gases is the contact $\mathcal{C}$, which characterizes numerous properties such as the momentum distribution at large momenta or the pair correlation function at short distances. The temperature dependence of $\mathcal{C}$ was measured at unitarity, where existing theoretical predictions differ substantially even at the qualitative level. We report accurate data for the contact and the momentum distribution of the unitary gas in the normal phase, obtained by Bold Diagrammatic Monte Carlo and Borel resummation. Our results agree with experimental data within error bars and provide crucial benchmarks for the development of advanced theoretical treatments and precision measurements.