A simple mean field equation for condensates in the BEC-BCS crossover regime

TL;DR

This paper introduces a mean field equation for fermionic atom pairs to describe condensates across the BEC-BCS crossover, accurately matching quantum Monte Carlo results and elucidating the transition from molecular to atomic behavior.

Contribution

It proposes a new mean field approach based on pairs of fermionic atoms, providing a unified description of condensates in the BEC-BCS crossover regime.

Findings

Accurately predicts chemical potential and equation of state.

Matches well with quantum Monte Carlo calculations.

Shows the evolution of atomic correlations during crossover.

Abstract

We present a mean field approach based on pairs of fermionic atoms to describe condensates in the BEC-BCS crossover regime. By introducing an effective potential, the mean field equation allows us to calculate the chemical potential, the equation of states and the atomic correlation function. The results agree surprisingly well with recent quantum Monte Carlo calculations. We show that the smooth crossover from the bosonic mean field repulsion between molecules to the Fermi pressure among atoms is associated with the evolution of the atomic correlation function.