Quantum Phase Transition in the BCS-to-BEC Evolution of p-wave Fermi Gases

TL;DR

This paper explores a quantum phase transition in ultra-cold p-wave Fermi gases, revealing non-analytic behaviors in physical properties as the system transitions between BCS and BEC regimes.

Contribution

It demonstrates the existence of a quantum phase transition characterized by non-analyticities in compressibility, spin susceptibility, and superfluid density in p-wave Fermi gases.

Findings

Non-analyticity in compressibility and spin susceptibility at the transition

Massive rearrangement of momentum distribution in the ground state

Dramatic change in superfluid density behavior at critical point

Abstract

We discuss the possibility of a quantum phase transition in ultra-cold spin-polarized Fermi gases which exhibit a p-wave Feshbach resonance. We show that when fermionic atoms form a condensate that can be externally tuned between the BCS and BEC limits, the zero temperature compressibility and the spin susceptibility of the fermionic gas are non-analytic functions of the two-body bound state energy. This non-analyticity is due to a massive rearrangement of the momentum distribution in the ground state of the system. Furthermore, we show that the low temperature superfluid density is also non-analytic, and exhibits a dramatic change in behavior when the critical value of the bound state energy is crossed.