Color Superfluidity and "Baryon" Formation in Ultracold Fermions

TL;DR

This paper explores phase transitions in ultracold fermionic atoms with three internal states, revealing color superfluidity and baryon-like trion formation, providing insights into quantum field theory analogies.

Contribution

It introduces a variational approach to identify superfluid and trion phases in three-color fermionic systems, highlighting their analogy to QCD phenomena.

Findings

Color superfluid state emerges for small attractive interactions.

Triplet fermions ('trions') form at stronger interactions.

Transition between phases is second order.

Abstract

We study fermionic atoms of three different internal quantum states (colors) in an optical lattice, which are interacting through attractive on site interactions, U<0. Using a variational calculation for equal color densities and small couplings, |U| < |U_C|, a color superfluid state emerges with a tendency to domain formation. For |U| > |U_C|, triplets of atoms with different colors form singlet fermions (trions). These phases are the analogies of the color superconducting and baryonic phases in QCD. In ultracold fermions, this transition is found to be of second order. Our results demonstrate that quantum simulations with ultracold gases may shed light on outstanding problems in quantum field theory.