Diquark Bose-Einstein condensation at strong coupling

TL;DR

This paper explores how strong scalar diquark interactions in a QCD-inspired model lead to Bose-Einstein condensation of diquarks, resulting in a massless bound state and a new phase in the vacuum.

Contribution

It demonstrates the emergence of diquark Bose-Einstein condensation at strong coupling within the NJL model, revealing a novel phase transition mechanism.

Findings

Massless scalar diquark bound state appears at critical coupling

Bose condensation occurs in the vacuum due to strong diquark binding

Phase structure significantly altered by diquark coupling strength

Abstract

We investigate the phase structure of the $SU_f(2)\otimes SU_c(3)$ Nambu--Jona-Lasinio model as a function of the scalar diquark coupling strength. Above a critical coupling, the binding energy is sufficiently large to overcompensate the quark masses and a massless scalar diquark bound state emerges which leads to Bose condensation already in the vacuum.