On two-color QCD with baryon chemical potential

TL;DR

This paper investigates SU(2) QCD with multiple flavors at finite baryon chemical potential, demonstrating diquark condensation and baryon superconductivity, and deriving the effective Lagrangian for low-energy excitations.

Contribution

It provides a rigorous proof of diquark condensation at finite mu and derives the effective Lagrangian for low-lying states using extended chiral symmetry.

Findings

Diquark condensation occurs at finite baryon chemical potential.

Baryon superconductivity results from symmetry breaking.

Exact determination of mass dependence on chemical potential.

Abstract

We study SU(2) color QCD with even number of quark flavors. First, using QCD inequalities we show that at finite baryon chemical potential mu, condensation must occur in the channel with scalar diquark quantum numbers. This breaks the U(1) symmetry generated by baryon charge (baryon superconductivity). Then we derive the effective Lagrangian describing low lying meson and baryon excitations using extended local chiral symmetry of the theory. This enables us to determine the leading term in the dependence of the masses on mu exactly.