Holographic two dimensional QCD and Chern-Simons term

Understand

We present a holographic realization of large Nc massless QCD in two dimensions using a D2/D8 brane construction.

• The flavor axial anomaly is dual to a three dimensional Chern-Simons term which turns out to be of leading order, and it affects the meson spectrum and holographic renormalization in crucial ways.
• The massless flavor bosons that exist in the spectrum are found to decouple from the heavier mesons, in agreement with the general lore of non-Abelian bosonization.
• We also show that an external dynamical photon acquires a mass through the three dimensional Chern-Simons term as expected from the Schwinger mechanism.