  We study domain walls and vortices in chiral symmetry breaking in a QCD-like
theory with N flavors in the chiral limit. If the axial anomaly is absent,
there exist stable Abelian axial vortices winding around the spontaneously
broken U(1)_A symmetry and non-Abelian axial vortices winding around both the
U(1)_A and non-Abelian SU(N) chiral symmetries. In the presence of the axial
anomaly term, metastable domain walls are present and Abelian axial vortices
must be attached by N domain walls, forming domain wall junctions. We show that
a domain wall junction decays into N non-Abelian vortices attached by domain
walls, implying its metastability. We also show that domain walls decay through
the quantum tunneling by creating a hole bounded by a closed non-Abelian
vortex.
