We study the phase diagram of SU (N ) k gauge theory in three space-time dimensions coupled to two sets of fundamental fermions with masses m 1 and m 2 , respectively. The resulting twodimensional phase diagram shows a rich structure and widens in an interesting way previous results in the literature, to which it reduces in some limits. We present several checks of our proposal, including consistency with boson/fermion dualities.

Massive QCD at θ = π breaks CP spontaneously and admits domain walls whose dynamics and phases depend on the number of flavors and their masses. We discuss these issues within the Witten-Sakai-Sugimoto model of holographic QCD. Besides showing that this model reproduces all QCD expectations, we address two interesting claims in the literature. The first is about the possibility that the QCD domain-wall theory is fully captured by three-dimensional physics, only. The second regards the existence of quantum phases in certain Chern-Simons theories coupled to fundamental matter. Both claims are supported by the string theory construction. arXiv:1806.08292v3 [hep-th]