Complete Wetting in Supersymmetric QCD or Why QCD Strings Can End on Domain Walls

TL;DR

This paper explains how QCD strings can end on domain walls using effective field theories in supersymmetric QCD, showing that domain walls are wet by deconfined phases, allowing strings to terminate at low temperatures.

Contribution

It provides a field-theoretic explanation for QCD string termination on domain walls, connecting supersymmetric QCD phenomena with M-theory insights.

Findings

Domain walls are wet by deconfined phases at high temperatures.

Polyakov loop expectation value is non-zero on the domain wall.

QCD strings can end on domain walls due to finite free energy at the wall.

Abstract

As argued by Witten on the basis of M-theory, QCD strings can end on domain walls. We present an explanation of this effect in the framework of effective field theories for the Polyakov loop and the gluino condensate in N=1 supersymmetric QCD. The domain walls separating confined phases with different values of the gluino condensate are completely wet by a layer of deconfined phase at the high-temperature phase transition. As a consequence, even at low temperatures, the Polyakov loop has a non-vanishing expectation value on the domain wall. Thus, close to the wall, the free energy of a static quark is finite and the string emanating from it can end on the wall.