Nahm's equations, $N=1^*$ domain walls, and D-strings in $AdS_5 x S_5$
C. Bachas, J. Hoppe, B. Pioline
TL;DR
This work shows that BPS domain walls in the ${ m N}=1^*$ deformation and D-strings in $AdS_5 imes S^5$ are governed by Nahm equations with Kronheimer boundary conditions, linking field-theoretic vacua to brane constructions. The moduli spaces of walls are described as intersections ${ m N}( ho_-)\cap{ m S}( ho_+)$ of nilpotent orbits with shifted centralizers, yielding an additivity rule for wall dimensions and a clear notion of elementary walls. The radial D-strings furnish a holographic realization where fuzzy-sphere configurations correspond to higher-representation Wilson--'t Hooft lines, and kink transitions along the D-string worldsheet act as braiding operators in the dual CFT. The results provide a robust, index-theoretic framework for counting moduli and shed light on the nonperturbative vacuum structure, with potential implications for holography and matrix-model dynamics.
Abstract
We consider the following two problems: classical domain walls in the $N=1^*$ mass deformation of the maximally supersymmetric Yang Mills theory, and D-strings as external magnetic sources in the context of the AdS/CFT correspondence. We show that they are both described by Nahm's equations with unconventional boundary conditions, and analyze the relevant moduli space of solutions. We argue that general `fuzzy sphere' configurations of D-strings in AdS$_5$ correspond to Wilson-'t Hooft lines in higher representations of the dual SU(n) gauge theory.
