| dc.description.abstract | Quiver gauge theories are widely studied in the context of AdS/CFT, which establishes a correspondence
between CFTs and string theories. CFTs in turn offer a map between quantum
states and Gauge Invariant Operators (GIOs). This thesis presents results on the counting and
correlators of holomorphic GIOs in quiver gauge theories with
flavour symmetries, in the zero coupling limit.
We first give a prescription to build a basis of holomorphic matrix invariants, labelled by
representation theory data. A fi nite N counting function of these GIOs is then given in terms
of Littlewood-Richardson coefficients. In the large N limit, the generating function simpli fies
to an in finite product of determinants, which depend only on the weighted adjacency matrix
associated with the quiver. The building block of this product has a counting interpretation
by itself, expressed in terms of words formed by partially commuting letters associated with
closed loops in the quiver. This is a new relation between counting problems in gauge theory
and the Cartier-Foata monoid. We compute the free fi eld two and three point functions of the
matrix invariants. These have a non-trivial dependence on the structure of the operators and
on the ranks of the gauge and flavour symmetries: our results are exact in the ranks, and their
expansions contain information beyond the planar limit.
We introduce a class of permutation centraliser algebras, which give a precise characterisation
of the minimal set of charges needed to distinguish arbitrary matrix invariants. For the
two-matrix model, the relevant non-commutative algebra is parametrised by two integers. Its
Wedderburn-Artin decomposition explains the counting of restricted Schur operators. The structure
of the algebra, notably its dimension, its centre and its maximally commuting sub-algebra,
is related to Littlewood-Richardson numbers for composing Young diagrams. | en_US |
