Instantons, finite N=2 Sp(N) theories and the AdS/CFT correspondence

TL;DR

This paper explores instanton solutions in N=2 Sp(N) gauge theories, connecting field theory, string theory, and the AdS/CFT correspondence, revealing how D-instantons behave in a specific geometric background.

Contribution

It demonstrates that the ADHM measure can be derived from field theory and D-instanton dynamics, and shows how large-N limits relate to the AdS_5 x S^5/Z_2 background.

Findings

ADHM measure can be obtained from field theory and D-instanton dynamics.

Large-N saddle-point approximation leads to AdS_5 x S^5/Z_2 background.

D-instantons fractionate at the singularity in the orbifold geometry.

Abstract

We examine ADHM multi-instantons in the conformal N=2 supersymmetric Sp(N) gauge theory with one anti-symmetric tensor and four fundamental hypermultiplets. We argue that the ADHM construction and measure can also be deduced from purely field theoretic considerations and also from the dynamics of D-instantons in the presence of D3-branes, D7-branes and an orientifold O7-plane. The measure then admits a large-N saddle-point approximation where the D3-branes disappear but the background is changed to AdS_5 x S^5/Z_2, as expected on the basis of the AdS/CFT correspondence. The large-N measure displays the fractionation of D-instantons at the singularity S^3 in S^5/Z_2 and is described for instanton number k by a certain O(k) matrix model.