Instanton Corrections for m and Omega

TL;DR

This paper investigates instanton corrections in N=2* gauge theory through string theory orbifold methods, computing deformed instanton partition functions and highlighting the universality of the deformation structure.

Contribution

It introduces a string theory approach to compute non-perturbative instanton effects and demonstrates the similarity to Omega-deformation, confirming a universal deformation structure.

Findings

Computed the deformed instanton partition function.

Established the similarity between the deformation and Omega-deformation.

Commented on physical realization of mass deformation via vertex operators.

Abstract

In this paper, we study instanton corrections in the N=2* gauge theory by using its description in string theory as a freely-acting orbifold. The latter is used to compute, using the worldsheet, the deformation of the Yang-Mills action. In addition, we calculate the deformed instanton partition function, thus extending the results to the non-perturbative sector of the gauge theory. As we point out, the structure of the deformation is extremely similar to the Omega-deformation, therefore confirming the universality of the construction. Finally, we comment on the realisation of the mass deformation using physical vertex operators by exploiting the equivalence between Scherk-Schwarz deformations and freely-acting orbifolds.