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Main Authors: Filoche, Baptiste, Hohenegger, Stefan, Kimura, Taro
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.20674
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author Filoche, Baptiste
Hohenegger, Stefan
Kimura, Taro
author_facet Filoche, Baptiste
Hohenegger, Stefan
Kimura, Taro
contents We study the instanton counting in four dimensional $\mathcal{N}=2$ supersymmetric gauge theories on the blow-up of $\mathbb{C}^2$: we start by formulating the instanton moduli space as a quiver variety, which we regularise by introducing two stability parameters, thus endowing it with a structure of infinitely many chambers separated by walls. Within a given chamber, we formulate the instanton partition function as a contour integral, which can be evaluated using the Jeffrey-Kirwan residue prescription. We characterise the physically relevant contributions in terms of bipartite oriented graphs and show that they can more efficiently be classified in terms of combinatorial objects called super-partitions. Within a given chamber, only certain types of super-partitions contribute and we show that the corresponding selection criteria are equivalent to stability conditions that have previously been proposed in the literature. We use this formalism to compare how the instanton counting changes when moving across walls between neighbouring chambers and provide explicit expressions for the corresponding partition functions. In a limiting chamber and using our approach, we show how to reproduce the Nakajima-Yoshioka blow-up formula.
format Preprint
id arxiv_https___arxiv_org_abs_2604_20674
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Wall-crossing of Instantons on the Blow-up
Filoche, Baptiste
Hohenegger, Stefan
Kimura, Taro
High Energy Physics - Theory
Mathematical Physics
Algebraic Geometry
We study the instanton counting in four dimensional $\mathcal{N}=2$ supersymmetric gauge theories on the blow-up of $\mathbb{C}^2$: we start by formulating the instanton moduli space as a quiver variety, which we regularise by introducing two stability parameters, thus endowing it with a structure of infinitely many chambers separated by walls. Within a given chamber, we formulate the instanton partition function as a contour integral, which can be evaluated using the Jeffrey-Kirwan residue prescription. We characterise the physically relevant contributions in terms of bipartite oriented graphs and show that they can more efficiently be classified in terms of combinatorial objects called super-partitions. Within a given chamber, only certain types of super-partitions contribute and we show that the corresponding selection criteria are equivalent to stability conditions that have previously been proposed in the literature. We use this formalism to compare how the instanton counting changes when moving across walls between neighbouring chambers and provide explicit expressions for the corresponding partition functions. In a limiting chamber and using our approach, we show how to reproduce the Nakajima-Yoshioka blow-up formula.
title Wall-crossing of Instantons on the Blow-up
topic High Energy Physics - Theory
Mathematical Physics
Algebraic Geometry
url https://arxiv.org/abs/2604.20674