Instanton Effects in ABJM Theory from Fermi Gas Approach

TL;DR

This paper analyzes non-perturbative instanton effects in the ABJM theory's partition function using the Fermi gas approach, deriving exact results and proposing an analytical expression for leading D2-instanton corrections expressed via Airy functions.

Contribution

It provides the first detailed computation of instanton effects in ABJM theory using the Fermi gas formalism, including exact partition function values and an analytical form for D2-instanton corrections.

Findings

Exact partition functions computed for specific levels and N values.

Non-perturbative corrections extracted and fitted to expected forms.

Analytical expression for leading D2-instanton correction proposed.

Abstract

We study the instanton effects of the ABJM partition function using the Fermi gas formalism. We compute the exact values of the partition function at the Chern-Simons levels k=1,2,3,4,6 up to N=44,20,18,16,14 respectively, and extract non-perturbative corrections from these exact results. Fitting the resulting non-perturbative corrections by their expected forms from the Fermi gas, we determine unknown parameters in them. After separating the oscillating behavior of the grand potential, which originates in the periodicity of the grand partition function, and the worldsheet instanton contribution, which is computed from the topological string theory, we succeed in proposing an analytical expression for the leading D2-instanton correction. Just as the perturbative result, the instanton corrections to the partition function are expressed in terms of the Airy function.