Universality of merons in non-Abelian gauge theories

TL;DR

This paper demonstrates that merons, fundamental non-Abelian topological solitons, are supported across various gauge theories and can lead to universal phenomena like spin from isospin, with implications for black holes and wormholes.

Contribution

It establishes the universality of merons in non-Abelian gauge theories beyond Yang--Mills and explores their gravitational and topological implications.

Findings

Merons are supported by a broad class of non-Abelian gauge theories.

Black holes and wormholes sourced by merons can be regularized within this framework.

Constructed a regular non-Abelian black hole solution based on a generalized nonlinear electrodynamics.

Abstract

Within the wide variety of topological solitons supported by Yang--Mills theory, merons occupy a particularly distinguished role. Despite their simplicity, they represent genuinely non-Abelian configurations that can be regarded as the fundamental building blocks of instantons, and they provide a qualitatively accurate picture of confinement. In this work, we show that such configurations are, in fact, supported by a broad class of non-Abelian gauge theories beyond Yang--Mills, provided that suitable physical conditions are satisfied, thereby rendering them universal. Taking into account their gravitational backreaction, we further demonstrate that both black holes and Euclidean wormholes sourced by merons admit natural extensions within this generalized framework, which regularizes the singular behavior they exhibit in constant--curvature backgrounds. As a byproduct, we construct a regular black hole solution supported by genuinely non-Abelian gauge fields, based on a non-Abelian generalization of the Ay\'on--Beato--Garc\'ia nonlinear electrodynamics. As a consequence of this universality, physical effects intrinsic to merons are likewise expected to be universal. A notable example is the spin from isospin effect, whereby bosonic excitations charged under the gauge group can effectively behave as fermionic degrees of freedom.