  Gauge fields provide the fundamental interactions in the Standard Model of
particle physics. Gauge field configurations with nontrivial topological
windings are known to play crucial roles in many important phenomena, from
matter-anti-matter asymmetry of today's universe to spontaneous chiral symmetry
breaking in strong interaction. Their presence is however elusive for direct
detection in experiments. Here we show that measurements of the chiral magnetic
effect (CME) in heavy ion collisions can be used for accessing the topological
fluctuations of the non-Abelian gauge fields in the Quantum Chromodynamics
(QCD). To achieve this, we implemented a key ingredient, the stochastic
dynamics of gauge field topological fluctuations, into a state-of-the-art
framework for simulating the CME in these collisions. This new framework
provides the necessary tool to quantify initial topological fluctuations from
any definitive CME signal to be extracted from experimental data. It also
reveals a universal scaling relation between initial topological fluctuations
and particle multiplicity produced in the corresponding collision events.
