I will present recent developments on the impact of magnetic fields on the lowest topological cumulants using chiral perturbation theory, an effective theory of Quantum Chromodynamics that provides model-independent results at weak magnetic fields. In particular, I will discuss low energy theorems that connect the topological susceptibility and fourth cumulant to the chiral condensate and susceptibilities. Lattice QCD is an important tool to investigate these cumulants, not to mention the chiral condensate, the QCD phase diagram and thermodynamic observables. However, lattice QCD results are contaminated by finite volume corrections, which can be characterized using chiral perturbation theory since it encodes the long-range behavior of QCD. In the latter part of the talk, I will discuss recent developments on the nature of finite volume effects in background magnetic fields and (possibly) Euclidean electric fields.
Raza Sabbir Sufian, Manu Kurian