Soft-Radiation-Induced Decoherence of Heavy-Quark Spin Entanglement at the Electron-Ion Collider
The paper investigates how unresolved gluon radiation causes decoherence in heavy-quark spin correlations produced by polarized photons in deep-inelastic scattering. It finds that while normal-axis spin correlations are protected, in-plane coherences are exponentially suppressed by a factor related to the unresolved soft energy. This mechanism is linked to stochastic rotations of the spin correlation plane induced by subleading soft recoil.