Speaker
Description
Entanglement generated in the early stage of relativistic heavy-ion collisions (HIC) is considered a direct and fundamental source for understanding fast thermalization, entropy production, and evolution. Spin entanglement in QCD, arising from non-commutative geometric effects of quantum fields, provides a new avenue to explore the quantum informational footprint of the QCD topological vacuum structure and reveal potential origin of thermal entropy in chromodynamics. This work studies spin entanglement among quarks originating from two main sources: instanton(sphaleron)-induced effects, and gluon–quark scattering. Innovatively, we provide a method to extract spin entanglement in scattering processes respectively for light and heavy quark sector that corresponds to the two sources. We systematically calculate the entanglement in both cases and present results including concurrence and entropy as functions of the instanton parameter, physical mass, and momentum scale—aspects not explicitly discussed in previous studies. This directly reveals how the non-equilibrium nature of the system and field topology effects modulate spin entanglement, and clarifies the corresponding quantitative relationship between entanglement measures and core physical information related to flavor and scale. More importantly, this quantitatively explains the well-know sphaleron effect on QGP formation in early stage and its fast thermalization from spin d.o.f.
We further interpret the entanglement time scale, providing a quantitative comparison with the scrambling time, and clarify the quantum informational relations in the early-stage thermalization. Finally, we discuss some recent experimental interests and results in high-energy collisions.
