Intrinsic Nonlocality of Spin- and Polarization-Resolved Probabilities in Strong-Field Quantum Electrodynamics
This paper demonstrates that standard strong-field QED models fail to accurately predict angle-, spin-, and polarization-resolved distributions because they incorrectly treat photon emission as an instantaneous local event, and it proposes a new physically consistent model that integrates over the finite formation region to reveal significant deviations in polarization and helicity patterns with major implications for both laboratory experiments and astrophysical observations.