Frequency Chirp-Induced Enhancement of Electron-Positron Pair Production in Polarized Laser Fields

We investigate electron-positron pair production in frequency-chirped, polarized laser fields using the Dirac-Heisenberg-Wigner formalism. A key theoretical finding is the polarization-dependent critical chirp threshold b c ( δ ), which marks the transition between tunneling-dominated and multi-photon pair production regimes: b c doubles as polarization evolves from linear ( δ = 0, b c (0) = 0.02 m 2 ) to circular ( δ = 1, b c (1) = 0.04 m 2 ). Above this threshold, chirp induces spectral compression with the momentum distribution width scaling as △ q ∝ b -1/2 , concentrating pairs into a smaller phase-space volume and enhancing production yields by up to three orders of magnitude, following the universal scaling law n ∝ ( bτ ) 3/2 . Notably, non-monotonic polarization dependence is observed at intermediate chirp values, where linear polarization temporarily surpasses circular in yield before convergence at large b . These results establish chirp as a precise control parameter for optimizing EP pair production in nonperturbative quantum electrodynamics, advancing the theoretical framework for understanding quantum vacuum dynamics and providing a foundation for structured pulse engineering in strong-field quantum electrodynamics.