Pair creation as a source of longitudinal chiral magnetoconductivity

Abstract

We demonstrate that chiral transport in a strongly magnetized electron-positron plasma can arise dynamically from dissipative pair-creation processes encoded in the imaginary part of the photon polarization tensor within one-loop finite-temperature quantum electrodynamics (QED). In the kinematic region corresponding to longitudinal photon absorption, real electron-positron pair production induces axial charge nonconservation and generates an electric current parallel to the magnetic field, without requiring the introduction of an external chiral chemical potential. This provides a microscopic mechanism for chiral magnetic transport, offering an alternative to hydrodynamic or anomaly-based effective descriptions in which chirality imbalance is typically introduced as an external input. We derive an explicit expression for the longitudinal magnetoconductivity associated with this process and show that it exhibits an approximately quadratic dependence on the magnetic field only within a restricted intermediate regime. This behavior emerges from the dominance of the lowest Landau levels as a characteristic of negative longitudinal magnetoresistance. We further analyze how Pauli blocking regulates the pair-creation phase-space and demonstrate that the dynamically generated chiral imbalance is suppressed at high frequencies, revealing a transition between chiral-active and non-chiral-active regimes. Our results connect microscopic QED processes with anomaly-related transport phenomena in strongly magnetized relativistic plasmas, where pair creation provides a dynamical source for chiral imbalance.