Pair creation and axial anomaly in light-cone $QED_2$

TL;DR

This paper provides an exact solution to the 1+1 dimensional massive Dirac equation in light-cone coordinates with an arbitrary electric field, analyzing pair production, currents, and the axial anomaly, revealing a potential phase transition.

Contribution

It offers an exact solution to the Dirac equation in light-cone coordinates with an arbitrary electric field and explores the axial anomaly and phase transition phenomena.

Findings

Exact solution to Dirac equation in light-cone coordinates

Calculation of pair production rate in electric field

Observation of a possible phase transition at infinite L

Abstract

The 1+1 dimensional massive Dirac equation is solved exactly in light-cone coordinates for $x^+ > 0$ and $x^- > -L$, in the presence of an arbitrary $x^+$ dependent electric field. Our solution resolves the ambiguity at $p^+ = 0$. We also obtain the one loop rate for pair production for a positive electric field, compute the expectation values of the vector and axial vector currents, and recover the well known anomaly $e^2 E/\pi$ in the divergence of the latter. A final intriguing result is that the theory seems to exhibit a phase transition in the limit of infinite $L$.