Simulating fermion production in 1+1 dimensional QED

TL;DR

This paper uses real-time lattice simulations to study fermion-antifermion pair production in 1+1 dimensional QED, revealing non-perturbative dynamics, backreaction effects, and the formation of a linear potential between produced pairs.

Contribution

It introduces a lattice generalization of the Dirac-Heisenberg-Wigner function and demonstrates accurate non-perturbative simulation of fermion production including backreaction effects.

Findings

Recovery of the Schwinger formula in 1+1D

Observation of field decay due to pair backreaction

Identification of a linear potential between fermion bunches

Abstract

We investigate fermion--anti-fermion production in 1+1 dimensional QED using real-time lattice techniques. In this non-perturbative approach the full quantum dynamics of fermions is included while the gauge field dynamics can be accurately represented by classical-statistical simulations for relevant field strengths. We compute the non-equilibrium time evolution of gauge invariant correlation functions implementing 'low-cost' Wilson fermions. Introducing a lattice generalization of the Dirac-Heisenberg-Wigner function, we recover the Schwinger formula in 1+1 dimensions in the limit of a static background field. We discuss the decay of the field due to the backreaction of the created fermion--anti-fermion pairs and apply the approach to strongly inhomogeneous gauge fields. The latter allows us to discuss the striking phenomenon of a linear rising potential building up between produced fermion bunches after the initial electric pulse ceased.