Nonperturbative QED vacuum birefringence

TL;DR

This paper presents a nonperturbative calculation of QED vacuum birefringence under extremely strong magnetic fields, extending perturbative predictions to astrophysical scenarios like pulsars and magnetars.

Contribution

It introduces a nonperturbative approach to calculate vacuum birefringence in strong magnetic fields, surpassing the limitations of perturbative methods.

Findings

Vacuum birefringence persists at magnetic fields exceeding the Sauter-Schwinger limit.

Perturbative QED predictions can be extended to astrophysical magnetic fields.

Implications for pulsar and magnetar observations are discussed.

Abstract

In this paper we represent nonperturbative calculation for one-loop Quantum Electrodynamics (QED) vacuum birefringence in presence of strong magnetic field. The dispersion relations for electromagnetic wave propagating in strong magnetic field point to retention of vacuum birefringence even in case when the field strength greatly exceeds Sauter-Schwinger limit. This gives a possibility to extend some predictions of perturbative QED such as electromagnetic waves delay in pulsars neighbourhood or wave polarization state changing (tested in PVLAS) to arbitrary magnetic field values. Such expansion is especially important in astrophysics because magnetic fields of some pulsars and magnetars greatly exceed quantum magnetic field limit, so the estimates of perturbative QED effects in this case require clarification.