Nonlinear propagation of light in Dirac matter

TL;DR

This paper models the nonlinear propagation of intense laser light in quantum plasmas using a Dirac-Maxwell framework, revealing relativistic and spin effects that influence wave frequency shifts, with implications for dense astrophysical plasmas.

Contribution

It introduces a coupled Dirac and Maxwell model to analyze relativistic and spin effects on laser propagation in quantum plasmas, including potential astrophysical applications.

Findings

Relativistic effects cause a downshift in laser frequency.

Electron spin-1/2 effects can cause frequency up- or downshifts.

Spin effects are small in laboratory plasmas but significant in super-dense stellar cores.

Abstract

The nonlinear interaction between intense laser light and a quantum plasma is modeled by a collective Dirac equation coupled with the Maxwell equations. The model is used to study the nonlinear propagation of relativistically intense laser light in a quantum plasma including the electron spin-1/2 effect. The relativistic effects due to the high-intensity laser light lead, in general, to a downshift of the laser frequency, similar to a classical plasma where the relativistic mass increase leads to self-induced transparency of laser light and other associated effects. The electron spin-1/2 effects lead to a frequency up- or downshift of the electromagnetic (EM) wave, depending on the spin state of the plasma and the polarization of the EM wave. For laboratory solid density plasmas, the spin-1/2 effects on the propagation of light are small, but they may be significant in super-dense plasma in the core of white dwarf stars. We also discuss extensions of the model to include kinetic effects of a distribution of the electrons on the nonlinear propagation of EM waves in a quantum plasma.