Collective behavior of light in vacuum

TL;DR

This paper explores how light beams exhibit collective behaviors in vacuum due to light-by-light scattering, including polarization oscillations and wave-like amplitude propagation, which could be observed in future laser experiments.

Contribution

It reveals novel collective phenomena of light in vacuum, such as polarization oscillations and wave-like amplitude propagation, under specific initial conditions.

Findings

Polarization of counterpropagating beams oscillates periodically.

Amplitudes and intensities propagate as waves.

Potential observability in future laser experiments.

Abstract

Under the action of light-by-light scattering, light beams show collective behaviors in vacuum. For instance, in the case of two counterpropagating laser beams with specific initial helicity, the polarization of each beam oscillates periodically between the left and right helicity. Furthermore, the amplitudes and the corresponding intensities of each polarization propagate like waves. Such polarization waves might be observationally accessible in future laser experiments, in a physical regime complementary to those explored by particle accelerators.