Using cutting-edge computational modeling, scientists from the University of Oxford, in collaboration with the Instituto Superior Técnico at the University of Lisbon, have successfully produced the first real-time, three-dimensional simulations showing how powerful laser beams can modify the “quantum vacuum.”

Once thought to be completely empty, this vacuum is now understood through quantum physics to be filled with fleeting pairs of virtual electrons and positrons.

The team’s simulations vividly capture a strange and long-theorized effect in quantum physics called vacuum four-wave mixing. According to this phenomenon, when three laser pulses are precisely focused, their combined electromagnetic fields can polarize the virtual particles within the vacuum.

This interaction causes photons to scatter off one another like billiard balls, resulting in the creation of a fourth beam of light in what researchers describe as a “light from darkness” process. These simulated events may provide a new way to explore untested areas of physics at extremely high energy levels.

“This is not just an academic curiosity—it is a major step toward experimental confirmation of quantum effects that until now have been mostly theoretical,” said study co-author Professor Peter Norreys, Department of Physics, University of Oxford.

A New Era of Ultra-Intense Lasers
The work arrives just in time as a new generation of ultra-powerful lasers starts to come online. Facilities such as the UK’s Vulcan 20-20, the European ‘Extreme Light Infrastructure (ELI)’ project, and China’s Station for Extreme Light (SEL) and SHINE facilities are set to deliver power levels high enough to potentially confirm photon-photon scattering in the lab for the first time. Photon-photon scattering has already been selected as one of three flagship experiments at the University of Rochester’s OPAL dual-beam 25 PW laser facility in the United States.

The simulations were carried out using an advanced version of OSIRIS, a simulation software package that models interactions between laser beams and matter or plasma.