Scientists at the University of Oxford have simulated a way to summon light, seemingly out of thin air. Their work is quite exciting as it taps into one of the strangest predictions of quantum physics, which is that empty space isn’t really empty.
Using powerful computer simulations, the team recreated an elusive phenomenon where intense laser beams disturb the so-called quantum vacuum, giving rise to real, observable effects like the creation of light without any atoms, dust, or physical matter.
This achievement suggests that in the vast emptiness of space, there’s a hidden dance of particles that we can’t see or touch. Moreover, it represents the first step toward manipulating the vacuum itself.
The study authors claim that this could have wide-reaching implications for high-energy physics, advanced laser systems, and our understanding of reality.
Making light from nothing
To understand what the researchers achieved, you first have to forget what you think you know about a vacuum. In classical physics, a vacuum is just an empty box—no air, no particles, no light.
However, quantum physics says otherwise. Even the emptiest space is alive with fleeting virtual particles, especially pairs of electrons and positrons that flicker in and out of existence in mere moments. “The quantum vacuum is filled with energy fluctuations from which virtual electron-positron pairs arise,” the study authors note.
These pairs are usually unobservable, but under the right conditions, they can interact with real energy and show themselves. That’s exactly what the researchers tried to simulate. They used a high-powered program called OSIRIS to run advanced 3D simulations; think of it as a virtual lab where the rules of quantum physics play out in detail.
Their goal was to recreate a theoretical phenomenon called vacuum four-wave mixing. Here’s how it works: when multiple beams of laser light (three in this case) crisscross in a vacuum, the virtual particles in that space can become polarized by the intense energy. This polarization allows the laser beams to mix and form new light waves, even though no material was added. It’s as if new light was born from a field of invisible, flickering particles.
The simulation featured petawatt-level lasers, which are some of the most powerful beams ever imagined. A petawatt is a million billion watts, or roughly the combined power of ten trillion light bulbs. Although the researchers didn’t fire real lasers in a lab, they ran detailed simulations that showed what would happen if they did, and what they found was stunning.
The laser beams could, through the quantum vacuum, change direction, mix, and even create new light—something that has never been seen directly before. Another interesting outcome was vacuum birefringence. In regular optics, birefringence happens when light bends or splits while passing through a crystal.
However, in this case, the crystal was just the vacuum itself, distorted by laser energy. The light’s polarization changed because the virtual particles (electrons and positrons) were being stretched and rotated by the intense fields. This bizarre optical effect (vacuum birefringence) was predicted decades ago but had never been demonstrated, even in simulations, until now.
Emptiness might explain many mysterious concepts
If successful in physical experiments, the current research work could help scientists study physics beyond the Standard Model, including the nature of dark energy, the structure of spacetime, and how light and matter interact at extreme energies. It might even lead to technologies that control light with unprecedented precision.
However, the quantum effects simulated here are incredibly delicate and difficult to observe in a noisy lab environment. Plus, the researchers are talking about lasers that are so powerful they could vaporize most materials, so it would take some time before scientists figure out a suitable setup to conduct such experiments.
That’s what makes simulations like this so valuable. They help scientists narrow down the exact conditions needed before committing to expensive, high-risk experiments.
The study authors now hope to apply their virtual approach to explore more exotic pulse shapes and laser beam patterns. Their simulations will act as a roadmap for upcoming experiments and, maybe, help us learn how to turn nothing in space into something, starting with a beam of light.
The study is published in the journal Communications Physics.