Quantum effects prevent the formation of black holes from high concentrations of intense light, say physicists

Over the past seventy years, astrophysicists have theorized about the existence of “ball lightning,” which are black holes created by extremely high concentrations of light.

They speculated that these special black holes might be linked to astronomical phenomena such as dark matter and that they could even serve as a source of energy for hypothetical spacecraft engines in the distant future.

However, new theoretical physics research by a team of researchers from the University of Waterloo and the Universidad Complutense de Madrid shows that ball lightning is impossible in our current universe. Their research, titled “No black holes made of light,” was presented at the arXiv Preprint server and will be published shortly Physical Examination Letters.

“The most common black holes known are those formed by enormous concentrations of normal matter collapsing under their own gravity,” said Eduardo Martín-Martínez, professor of applied mathematics and mathematical physics and member of the Perimeter Institute for Theoretical Physics.

“Since in Einstein’s general theory of relativity any kind of energy curves spacetime, it has long been speculated that an enormous concentration of energy in the form of light could lead to a similar collapse. However, this prediction was made without taking quantum effects into account.”

The team created a mathematical model that took quantum effects into account and showed that the concentration of light required to create ball lightning is dozens of orders of magnitude higher than the concentration observed in quasars, the brightest objects in our universe.

“Long before you could reach that intensity of light, certain quantum effects would first occur,” said José Polo-Gómez, a doctoral student in applied mathematics and quantum information. “Such a strong concentration of light would lead to the spontaneous creation of particles such as electron-positron pairs, which would move away from the area very quickly.”

Although the conditions necessary to achieve such an effect cannot be tested on Earth with current technology, the team can be confident in the accuracy of their predictions because they are based on the same mathematical and scientific principles as positron emission tomography (PET).

“To understand this phenomenon, one can think of the annihilation of matter and antimatter, as occurs in PET scans. Electrons and their antiparticles (positrons) can annihilate each other and decay into pairs of photons, or light particles,” said Martín-Martínez.

“Our results are a consequence of the phenomenon of vacuum polarization and the Schwinger effect. Explaining them in a few words can be challenging, but it is helpful to think about it: The phenomenon we predicted that would prevent the formation of black holes from light is in many ways the opposite of the matter-antimatter decay phenomenon seen in a PET scan. Given a large concentration of photons, these can decay into electron-positron pairs that are quickly scattered away, taking the energy with them and preventing gravitational collapse.”

While the impossibility of ball lightning may be disappointing for astrophysicists, the discovery is an important achievement in the kind of fundamental physics research made possible by the partnership between applied mathematics, the Perimeter Institute and the Institute for Quantum Computing in Waterloo.

“Although these discoveries may not have applications today, we are laying the foundation for the technological innovations of our descendants,” Polo-Gómez said. “The science behind PET scanning machines was once purely theoretical, and today there is one in every hospital.”