Black holes put pressure on their environment

Physicists at the University of Sussex have discovered that black holes put pressure on their environment, a scientific first.

In 1974, Stephen Hawking made the fundamental discovery that black holes emit thermal radiation. Before that, black holes were considered inert, the final stages of a dying heavy star.

Scientists at the University of Sussex have shown that these are in fact even more complex thermodynamic systems, with not only temperature but also pressure.

The fortuitous discovery was made by Professor Xavier Calmet and Folkert Kuipers of the Department of Physics and Astronomy at the University of Sussex, and is published today in Physical examination D.

Calmet and Kuipers were puzzled by an additional number that presented in the equations that they applied quantum gravitational corrections to the entropy of a black hole.

During a discussion of this curious outcome on Christmas Day 2020, the realization that what they were seeing behaved like pressure emerged. After further calculations, they confirmed their exciting discovery that quantum gravity can cause pressure in black holes.

Xavier Calmet, professor of physics at the University of Sussex, said: “Our discovery that the Schwarzschild black holes have pressure as well as temperature is even more exciting given that it was a total surprise. delighted that the research we are undertaking at the University of Sussex in quantum gravity has given the scientific community a better understanding of the nature of black holes.

“Hawking’s historical intuition that black holes are not black but have a radiation spectrum very similar to that of a black body makes black holes an ideal laboratory for studying the interaction between quantum mechanics and gravity. and thermodynamics.

“If you consider black holes only in general relativity, we can show that they have a singularity in their centers where the laws of physics as we know them must collapse. It is hoped that when quantum field theory will be incorporated into general relativity, we may be able to find a new description of black holes.

“Our work is a step in this direction, and although the pressure exerted by the black hole we are studying is minimal, the fact that it is present opens up multiple new possibilities, covering the study of astrophysics, particle physics and quantum physics. “

Folkert Kuipers, a doctoral student in the School of Mathematical and Physical Sciences at the University of Sussex, said: “It is exciting to work on a discovery that improves our understanding of black holes, especially as a student researcher.

“The moment we realized that the mysterious result of our equations was telling us that the black hole we were studying was under pressure – after months of struggling with it – was exhilarating.

“Our result is a consequence of the cutting edge research we are conducting in quantum physics at the University of Sussex and it sheds new light on the quantum nature of black holes.”