Testing Hawking radiation in laboratory black hole analogues

Researchers at Weizmann Institute of Science and Cinvestav recently carried out a study testing the theory of Hawking radiation on laboratory analogues of black holes. In their experiments, they used light pulses in nonlinear fiber optics to establish artificial event horizons.

Back in 1974, renowned physicist Stephen Hawking amazed the physics world with his theory of Hawking radiation, which suggested that rather than being black, black holes should glow slightly due to quantum effects near the black hole's event horizon. According to Hawking's theory, the strong gravitational field around a black hole can affect the production of matching pairs of particles and anti-particles.

Should these particles be created just outside the event horizon, the positive member of this pair of particles could escape, resultinginan observed thermal radiation emitting from the black hole. This radiation, which was later termed Hawking radiation, would hence consist of photons, neutrinos and other subatomic particles. The theory of Hawking radiation was among the first to combine concepts from quantum mechanics with Albert Einstein's theory of General Relativity.

"I learned General Relativity in 1997 by lecturing a course, not by taking a course," Ulf Leonhardt, one of the researchers who carried out the recent study, told Phys.org. "This was a rather stressful experience where I was just a few weeks ahead of the students, but I really got to know General Relativity and fell in love with it. Fittingly, this also happened in Ulm, Einstein's birthplace. Since then, I have been looking for connections between my field of research, quantumopticsand General Relativity. My main goal is to demystify General Relativity. If, as I and others have shown, ordinary optical materials like glass act like curved spaces, then the curved space-time of General Relativity becomes something tangible, without losing its charm."

In collaboration with his first Ph.D. student Paul Piwnicki, Leonhardt put together some initial ideas of how to create optical black holes, which were published in 1999 and 2000. In 2004, he finally achieved a method that actually worked, which is the one used in his recent study.