The same researchers who used exotic substances called metamaterials to make a benchtop Big Bang have mimicked the end of time, also known as the Big Crunch.
Light traveling through metamaterials is described mathematically by equations used to describe space and time, allowing physicists to probe cosmic questions in a controlled manner.
In this experiment, the photons underwent a “higher harmonic generation,” or a sudden rise in frequency and energy. Put another way, “the end of time looks very hot,” said electrical engineer Igor Smolyaninov of the University of Maryland.
Smolyaninov and colleagues Ehren Hwang and Evgenii Narimanov wanted to probe the Big Crunch, a postulated scenario in which the universe contracts back upon itself, eventually collapsing into a black hole.
As described July 20 on the physics preprint website arXiv, their metamaterial consisted of a plastic called polymethyl methacrylate embedded in a grid upon gold film.
As photon-electron waves called plasmons flowed through the gold they followed the rules of a universe with two dimensions of space and one of time, said Smolyaninov. Flowing through the plastic, they followed the rules of a universe with one dimension of space and two of time.
When the substances are placed perpendicular to each other, as on this grid, then a dimension of time runs up against a dimension of space. As plasmons excited by a beam of laser light coursed through the plastic and hit the gold, time effectively came to an end.
Plasmons diverged at that boundary, their photons rising in energy in accordance with predictions.
In future studies Smolyaninov plans to add quantum dot semiconductors to the metamaterial, which he says would allow it to better simulate the center of a black hole.
There he hopes to find an analogue for Hawking radiation, a quantum phenomenon predicted by Stephen Hawking to exist at the edge of black holes.
“Normally, if you have a black hole and a particle near the event horizon, that’s the end of the story. But according to Hawking radiation, one particle is absorbed and another let out. In classical physics, this is forbidden, but in quantum physics it’s allowed,” said Smolyaninov. “Black holes don’t just absorb everything.”