Technology Review | The Physics arXiv Blog | kfc | 2011 July 26
Ever wondered what would happen if the dimension of time came to a sudden end? A new experiment reveals all.
One of the most exciting areas of science is the emerging field of spacetime analogues. This is the discipline in which physicists play around with systems that have a formal mathematical link with general relativity.
For example, changes in the way electrons move in graphene as it is cooled are identical to the changes that may have occurred in the universe soon after the big bang. So physicists can use cool graph to test theories about the universe's earliest behaviour.
Another example is the formal mathematical analogy between the behaviour of light in electromagnetic space and in spacetime. That's interesting because physicists have recently learnt how to manipulate electromagnetic space using metamaterials. That has allowed them to create the electromagnetic equivalents of quantum foam, the big bang and even the entire multiverse.
All of these experiments are jaw droppers (imagine making black hole in the lab). That's why it's hard to top them.
But Igor Smolyaninov at the University of Maryland likes to have a go. Today, he explains how he's created an experiment that models the end of time.
The idea is straightforward (no really!). Metamaterials can be made to behave like ordinary space with two dimensions of space and one of time. But they can also be made to behave like other types of spaces, with two dimensions of time and one of space, for example.
Smolyaninov points out that an interesting situation occurs when these two materials are place end on. If a time dimension is perpendicular to a space dimension, it simply hits a dead end. In other words, time runs out.
"This situation (which cannot be realized in classic general relativity) may be called the "end of time"," he says in a paper with a couple of colleagues.
Not content with merely thinking about such a scenario, these guys have gone ahead and built it using a plastic called polymethyl methacrylate or PMMA deposited in stripes onto gold film. The light takes the form of plasmons moving across the surface.
So what happens at the end of time? Smolyaninov says that the electromagnetic field simply diverges, which is something of an anticlimax in an experiment so pregnant with sci-fi potential.
But interesting stuff nevertheless.
Hyperbolic metamaterial interfaces: Hawking radiation from Rindler horizons and the "end of time"
- Igor I. Smolyaninov, Ehren Hwang, Evgenii Narimanov
arXiv.org > physics > arXiv:1107.4053 > 20 Jul 2011
The Big Crunch: Physicists Make Time End
Wired Science | Brandon Keim | 2011 July 28
This is the way the world ends: not with a bang but a higher harmonic generation.
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.”
That's one way to find out what the universe has been hiding, behind all this time.