Giant Casimir Effect Is Predicted Inside Metamaterials
Exotic materials should lead to new ways of observing and playing with one
of the strangest effects in physics, say Chinese physicists.
Metamaterials are exotic substances designed to steer electromagnetic waves
in ways that are impossible with ordinary stuff. One of their more exciting
properties is that they can bend light in a way that is mathematically
equivalent to the way spacetime bends light.
This formal equivalence means that metamaterials can reproduce in the lab
the exact behaviour of light, not only in our spacetime, but in many others
that have only been conjectured until now. This allows physicists to use
metamaterials to simulate black holes, big bangs and even multiverses.
Today, Tian-Ming Zhao and Rong-Xin Miao at the University of Science and
Technology of China in Hefei use this kind of thinking to make a startling
prediction about the Casimir effect inside certain metamaterials.
The Casimir effect arises because our vacuum is filled with a maelstrom of
waves that leap in and out of existence at the smallest scales. The best
known consequence of this is the well known Casimir force, which pushes
together two conducting plates placed close together.
The explanation is that when the distance between the plates is small
enough, it can exclude any waves that are too big to fit in the gap. Since
there is nothing between the plates to oppose the effect of these waves,
they generate a force that pushes the plates together.
This Casimir force operates on a tiny scale, so small that it was only
measured for the first time in 1997. But it is not insignificant. At a
separation of 10nm, the force is equivalent to 1 atmosphere (although the
actual force depends on various factors such as the precise shape of the
objects in close proximity).
Of course, the properties of the vacuum waves depend strongly on the medium
in which they exist. So it's not hard to imagine that different spacetimes
might have a significant impact on the size of the Casimir effect.
This is exactly what Zhao and Miao show. They say that in a particular kind
of electromagnetic space called a Rindler space, the Casimir effect is
huge. The essential idea here is that the space can be designed to allow
only certain wavelengths to operate. If the electromagnetic properties of
the Rindler space are matched to the ambient temperature, then these kinds
of thermal waves can be made to dominate the Casimir energy.
That makes the Casimir energy huge. Zhao and Miao calculate that in a lab
at 300K (room temperature), the Casimir energy would be some 10^11 times
bigger than the free space value. That's a significant difference that
ought to make these effects accessible in an entirely new way to a much
broader audience.
Zhao and Miao also say that this kind of material ought to be relatively
straightforward to build, layer by layer.
What that means is that it won't be long before somebody builds this kind
of material and shows off the giant Casimir effect for the first time.
We'll be watching.
SEE:
http://arxiv.org/PS_cache/arxiv/pdf/1110/1110.1919v2.pdf
