This morning, I read an interesting report from Berkeley Labs about the development of metamaterials to create a nonlinear dynamic system that could potentially enable efficient quantum computing. Once I scooped my brains up off the floor and shoved them back into my head, I started making sense of that story.
First, let's talk about metamaterials. In nature, we expect the stuff we encounter to behave in specific ways depending upon what it's made of. For example, we'd expect that wood will burn if thrown on a fire, or that diamonds will cut glass if you file them down into points. But metamaterials include stuff that we engineer ourselves. This stuff behaves according to its physical structure, not what it's made of.
A metamaterial's microscopic structure usually has several different types of molecules arranged in a repeating pattern. Creating specific types of microstructures results in different behaviors, ranging from how the material interacts with light or sound or even seismic motion. In the case of the Berkeley Labs story, the metamaterial in question allows light to travel through it in an interesting way.
In the nonlinear side of things, the particular effect the Berkeley Labs metamaterial expressed was to strengthen light waves in every direction as light passed through the metamaterial. According to the researchers, this could make the metamaterial useful in light sources and quantum computing.
So what is quantum computing? Your classic computer operates based on the input of a bunch of digital switches set to either 0 or 1 (or off and on if you prefer). We call them bits -- a bit is either a 0 or a 1. A quantum computer relies on quantum bits or qubits. A qubit encompasses both 0 and 1 (and technically all states between the two) at the same time.
For some computer problems, a quantum computer would be a huge leap from classical machines. For example, the traveling salesman problem. That's the one where you start off with a series of cities that a salesman has to pass through and it's your job to find the most efficient route. In a classic computer system, the computer would need to complete every possible variation and then compare the results at the end. That takes lots of time.
With a quantum computer, the qubits could allow the machine to make simultaneous calculations, assigning each result a probability of it being the most efficient route. It takes much less time than the classic approach, though you end up with an answer that's "only" probably right (that probably can approach certainty with a high enough degree of confidence).
The metamaterials in the Berkeley Labs experiment could help scientists create entangled photons -- the basic particles of light. Entanglement is another odd quantum phenomena where two subatomic particles behave in a specific way relative to one another, even if the two particles are separated by vast differences. One of the big challenges to creating reliable quantum computers is making a system that doesn't break down the moment you try to interact with it. This new method for generating entangled photons could help quantum engineers experiment with different approaches to creating a truly powerful quantum computer.
It's all very exciting stuff. And now, if you'll excuse me, I will return to shoving my brains back into place.