Tuesday, 9 February 2010

A Snowball's Chance

Ah, I do love quantum physics. It's the strange scientific realm where everything is possible - and I do mean everything.
In the 'real world', if a ball bounces off a solid object or another ball, even if both of them are moving, we can say with certainty what will happen. Observe this same collision ten thousand times and every time the result will be the same - which is just as well if you're trying to learn how to play squash or pocket the eight-ball in pool.
Scale things down to the quantum level, however, and strange things start to happen. If we watch two particles colliding, for example, the outcome according to quantum physics becomes anything but certain and the predictability of conventional Newtonian science lets us down. Not only do things happen that we would expect to see happening, but things we wouldn't expect also happen, and occasionally things take place that seem completely impossible. In real-world terms, it would be like throwing a snowball at someone but having it turn aside in mid-air and miss the target. Or, even more bizarrely, flying straight back to smack you in the face.
Sounds insane, doesn't it? But these aren't the deranged ramblings of a mad theorist who ate too much cheese before settling down for the night; these are real, measurable effects.
At the quantum level of matter every outcome is possible, even the impossible ones, and if you watch for long enough you will see them actually happen. Thus it becomes impossible for us to say that in a given situation a particular outcome will occur; all we can do is quote the probability, or chance, of each concievable (and inconcievable) result.
This kind of thinking is weird and uncomfortable, so weird that even Einstein didn't like it and made his now famous assertion that "God does not play dice". Developments since then have shown, however, that God really does play dice - and He's very good at it.
One of the 'shouldn't-ever-happen-but-sometimes-does' effects that occur at the quantum level is really strange. To use a real-world example again, if we saw a car being driven at speed toward a solid wall what we'd expect would be a loud bang followed by the tinkle of falling glass and the quiet hiss of escaping steam. What we definitely wouldn't expect is for the car to pass through the wall as if it simply wasn't there and continue on it's way totally unaffected. Quantum particles do this sometimes; it's called tunneling. If moving particles hit a barrier, most of them get stopped but some pass straight through it, like the girl in the X-Men films who can walk through solid walls. It sounds quite insane, but it's an observable effect and it's coming to a smartphone near you.
This wierdness is harnessed in a material called QTC (Quantum Tunelling Composite) recently invented by a Yorkshire-based company and already licensed by two Japanese corporations that make components, particularly touch screens, for mobile phones and other portable devices. Embedded within the material are conductive nanoparticles which, if they were in contact, would allow the material to conduct electricity. It doesn't, however, because the particles are slightly separated - except for the tiny current that flows anyway because some of the electrons quantum-tunnel through the insulation that surrounds them. Compressing the material forces the conductive particles closer together, this increases the probability that tunneling will occur and so the current rises.
What does this give us? Pressure sensitive material!
Think of a touch screen that responds not only to the speed of the finger swiped across it but also to how hard the finger presses and how that pressure varies throughout the stroke. It would make the best of today's touch-screen devices seem as clumsy as a mechanical keyboard. Imagine also placing that material on the surface of a mechanical hand and giving it what we humans take for granted - touch sensitive skin. A robot with a hand like that would be able to sense how much pressure it was applying with it's fingers and adjust accordingly - enter the gentle robot surgeon, the kitchen helper that can hold an egg without crushing it, or the prosthetic that allows the wearer not just to move but also to feel. That's a massive improvement over a simple motorised claw, and it's all thanks to quantum physics.
Regular readers will be wondering if there's a spiritual angle to all this. Well, sometimes we humans gain a little knowledge and then become arrogant, strutting intellectually around God's universe like we own the place and telling him how He should behave. That's when God lets us discover something like quantum physics to show us that there's far more to Him and to the hidden mysteries He's created than we're ever likely to understand. As the book of Ecclesiastes so neatly puts it, "God is in Heaven and you are on the earth. Therefore let your words be few."
The Bible states, and quantum physics confirms, that "With God, nothing is impossible." So be careful next time you decide to throw a snowball, because if there's one thing that quantum physics shows us above all else, it's that God has a really mischievous sense of humour.