Quantum phr33x - Fallout #35

John Simpson brings us one step closer to feeling like Trekkies...

Let's go on a journey back through time, back to the days of secondary school (quite a long time for some of us). Picture your physics teacher: a bespectacled bald man, ranting on about mass and acceleration, and how fat people will never be able to travel faster than the speed of light. Picture the grade on your final exam, and recall with brutal realisation the knowledge that you'll never understand the physical world.

Well, here's a shock. That stuff you tried to learn? It's all crap.
Not so much at the bus-sized level, but when you start talking about tiny particles -- like light and M&Ms -- you enter the realm of unpredictability. A world where up is down, Simon Crean is PM, and nothing makes the slightest bit of sense. The world of quantum physics.

Quantum physics popped up in the year 1900, when German physicist Max Planck (not to be confused with his brother, Warkthe) proposed that energy comes in little packets, called 'quanta'. Light is a good example -- its packets are chock full of photons. Kind of like a little Lotto barrel that's moving really, really fast.

These packets of photons merrily bob around, bouncing off stuff in a virtual mosh pit of radiosity. But here's the conundrum: it seems that each particle in the packet likes to do its own thing -- but what that thing is, we don't know. Throw a packet of light at a mirror and some photons get reflected, and some slip through. Trying to predict which ones go through is like predicting your girlfriend's mood: impossible.

In the world of classical physics, if you can't predict what a particle is going to do you're likely to get a smack to the back of the head. Einstein, a true classical theorist, said it was like someone rolling a billiard ball at you with your eyes closed: until you look at the ball, it's neither red nor blue, and it's both (uh... right). It's only when you observe the ball does it 'become' a colour.

Fantastic. Essentially, we have a sub-atomic world that behaves like a cross dresser on heat. They can't decide what skirt to wear with what shoes -- so instead wear them all. . . and wear nothing. . . at the same time. And here I was thinking my life was confusing.

So now you're holding your head in your hands and rocking back and forth, asking what this has to do with you. At this point in time, thankfully, not much. Snooker is still a dull game, and guys in skirts still give me the willies. But all this is about to change, as new technology advances into the quantum age.

First on the list is the quantum computer. In theory, a quantum computer would be a technological revolution, just like the in-dash cup-holder. Imagine each electron in the computer is a 1 or a 0. With quantum physics the electron actually exists in both states, until you look at it. So each 'bit' can do two operations. Two bits can do four, and so on and so on. A regular rabbit hutch of bits -- essentially massive parallelism.

There's only one problem: once you observe the answer, you influence the behaviour of the entire system. Each electron reverts to a singular state, and your massive parallelism becomes a beaker full of sticky liquid.

Another example -- matter transportation. Okay, at this point some of you are tossing your magazine out the bus window, disgusted at the ravings of this Star Trek nut. But amazingly, it's been done (not the tossing, the transporting). Last year two teams of scientists, in Rome and Innsbruck, managed to teleport a photon from one side of their labs to the other. Utilising the freaky way that particles can share quantum information, the researchers literally beamed-up a light beam!

Great stuff, although people are a lot bigger than photons, and transferring that much quantum information looks damn near impossible. Who knows, maybe in ten years we'll be able to transport small things like buttons and grapes. Great for the textiles and sultana industries, but not as glamorous as appearing in the middle of the MCG in drag.

So next time you use a mirror or watch light stream through a frosty window, give someone a nudge and say 'that's quantum physics'. Then you'll know exactly what we Star Trek fans feel like...