Quantum computers use particles as their "bits" instead of the silicon bits we use today. These particles, unlike today's bits which have two states 0 and 1, have no state, so to speak. They can be 1, 0, or something else simultaneously. They don't become a 1 or a 0 or whatever until we "look at it," so to speak. They're constantly changing until we freeze their states, at which point we get a result.
One big advantage of quantum computers are their memory space. You can have exponential memory space from a linear set of bits. Classic problems such as finding the least expensive route between a set of, say, cities that goes to each city once, then back to the origin, becomes much easier.
What's done now is that the computer goes through each possible route. When it's done, it takes all the results and chooses the one that resulted in the shortest route. As you can see, from an N number of cities, you can have an exponential number of possible routes to look through. Therefore, computing stuff like this takes a looooooonng time and a lot of memory.
Quantum computing does not work in this "linear" sort of way. Instead, it's "probalistic." You can optimize a quantum computer to work on a certain problem like the one stated above. You run it, then after a certain time interval you freeze the states of the particles and take the result. If the result is the one you wanted, then you take it. Otherwise, you just run the computer again.
So it's basically like rolling a dice, and randomly searching for the right number. The thing is that a quantum computer has huge memory space, and the whole process takes very little time. Additionally, the probability of finding the right answer is something like 99.9%.
It's pretty hard to understand, but apparently that's how quantum computers work.
As a note, quantum computers are apparently so good that they can solve the most complex of encryption codes today in a matter of minutes. People have in fact done work on making encryption that can actually stand up to quantum computing, but even then it usually fails. So you KNOW you've been cracked, but you can't actually stop them from doing it.
Another neat thing from all this is that if you "tangle" two particles together, then separate them a certain distance apart, then change the state of one, the other will change as well, instantaneously. Scale these particles up into full computer systems, put one on Earth and the other on a Mars expeditionary team and you have, theoretically, instantaneous communications between the two.
Therefore, real FTL communication is, theoretically, much closer to our grasp than we think it is.
Of course, this whole quantum computing thing is at least many decades off into the future, but theoretically it's all known.
We currently use silicon chips now, but the next stop will probably be diamond chips, to account for stuff like rising heat. Organic stuff could be next, possibly. Then farther down the line we have quantum computers.
Actually, there is something even farther called a non-deterministic chip. What it does is, say in the route problem above, when you start it up it is immediately guaranteed to choose the cheapest route. It somehow just knows that it's the shortest route.
If we somehow build a non-deterministic system, it'd be like basically building something that can read the future.
But that's WAAAYY out there, so I'll stop now and let all this fly completely over your heads.
