I like the word quantum. It's a very future sounding word. Fantasy writer Terry Pratchett likes it too, and uses it in his novels to describe anything that can not really be described or understood. Considering his stories take place on a world that drifts through space balanced on 4 giant elephants standing on a turtle, it's a word he uses fairly often.
Quantum is like a bridge between what's possible and what's probable. It makes science fiction science fact, and it's here. Well, almost here. The issue of quantum computing has been puzzling researchers for roughly 3 decades, and now it looks like we're only a few short years away from buying them from our local tech stores.
What's the big deal with quantum computers anyway? Well, they're super-fast and super-efficient, making current PCs look like the monstrous machines that took up an entire room when they were first developed. According to Fred Chong, from the University to California, a quantum computer would be able to solve in mere months problems that would take a conventional computer millions of years.
The key to their "superness" is the fact that quantum bits or quubits are not bound by the conventions of time and space as we know them. Normal electrons spin either clockwise or anti-clockwise. Quantum electrons spin in both directions at once. This ability to transcend a single state of existence means that when they're used in computing, quantum electrons transform conventional "bits" into quubits. Conventional bits can be either a 1 or a 0, but qubits can be both at the same time.
In quantum mechanical terms, the qubits exist in superposition, which leads to an inherent parallelism, which according to physicist David Deutsch allows quantum computers to work on a million computations at once. Current PCs can work on only one.
One of the most important benefits of quantum computers, besides all the other "superness", is that they'll make silicon based microchips obsolete. This is a good thing because within about 4 years silicon chips will have discovered themselves out of existence, being too small to be of any practical use.
One of the ways in which they'll negate silicon chips, and completely revolutionize the way computers are wired, is through the quantum property of teleportation. Using teleportation, information about one particle will be transmitted to another without using any wires at all. In Star Trek terms, information is labeled from one particle to another. The nice thing about quantum is that there will always be enough power to do this. No flailing about in outer space, panicking about another Klingon attack for these babies. You're always good to go.
Simple quantum computers are already in existence, but they're now near achieving what they're capable of. In 2007, a Canadian company, D-Wave, created a 16-qubit (the goal is at least 30 qubits) quantum computer that could solve sudoku puzzles. Other quantum computers can solve the riddle of Schrodinger's cat (a cat in a box with poison, is it alive or dead? Until you open the box and have a look, it occupations both states, not like quantum electrons and quubits), considered one of the most important equations in quantum mechanics.
It may not seem like much to the man / woman on the street, but it's enough to get quantum physicists out of their baths and running naked down the street with cries of "Eureka".