Computer world is set for a revolution
Howard Burton
November 29, 2004

Living in the "high-tech age," we have become accustomed, almost inured, to the rapid march of technological progress: cellphones and PDAs seem to grow smaller and more powerful by the hour, television sets are getting both flatter and sharper, and digital animation is transforming Hollywood.

And computers? Well, everyone knows the old saw by now: by the time you plug in your new computer in your living room, it probably already needs an upgrade. The increase in computational power of today's desktops are only matched by the increasing computational demands of today's computer games.

Is there any end in sight? Well, yes, there certainly is. In the 1970s, Gordon Moore, the co-founder of Intel, remarked that the memory capacity of a computer chip was roughly doubling every 18 months while the size of the chip itself remained the same.

Of course, the only way that this rate of increase could be maintained was for technology to develop ways of packing more transistors into the same space -- i.e. somehow shrink the size of transistors and develop technologies to handle the associated issues, such as improving efficiencies and heat loss per calculation.

The fascinating thing about Mr Moore's observation is that, however unscientific it might have been, it has held to the present day. Unsurprisingly, perhaps, it is now referred to as Moore's Law.

So far so good. But if trends continue, we will be in a rather different situation by 2020, for by then it is clear that, according to Moore's Law, transistors will have to be the size of atoms -- and atoms obey strikingly different laws of nature than their larger counterparts.

In short, according to Moore's Law, by roughly 2020 we will be in the regime of quantum mechanics, rather than classical mechanics.

What does this mean and why should we care?

For a physicist, the notion of a "quantum computer" -- a new form of computational device harnessing the laws of quantum mechanics rather than classical mechanics -- is more than just something forced on us by the inevitable march of technology.

Even if the day when a quantum computer is necessary from a technical view were 50 or a 100 years away, it still would be an intellectually stimulating subject area. Thinking about these issues makes us further understand the very notion of what information is and how it can be manipulated.

As well, many people are captivated by the idea that the new field of "quantum information theory" -- a marriage of the physics of quantum mechanics with the computer science framework of information theory -- might shed some light on the mesmerizing subtleties of quantum theory that have plagued physicists and philosophers for almost 80 years.

Indeed, quantum computing is also a example of the typically long time scales between the conception of a fundamental idea and its technological development.

In a now landmark address to the American Physical Society entitled There's Plenty of Room at the Bottom, the famous American physicist and Nobel laureate Richard Feynman said: "When we get to the very, very small world -- say circuits of seven atoms -- we have a lot of new things that would happen that represent completely new opportunities for design.

"Atoms on a small scale behave like nothing on a large scale, for they satisfy the laws of quantum mechanics. So, as we go down and fiddle around with the atoms down there, we are working with different laws, and we can expect to do different things."

''We can manufacture in different ways. We can use, not just circuits, but some system involving the quantized energy levels, or the interactions of quantized spins, etc."

It is always hard to pinpoint the start of a scientific movement -- typically, different people take credit for different approaches at different times. But there is almost universal consensus that Feynman's lecture was the impetus to get people seriously thinking about quantum technologies.

The date of Feynman's famous lecture was 1959.

Forty-five years later, extremely primitive quantum computers have been developed that do basic arithmetic calculations. The hope is that in another 20 years -- roughly 100 years after the theory of quantum mechanics was developed -- we might have a quantum computer that can perform calculations that no classical computer could ever do.

One hundred years of effort might seem like a shockingly slow rate of progress. But there is a big difference between incremental technological change and fundamental change. Incremental change can be impressive, but has its limits. Fundamental change is the only way to take us to the next level.