We need to replace Moore's law to make room for Quantum computers, but what's next?

A new breakthrough technology is on the horizon and it promises to bring computing power to unprecedented and unimaginable heights.

And to predict the speed of progress of this new "quantum computing" technology, Google's Quantum AI Labs director, Hartmut Neven, has proposed a new rule similar to Moore's law that measures the progress of computers for more 50 years old.

But can we trust the "Neven's Law" as a faithful representation of what is happening in quantum computing and, most importantly, what awaits us in the future? Or is it just too early in the race to arrive at this type of judgment?

Unlike conventional computers that store data as electrical signals that can have one of two states (1 or 0), quantum computers can use many physical systems to store data, such as electrons and photons. .

These can be designed to encode information in multiple states, which allows them to perform exponentially calculations faster than traditional computers.

Quantum computing is still in its infancy and no one has yet developed a quantum computer that can outperform conventional supercomputers. However, despite some skepticism, there is widespread enthusiasm for the speed with which progress is being made.

It would therefore be useful to have an idea of ​​what we can expect from quantum computers in the years to come.

Moore's Law describes how the processing power of traditional digital computers has tended to double every two years or so, creating what we call exponential growth.

Named in honor of Gordon Moore, co-founder of Intel, the law specifically describes the rate of increase in the number of transistors that can be integrated into a silicon chip.

But quantum computers are designed very differently according to the laws of quantum physics. And so Moore's law does not apply. This is where the Neven law comes in. It indicates that the power of quantum computing is experiencing "a doubly exponential growth compared to conventional computing".

Exponential growth means that something develops by powers of two: 2 ^ 1 (2), 2 ^ 2 (4), 2 ^ 3 (8), 2 ^ 4 (16), and so on. A doubly exponential growth means that something develops by powers of two: 2 ^ 2 (4), 2 ^ 4 (16), 2 ^ 8 (256), 2 ^ 16 (65,536), and so on.

To put this in perspective, if traditional computers had grown doubly exponentially under Moore's Law (instead of an isolated exponential), we would have had laptops and smartphones today. In 1975.

This extremely fast pace should soon lead, says Neven, to the so-called quantum advantage. This is a long-awaited step in which a relatively small quantum processor exceeds the most powerful conventional supercomputers.

The reason for this doubly exponential growth is based on internal observation. According to an interview with Neven, Google scientists are improving their ability to reduce the rate of error of their quantum computer prototypes. This allows them to build more complex and powerful systems at each iteration.

Neven maintains that this progress itself is exponential, much like Moore's Law. But a quantum processor is intrinsically and exponentially better than a conventional processor of equal size.

Indeed, it exploits a quantum effect called entanglement that allows performing different computational tasks at the same time, producing exponential accelerations.

Thus, simplistically, if quantum processors grow at an exponential rate and are exponentially faster than conventional processors, quantum systems grow at a rate that is doubly exponential with respect to their conventional counterparts.

A note of caution

While this sounds exciting, we must be cautious. To begin with, Neven's conclusion seems to be based on a handful of prototypes and measured progress over a relatively short period of time (one year or less).

So few data points could easily be created to fit many other models of extrapolated growth.

There is also a practical problem that, as quantum processors become more and more complex and powerful, minor technical problems now become much more important.

For example, the presence of even modest electrical noise in a quantum system could lead to computational errors that become more and more frequent as the complexity of the processor increases.

This problem could be solved by implementing error-fixing protocols, but this would involve the addition of many backups to the processor that are otherwise redundant.

Thus, the computer should become much more complex without gaining much extra power, if any. This type of problem could affect Neven's prediction, but for now, it's too early to call.

Although it was an empirical observation and not a fundamental law of nature, Moore's Law foresaw the advancement of clbadical computing with remarkable accuracy for about 50 years.

In a way, it was more than just a prediction, as it encouraged the microchip industry to adopt a consistent roadmap, set regular milestones, badess the volume of business, and improve the business case. Investment and evaluate potential revenue.

If Neven's observation turns out to be as prophetic and fulfilling as Moore's Law, it will certainly have ramifications far beyond mere prediction of quantum computing performance.

On the one hand, nobody knows at this stage if quantum computers will be widely marketed or will remain the toys of specialized users. But if Neven's law is true, it will not be long before we discover it.

Alessandro Rossi, Fellow of the Chancellor at the Department of Physics of the University of Strathclyde and Mr. Fernando Gonzalez-Zalba, Research Fellow at the University of Cambridge.

This article is republished from The Conversation under a Creative Commons license. Read the original article.