We Need to Replace Moore's Law to Make Way For Quantum Computers, But What's Next?

A brand-new revolutionary technology is about to emerge, and it has the potential to significantly increase computer power.

And Hartmut Neven, the head of Google's Quantum AI Labs, has suggested a new rule that is akin to Moore's Law, which has tracked the advancement of computers for more than 50 years, to forecast the rate of development of this new "quantum computing" technology.

But can we rely on "Neven's Law" to accurately reflect the state of quantum computing today and, more crucially, what lies ahead? Or is it simply too early in the competition to make this kind of determination?

 

Contrary to traditional computers, which can only store data as electrical signals with one of two possible states (1 or 0), quantum computers may store data using a variety of physical systems, including electrons and photons.

These may be designed to encode data in several states, which allows them to do computations much more quickly than conventional computers.

 

As of now, no one has created a quantum computer that can surpass current supercomputers. Quantum computing is still in its infancy. But despite some skepticism, enthusiasm is pervasive about how quickly things are moving now.

Therefore, knowing what to anticipate from quantum computers in the future would be useful.

 

According to Moore's Law, the processing capability of conventional digital computers has a tendency to double every two years or thereabouts, leading to what is known as exponential growth.

The rule, which bears Gordon Moore's name as a co-founder of Intel, more precisely characterizes the pace of increase in the number of transistors that can be put onto a silicon microchip.

 

However, quantum computers are made in a very unique way to work around quantum physics. Moore's Law is thus invalid. Herein lies the application of Neven's Law. According to this, the power of quantum computing is growing "doubly exponentially relative to conventional computing."

Exponential growth is defined as the expansion of anything by powers of two, such as 2^1 (2), 2^2 (4), 2^3 (8), 2^4 (16), and so on. Doubly exponential growth, also known as 2^2 (4), 2^4 (16), 2^8 (256), 2^16 (65,536), and so on, is the development of anything by powers of two.

To put this in perspective, if Moore's Law had applied to classical computers, we would have experienced twofold exponential growth (instead of singly exponential development), and by 1975, we would have had laptops and cell phones.

Neven anticipates that the so-called quantum advantage will soon arrive as a result of this extremely rapid speed. The moment when a relatively modest quantum processor surpasses the most potent traditional supercomputers is a much-awaited milestone.

 

Based on an internal observation, its expansion has doubled-exponential causes. Neven said in an interview that Google researchers are improving the accuracy of their quantum computer prototypes. This enables them to develop increasingly sophisticated and potent systems with each iteration.

According to Neven, this improvement is also exponential, following Moore's Law. However, compared to a conventional processor of the same size, a quantum processor is intrinsically and exponentially superior.

 

This is due to the fact that it takes advantage of a quantum phenomenon called entanglement, which enables the simultaneous execution of several computing processes and leads to exponential speedups.

So, to put it simply, if the development of quantum processors is exponential and they are exponentially quicker than classical processors, then the development of quantum systems is double exponential relative to their classical counterparts.

A note of caution

We must be cautious even if this seems wonderful. To begin with, Neven's judgment appears to be based on a few prototypes and progress that was assessed over a little period of time (a year or less).

 

With so few data points, several additional extrapolated growth patterns might readily be fitted.

The fact that technical issues that are currently small in importance might become considerably more significant as quantum processors become more complicated and powerful is another practical concern.

 

For instance, even a little amount of electrical noise in a quantum system might result in computing mistakes that increase in frequency as processor complexity increases.

Error correction methods might be used to address this problem, but doing so would essentially require adding a lot of redundant backup hardware to the CPU.

 

Thus, the computer would have to grow far more complicated without receiving much, if any, additional power. This type of issue may have an impact on Neven's forecast, but right now it's just too early to tell.

Although Moore's Rule was only an empirical observation and not a fundamental law of nature, it accurately predicted the advancement of traditional computing for nearly 50 years.

 

It served as a catalyst for the semiconductor industry to adopt a consistent roadmap, set regular milestones, evaluate investment amounts, and project future revenues, thus in a way it was more than simply a forecast.

Neven's finding will undoubtedly have effects that go well beyond the simple prediction of quantum computing performance if it turns out to be as prophetic and self-fulfilling as Moore's Law.

 

For starters, it's unclear at this point whether quantum computers will be extensively adopted for commercial purposes or remain niche consumer goods. But if Neven's Law is accurate, we won't have to wait long to find out.

M. Fernando Gonzalez-Zalba, a research fellow at the University of Cambridge, and Alessandro Rossi, Chancellor's Fellow, Department of Physics, University of Strathclyde.