What is Quantum Supremacy

Clint Brown

For nearly a decade now, physicists and tech gurus have had interesting debates over quantum supremacy. Does the phrase sound Greek to you? If so, you are not alone. To better grasp what the discourse is about, first, you need to understand what classical (traditional or conventional) computers and quantum computers are. 

Quantum Computer sitting in dark room demonstrating what is quantum supremacy

You see, if you have used an Apple or Dell computer (there are other brands on the market!) before, then you have used a classical computer. Sure, these are the conventional devices everyone uses. Basically, classical computers are electronic devices designed to process data with transistors that represent 1 or 0 of binary information at a single time.

The transistor is a switch that either allows or blocks information from entering a computer. Transistors are also combined to create logic gates that enable users to compute information. Here, the smallest unit of information is a bit. From schools to banks, malls to hospitals, everyday people use digital devices for meeting their daily needs. However, the key limitations facing these electronic devices are poor computational power and speed.

To tackle this problem, in the 1980s, American physicist Richard Feynman and Russian mathematician Yuri Manin proposed the concept of quantum computing. Unlike traditional computers, quantum processing devices calculate qubits (quantum bits) that represent 0 and 1 simultaneously. Keep in mind that qubit is the basic unit of quantum information. This type of digital device can exist in multiple states. They leverage the laws of quantum mechanics to solve complex problems a lot faster than today’s smart devices – thanks to their powerful computational capabilities.

What is Quantum Supremacy?

Coined in 2012 by writer and physicist John Preskill, quantum supremacy is a phrase used to mathematically demonstrate that quantum devices can tackle problems at a much faster rate than today’s digital devices. It can also be problems that today’s digital devices cannot solve at all.

This supremacy is the experimental demonstrations that show how the innovative devices are better than their conventional counterparts in terms of speed and computational power. To attain this supremacy, scientists must prove beyond reasonable doubt that specific complex puzzles can only be solved and faster too if the cutting-edge devices were used as opposed to using today’s computers. 

Well, one of the most common puzzles that always comes to mind whenever experts discuss this supremacy is the Shor’s algorithm, an algorithm that factors integers in polynomial time using a quantum device. Named after American professor of applied mathematics Peter Shor, Shor’s algorithm factors a number, N, in 0((logN)3) time and 0(logN) space.

To be clear, if anyone tries to solve this using traditional computers, they won’t be able to effectively accomplish the task. The reason is that today’s digital devices cannot run it efficiently. However, quantum devices can modify and solve it at the drop of a hat. But what’s the fuss? The essence of this algorithm is that public key cryptography can be easily broken with the aid of a quantum device, thereby exposing their encrypted details.

With respect to its real world application, think of cryptocurrency, which is cryptographically protected from unauthorized users. This means that digital coins become vulnerable to cyberattacks because quantum devices carry out operations much faster.  

Why does Quantum Supremacy matter?  

Why should anyone be worried sick about quantum supremacy, anyway? Well, this supremacy matters because the world is likely to experience a generation of computers that are much faster than the traditional devices everyone uses today.

In precise terms, this innovation will revolutionize artificial intelligence and machine learning in ways we never thought possible. Its feasibility would see the world solve complex problems in microseconds. It must be established here that there are complexities and interacting variables that today’s smart devices are unable to solve. However, quantum technology introduces a paradigm shift that will see people tackle these challenges in no time. 

Now, let’s look at it from another viewpoint. As you know, there are life mysteries that today’s digital devices haven’t been able to crack. Nevertheless, with the help of complex simulations, it becomes a lot easier to simulate many intricate systems. For instance, the leading Swiss pharma company, Roche, hopes to apply this emerging technology in expediting the development of drugs and vaccines, thus protecting humans from deadly ailments like Covid-19 and cancer. Roche is also optimistic that the technology can potentially facilitate the cure for Alzheimer’s disease.

Similarly, other researchers are of the opinion that the technology can significantly minimize the cost of research as well as reduce the use of humans and animals in clinical trials.  

Is Quantum Supremacy Achievable? 

From all indications, quantum supremacy remains an interesting debate. This is largely because quantum technology is still (and constantly) evolving. However, many tech pundits firmly believe that the powerful devices haven’t reached the point where it can completely kick conventional devices into obsolescence.

To their way of thinking, quantum devices cannot show supremacy over conventional computers now; the reason being that carrying out operations with the former requires a lot of qubits. Sadly, as the qubit requirements of these disruptive devices increase, users’ chances of running into errors worsen. Since that is the case, the implication is that the innovative technology will lose its credibility and perceived supremacy over today’s generation of computers.    

Sphere with tunnel through middle, used to demonstrate quantum physics

In contrast, proponents of this supremacy argue that it is already playing out. One of the evangelists of this concept is the American tech giant, Google. In its October 2019 publication, Google opined that its quantum processor known as Sycamore was able to tackle a complex problem in 200 seconds. In comparison, the tech giant noted that it would take IBM’s classical computer – known as Summit – about 10,000 years to solve the same puzzle.

It is worthy of note that Summit is as big as two basketball courts joined together and was largely considered the world’s fastest computer at the time. In a swift response, multinational tech corporation IBM faulted Google’s claim, saying that Summit could tackle the same problem in two and half years, not 10,000 years as Google initially suggested.

But then, regardless of what the IBM team thinks, it is a feat that Google’s Sycamore could solve in seconds what their Summit could solve in years. Without a doubt, this goes to show that quantum supremacy is more feasible than many critics think. Despite that, it is noteworthy that these disruptive devices are still far from going ubiquitous because they haven’t been fully commercialized in large scales yet. 

About the author

Our team consists of PhD and industry experts specializing in quantum computing. With extensive experience in research and practical applications, they are dedicated to helping businesses understand and harness the power of quantum technology for innovation and growth.

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