How Far Off Is Quantum Computing Really?

Quantum computing might be closer than you think. The 2020s could very well become the decade when quantum computing goes from lab environments to usage in specialized infrastructures.

Last Monday, QuTech – a collaboration between Dutch research facility TNO and the Technical University of Delft – published its Annual Report in which it looks ahead to the age of the quantum computing. Outside the quantum community, it is commonly believed that the era of quantum computing is still far off, even though there have been several breakthroughs in the Oughts and Tens that bring a universal quantum computer much closer. In the real world, outside lab environments, companies like D-Wave have been making waves with their qubit-infused traditional computers that bring a few quantum-like capabilities to computing. Several organizations like NASA and Google are using these machines in their infrastructure.

Quantum advantage versus supremacy

But this is all still far removed from universal quantum computing: a form of quantum computing that beats traditional binary computing no matter which task it is performing. D-Wave’s computers certainly bring a speed upgrade compared to traditional counterparts that use only bits. These qubit-machines bring faster solutions to optimization problems, not a universal speed boost. These computers are therefore well-suited for optimization problems (finding the best available solution for a given mathematical problem) but not every problem that requires compute is an optimization problem. 

There are two developments to keep an eye out for. The first is the moment where quantum computers perform calculations that would not be possible for traditional binary systems, a development known as “quantum supremacy”. The second is a moment where quantum computers can perform all practical tasks better than a traditional computer, a development known as “quantum advantage”. Last year, Google claimed to have achieved quantum supremacy. In particular, quantum processor Sycamore was able to sample the output of a pseudo-random quantum circuit. This task would have taken a supercomputer much longer, although the actual amount of time is up for debate. Google claims it would take a binary computer 10,000 years, while several experts figure it would take a few days. So not the enormous jump Google claims, and not really “quantum supremacy”, but a leap forward nonetheless.  

Ifs and buts

Whereas some scientists praised this achievement, others are more skeptical, as Google’s example of sampling a random number, is a hugely specific task that might not be applicable for other use cases. Exactly the problem D-Wave ran into when marketing its hybrid quantum computer. Practical users look for quantum advantage, not quantum supremacy. One of those more skeptical observers is IBM. After Google’s announcement, the IT giant published a blog post containing some ifs and buts, mainly in regard to resource usage and the progress computing has made in about 75 years. Our history with binary computing brought us programming tools, libraries, languages, algorithms, and much more. Quantum computing, however, is still a brand new frontier. It will be a while before quantum computing can actually compete with traditional computing. 

Still, even IBM is enthusiastic about the future of quantum computing and also sees some great promise in the results of Google’s limited experiment with a very specific task. The company mainly wishes people to understand that this is, in no shape or form, proof that quantum supremacy has been achieved. “Building quantum systems is a feat of science and engineering and benchmarking them is a formidable challenge. Google’s experiment is an excellent demonstration of the progress in superconducting-based quantum computing, showing state-of-the-art gate fidelities on a 53-qubit device, but it should not be viewed as proof that quantum computers are ‘supreme’ over classical computers,” wrote Edwin Pednault, John Gunnels & Dmitri Maslov, and Jay Gambetta for IBM. Scott Aaronson, founding director of the Quantum Information Center at the University of Texas, agrees and wrote in an opinion piece for the New York Times that Google’s achievement is a critical milestone in the development of quantum computers.

Platforms and tools

It seems that we’re very close to entering an era of quantum computing. Companies like Microsoft and IBM are preparing their quantum platforms (Azure Quantum and IBM Quantum Experience respectively) for prime time use, so developers can experiment with this new technology. Financial institutions, like Dutch bank ABN AMRO, are looking into securing data in a quantum age. Companies like Thales are working on quantum-resistant cryptographic solutions, while standards organization NIST is on the verge of establishing a post-quantum public-key cryptography standard. So while universal quantum computing hasn’t arrived yet, a time when infrastructures get qubits in their bits is definitely at hand. Aaronson in his NYT piece: “We’re now in an era where, with heroic effort, the biggest supercomputers on earth can still maybe, almost simulate quantum computers doing their thing. But the very fact that the race is close today suggests that it won’t remain close for long.”

The big question, then, is not so much a question of how long will it take for a competitive universal quantum computer to be built – as there are already examples of universal quantum computers and of machines that use a hybrid of binary computing, logic gates, and qubits – but rather of how long it will be for the required tools to make this technology more usable exist. Already we can see progress in open libraries. For instance, OpenQL, a framework for quantum programming, helps developers who are familiar with C++/Python to program quantum software. Similarly, Microsoft provides an SDK for developers to learn about quantum. QuTech has Quantum Inspire, a platform for quantum programmers to develop and test their quantum algorithms. And there are MOOCs available for anyone who wants to get hands-on with quantum computing and prepare for the future of IT.

But make no mistake, it is still a nascent technology. Compare the birth of quantum computing to the advent of binary computing. The first silicon chips were developed in laboratory environments in the 1940s but it wasn’t until the deep pockets of the American government supplied the resources to further develop this technology in the 1960s (thanks to the conflict with the USSR) that computing based on silicon became a mainstay in the world of science. The 1970s begat us micro-computing, the 1980s home computing and networking, the 1990s internet, and that is when things really took off. So that’s close to fifty years from the birth of the binary computer to the dawn of the age of the internet that made computing ubiquitous.

How close are we?

For quantum computing, it probably won’t take half a century to go from the birth of the universal quantum computer to a quantum computing age. The reason is that there are already frameworks in place that will vastly speed up the development of quantum applications. Platforms like GitHub and StackOverflow didn’t exist when binary computing took off, and these would have saved developers unnumerable hours of time (re)inventing code. MOOCs made collaborative learning easy and developers can now use resources like edX and Coursera to hone their quantum developing skills. 

Shared repositories and libraries will enhance the speed of development compared to the era of traditional computing, but also the work provided by automatization in the form of applied augmented intelligence will greatly speed up this process. It is very hard to predict an exact time-frame. However, with software, development tools, collaborative frameworks, and infrastructure in place, it is easy to see this process from going to the creation of universal quantum computers to these machines becoming close to ubiquitous (in the back-end at least) in a much shorter time span.

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  1. July 5, 2020

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