Deyan Mihaylov: Аdvances in quantum technologies are arriving at an exponential rate

A division between the UK and the rest of Europe will spеll disaster for scientific progress

Photo: Personal archive Dr. Deyan Mihaylov

I believe that eventually, quantum supremacy will be achieved by a private research lab outside of Europe. That is not to say that research in Europe will always be lagging behind, but European universities and research centres need to concentrate on ambitious and risky goals, and then invest wisely in achieving them, says Dr. Deyan Mihaylov, postdoctoral fellow at the Max Planck Institute for Gravitational Physics, in an interview to Europost.

Lately, quantum computing has transformed into one of the hottest topics. Yet, for many the term “quantum computer” is still abstruse. So, before we begin, could you give the broad public an overview of what a quantum computer actually is and how it differs in comparison to the traditional computer?

That is a broad question in its own right, but perhaps the best way to introduce the topic would be to say that quantum computers are a new form of computing hardware which uses certain quantum mechanical effects in order to perform some classes of calculations faster than binary machines. The last part of that sentence is particularly important: only particular types of problems would actually benefit from quantum computers, and for some of them, the speed-up would be exponential.

Could you give an example of what operations they would be able to perform that a traditional computer could never do?

That is a difficult question: if you have a powerful classical computer, and give it enough time – years, perhaps – it would be able to solve just about any computational problem in the world. There are issues with the so-called non-polynomial (NP) problems, whose solutions often require amount of time which grows exponentially with the size of the problem. Therefore, a binary computer would require many millennia to produce a solution to large instances of these problems. This is where quantum computers come in – their promise is to solve some of these NP problems in polynomial (P) time, i.e., much faster.

The easiest problem which could be proposed as an example is finding the primary factors of a number. For a classical computer, is it easy (and therefore, fast) to find the product of 2 numbers. However, if the same machine tries to factorise the result, i.e. find the two numbers which were multiplied together in the first place, it would be able to do it much slower. In other words, multiplication is a fast operation, while factorization is a slow one. This becomes quickly apparent for large numbers, for example if we try to multiply two 30-digit prime numbers, and then find the prime factors of the result. Shor’s algorithm, developed in 1994, is a quantum algorithm which is able to find the factors of a number in a polynomial time, i.e. much faster than on a classical computer.

Does this mean that quantum computers still exist at an experimental level only?

It really depends what you mean by “experimental”. Currently we already have quantum computers which can do things that their binary counterparts cannot accomplish, especially in traditionally academic fields like quantum chemistry, for example. In this regard, quantum computers are no longer experimental, but are already used in research. It is correct to say that it would be another few years before we have quantum computers which can solve problems that are intractable for even the most powerful supercomputers today. This moment is approaching quickly, though, and the advances in quantum technologies are arriving at an exponential rate.

What technologies and knowledge are still needed to make such machines a reality?

The challenges which remain to be solved before we can start building full-scale quantum computers are mostly of engineering nature. Most importantly, the community is still arguing which is the best physical carrier of qubits and it is quite possible that several suitable solutions will emerge in the end. The issue of fault tolerance is currently tackled using sophisticated solutions at the software level, however high-fidelity qubits are also an important ingredient for large-scale quantum computing. Finally, a lot of research is underway to figure out how to utilise these qubits in quantum logic circuits. The community steadily invests resources in these areas, hence I am confident that all of these challenges will be resolved in the coming years.

Many claim that when obstacles have been overcome the quantum machines will shape new computing and business paradigms by solving computational problems that are currently out of reach. Do you agree?

We should always be cautious when some new technology is poised to “disrupt” the current paradigm. This is a bad way to paint any technological advance. Innovations should complement our current technological stack, not disrupt it, unless we are talking about AI Armageddon. Quantum computers are bound to help us solve many problems which are currently beyond our reach, that is for sure, but they would do it by working jointly with large supercomputers, not on their own.

In that regard, the advent of quantum computers would allow us to solve many optimisation problems in logistics, in aerospace engineering, in materials research. Other quantum algorithms would make it possible to design more effective drugs and perform clinical trials quicker. The field of cybersecurity would also enjoy some invigoration, as some traditional encryption methods would be phased out in favour of quantum encryption.

You mentioned quantum encryption here. It is expected to contribute to extreme communications security, so if it really is “unhackable,” as claimed, would it not make the cybersecurity field rather obsolete than resurgent?

It is true that quantum encryption is theoretically physically unbreakable, however practical implementations are still burdened with some security flaws due to imperfect fault-tolerance of the hardware. Nevertheless, quantum encrypted networks have already demonstrated incredible performance and reliability over short and medium distances, and new advances in hardware manufacturing will make them accessible to more customers with broader spectrum of requirements.

I doubt quantum encryption would completely replace all current cryptographic solutions, however some of the algorithms which are used at present would become obsolete and would be replaced by modern, quantum-proof alternatives.

How would you characterise the current state of quantum research in Europe when compared to other regions in terms of investment and accomplishments?

Quantum technologies in Europe have traditionally been confined to university research labs, and this is evident by the number of such centres on the continent at present. Other places, like Silicon Valley, or countries like Canada and Japan were quick to realise the potential of quantum computers, and encouraged the private sector to take part in the initiative. Europe is now also taking this approach, which is encouraging, but there is a long way to go.

I believe that eventually, quantum supremacy will be achieved by a private research lab outside of Europe. That is not to say that research in Europe will always be lagging behind, but European universities and research centres need to concentrate on ambitious and risky goals, and then invest wisely in achieving them.

Taking your words into consideration, the EU hopes to have the first prototype of a working, 100% fault-tolerant quantum computer by 2021. Do you consider this a realistic goal?

100% fault tolerance is not a hard requirement for a quantum computer to be useful, since we already have a number of software solutions for managing this aspect of the hardware. On the other hand, prototypes already exist and are the subject of constant improvement in university institutes and corporate labs.

By 2021 we would witness even more progress, and have more exciting hardware with which to experiment. Even if we are never able to build a 100% fault-tolerant machine, the quantum computers that are going to be built would help us achieve fantastic advances in technology, and break down barriers which were previously thought impenetrable.

Quantum computing development is thus one of EU’s main priorities. The bloc already launched several important projects such as the Quantum Technologies Flagship and most recently – the OPENQKD, aimed at installing test quantum communication in several European countries. Would they be able to accelerate the industrial uptake of Europe’s scientific knowledge in the field? How?

At present, advances in quantum computing and encryption depend mostly on the quality and number of engineers working on them. If the EU invests wisely in training and supporting these experts, and then also creates the right conditions for them to thrive, soon there will be noteworthy advances in this field from Europe too. However, we should not underestimate the significance of private enterprises – a lot of the technological progress happens there too.

What other measures are needed for us to see Europe taking the lead in the quantum computing development?

Certainly, it would help having more startups and established companies take part in the race to build quantum hardware and develop the necessary software. It would take another 5 years before we enter the era of quantum computing in full swing, so there is still time to react and participate in this exciting development.

At the same time, Britain is preparing to leave the bloc. How would this affect the current and future EU breakthroughs in the field?

The UK has a quantum programme of its own, which encourages cooperation between universities and private companies. Brexit would certainly make it more difficult to collaborate across the Channel, but I hope for a post-separation future in which Britain is still an active player in the technological development of the continent.

Are there other innovation and science fields will be hindered by Brexit in case of a no-deal scenario?

The biggest downside of Brexit is the restricted flow of people and capital across the border. This would inevitably lead to a slower pace of development and adoption of technological breakthroughs. London has already promised a streamlined visa process for scientists, but any kind of division between the UK and the rest of Europe would spell disaster for scientific progress, for example by restricting access to coveted EU research funds, or making scientific collaborations impossible due to differing political agendas.

 

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Dr. Deyan Mihaylov was born in 1990 in Sofia, Bulgaria. After graduating from high school in Russe, he moved to the United Kingdom, where he earned a Bachelor’s degree from the University of Oxford, as well as Master's degree and Ph.D. in Theoretical and Numerical Cosmology at the University of Cambridge. Since September 2019 he is a Postdoctoral Fellow at the Max Planck Institute for Gravitational Physics in Potsdam, Germany.

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