An interview with a quantum computing researcher

Professor Winfried Hensinger

Sussex Centre for Quantum Technologies

While heading up the Sussex Ion Quantum Technology Group and being Director of the Sussex Centre for Quantum Technologies, Professor Winfried Hensinger is working on constructing a trapped-ion quantum computer demonstrator device, a quantum simulation engine and portable quantum sensors. He is also a co-founder, Chief Scientist and Chairman of Universal Quantum, a quantum computing company.

Alongside this, Professor Hensinger is also an investigator within the Quantum Computing and Simulation Hub, which is funded through the UK National Quantum Technologies Programme - a £270M investment by the UK government to ensure the successful transition of quantum technologies from laboratory to industry. The Programme aims to create a coherent government, industry and academic quantum technology community that gives the UK a world-leading position in the emerging multi-billion-pound new quantum technology markets.

We caught up with Professor Hensinger to hear more about his work, what quantum computing could mean for everyday life and what inspired him to become a quantum physicist.

Many people are fascinated and excited by quantum computing. Why do you think this is?

I guess because it really wakes the imagination of understanding reality and nature the way it actually is. The world around us isn’t just what we see, it’s multiple dimensions and maybe parallel universes and what quantum computing does is it really invokes all of these additional facets of reality in a really mind-boggling way by making use of what we call quantum superposition – when an object can be in 2 different places at the same time. You can be sitting here on your desk and go for a run simultaneously, that’s perfectly possible in quantum physics, this feature quantum superposition is being made use of in quantum computers. I think that’s the motivation for scientists, now, the motivation for maybe the general public is the applications. Quantum computers can do certain things that even the fastest super computers in the world would take billions of years to calculate, so that really ranges across all different sectors, from gaining a new understanding of biological processes, to creating new pharmaceuticals and solving really hard problems in the financial sector. We are only just about tapping into the full potential of quantum computers, and so, I think the general public are fascinated by quantum computing because they perceive it as an extremely powerful way to solve certain problems that we’ve never solved before.

Where do you think quantum computing is at, at the moment, how far off is it? You said it’s tangible but how close are we to having this as a reality?

I’ll start by saying we have a few quantum computer prototypes in my lab right now and they operate! On the other hand, these are proof-of-principle machines, they’re very small machines and they don’t really have the capability to solve real world problems and actually no machine around the world is yet capable of doing something a normal computer couldn’t do besides one exception, the famous quantum announcement by Google, but that relates to a purely academic problem and has no practical use.

I often compare quantum computing to conventional computing. Conventional computing was arguably started in the second world war, in 1945, with the ability to crack the German Enigma code. So, we had conventional computers in 1945, yet when I was growing up in the 70s and 80s, I actually learned typewriting on a mechanical typewriter. I didn’t actually have a computer, even though they strictly existed since 1945, so quantum computers are like that, there’s not going to be one day when we have a quantum computer or when we don’t, but the machines will grow in power and range of applications and they will become smaller. First actually, they will probably stay in the cloud for a very long time and we will access them from home, but then they are going to grow in terms of their capability. I have a very personal connection to this as I did a lot of research on quantum computing in my research group in Sussex, we are now actually building quantum computing machines based on the blueprint we developed a few years ago. So, I think it’s fair to say we are now starting to build real machines and take them out of research labs and actually make a real difference.

Do you think one day we’ll all have quantum computers?

I can’t see quantum computers any time soon in our home and I don’t really see much reason either as to why you’d want to have them in the home, because you’re not going to use quantum computers for things like word processing or other standard things you use a computer for at home. You’re only going to use quantum computers when there is no computer powerful enough to solve a certain problem. So that refers to things where you don’t really need the machine at home, you can just log in via a fast web connection onto a machine that will solve the problem for you. Especially at the beginning, these machines will be very expensive and expensive to operate and as such you’re not going to just use them for any kind of problem, you’ll use it for something you really, really need to. So, I don’t think quantum computers, any time soon or probably ever, will really replace conventional computers, they, in essence, will provide a really, really powerful complementary solution to enable us to do things we couldn’t do before.

Are quantum computers superior to classical computers or just different?

I think to answer your question as concisely as I can, in the applications you will use a quantum computer for, a quantum computer is a lot more powerful than a conventional computer, but you wouldn’t necessarily use a quantum computer for every application and it would be kind of a pointless waste of resources if you were to try to. There are actually applications where a quantum computer is not even as good as a conventional computer so it really doesn’t make much sense to use a quantum computer for everything. You’d want to use a quantum computer for certain problems where you can generate a lot of impact.

Your spin out company Universal Quantum has just announced it’s received a considerable amount of funding from some of the world’s most influential tech investors – congratulations! Can you tell me a little bit more about this and what the objective is behind setting up the company?

So, I’ve been interested in building quantum computers for probably 20 years or longer, and people always told me “it can’t be done” or “it’s way too complicated” or “it’ll never happen” and all the reasons why you couldn’t do that. Whenever somebody tells me I shouldn’t be doing something I love to do it and so quantum computing is probably a life reflection of my liking of bending or breaking some rules, and so, I’ve been working on building and trying to develop quantum computers for a long time. But there is a point where you realise a university research group aren’t capable of doing the next steps which are really all about engineering, you have to have the most amazing engineers. The amount of funding required to do some of these tasks is tremendous, it cannot be undertaken with the normal research grants or normal academic research funding. So, 2 or 3 years ago I realised you really need to start a company in order to take the very next step, that doesn’t mean I’m less enthusiastic about my research group, which will keep on going and do some of the underlying research required, but the company really enables us to build the practical machines which can solve useful problems.