Quantum computers are the next step in computation. These devices can harness the peculiarities of quantum mechanics to dramatically boost the power of computers. Not even the most powerful supercomputer can compete with this approach. But to deliver on that incredible potential, the road ahead remains long.

Still, in the last few years, big steps have been taken, with simple quantum processors coming online. New breakthroughs have shown solutions to the major challenges in the discipline. The road is still long, but now we can see several opportunities along the way. For The Big Questions, IFLScience's podcast, we spoke to Professor Winfried Hensinger, Professor of Quantum Technology at the University of Sussex and the Chief Scientific Officer for Universal Quantum, about the impact these devices will have.

Among experts, what’s the current timeline they envision for quantum computers?

Winfried Hensinger: People always ask me: when are we going to have a useful quantum computer? I am always going to reply with the same answer. I am going to ask them: when do you think we had the first useful conventional computer? Some people say in the 60s, but the really clever people look to history. It was 1945. In 1945, the English Army decided the Second World War by building the first computer that could break the German Enigma code and that was arguably a reason why they could win this world war. So, you can see, in 1945 we had the first high-impact application of a conventional computer.

We really have to qualify that question, "For what applications?" For calculating projectiles or for breaking encryptions, we had a classical computer in 1945. For me to do my word processing or to get a ticket at the train station, certainly not even in the 70s. So, the same thing applies to quantum computers. In the next five or 10 years we’re going to see one first useful application for a quantum computer, and that might be a really high-impact application that will change certainly everything, maybe in one particular industry sector.

What will happen once the potential has been demonstrated?

WH: Then we’re going to build more powerful quantum computers, and not just that. We also work on the algorithms, and the software, because that is equally important for a quantum computer. The way quantum computers work is by making use of these very strange quantum phenomena and in order to really fully capitalize on these phenomena the software has to work in one particular way.

For every problem we want to solve with a quantum computer you don’t just have to have a quantum computer, you also have to write software that you also need to develop. So, what we are going to see over the next five or 10 years is people are going to more and more develop the software.

It seems like a major change from the focus on building a machine, to actually working on the different quantum algorithms – the software – to solve the specific problems we might want to solve.

WH: A good friend of mine told me that even five or 10 years ago you couldn’t even get a job at a university when you said you were going to develop quantum algorithms. That’s because nobody even felt that it was worthwhile, because people didn’t think we could build such a machine. In the next five or 10 years you are going to see plenty of new applications. We talk now about simulating molecules and drug discovery or breaking encryptions; in 10 years’ time we are going to talk about plenty more things and plenty of different things.

But let’s focus on the now. What are some exciting uses of quantum computers that are in the works now?

WH: As a company, for example, we work together with others on the first quantum computing operating system. We work with theories on solving really important problems like, for example, simulating the FeMoco molecule. That’s an example we’ve just recently worked on. The FeMoco molecule is important for nitrogen fixation and nitrogen fixation is really important when you want to make fertilizer. It turns out 2 percent of the world’s energy is right now being used for making fertilizer. If you can make nitrogen fixation a little bit more efficient, imagine how much energy you can save. That’s one problem for a quantum computer. Now we’ve just done a lot of work trying to exactly understand what the resources required for that are and we can build machines for that purpose.

I’ll give you another example. We work right now with Rolls Royce towards building quantum computers that are capable of developing better aircraft engines, and more fuel-efficient aircraft engines. This is all about fluid dynamics, and so using quantum computers to really simulate the flows inside such an engine. That will have a big impact, but we first need to start understanding what’s required and then we can streamline the development of the machines so we get there.

These are very exciting applications. Is there anything more that we can expect with these machines?

WH: You’re just going to see more and more applications like this coming through one after the other. If we’re going to have this interview in two years, in five years, or in 10 years’ time, there will be a much more powerful quantum computer than there is now. 

But there will still be many applications for quantum computers that are completely inaccessible by the machines we will have available then. We’re always going to make more powerful machines, but I think the first really cool and really interesting applications we’re going to see in the timescale of five or 10 years, and then in 20 years there are going to be yet another array of really interesting applications that will slowly grow as the performance of these machines becomes more and more powerful.

This interview was part of IFLScience's The Big Questions and has been edited for length and clarity. Subscribe to our newsletter so you don’t miss out on the biggest stories each week.