People said this was impossible. I thought, I’ll show you
Professor Winfried Hensinger, head of the Ion Quantum Technology Group at Sussex, is on the threshold of developing technology to build the world’s first superfast quantum computer - a computer so powerful that it could solve some of the greatest puzzles of our natural environment and revolutionise our commercial world.
His latest breakthrough is the culmination of years of scientific research, but his journey really began in childhood, in front of the telly, watching Star Trek. It was then that he decided to boldly go…
From the age or four or five, I asked a lot of questions. I knew at the age of ten my future job should encompass something like being the science officer on the Starship Enterprise. I was going to invent teleportation and build technologies that change the world.
When I was in high school I started going to lectures at my local university in Ulm, Germany. Basically my physics teacher got sick of all my questions, gave me a massive book and said if you want to know more, go and sit in a university lecture. Fortunately, my friend’s dad was a lecturer there so he gave me a pile of his publications.
Athletics gave me persistence as a teenager. I was running 400 metres, which is the hardest sprint, and I used to train eight times a week. Even in the middle of winter I would break into the stadium and shuffle through snow on the track. I never give up.
What I do now is extremely difficult. Building a quantum computer is like space travel to Mars. For many years, people said this is completely impossible. That’s what got me into this field. I thought, I’ll show you.
For my PhD I worked with a Nobel Laureate, William Phillips, and he blew my mind. We were working on trying to understand quantum physics. One of the things he taught me was to ask a lot of questions. This is what I tell my students. I say, don’t trust me. Don’t trust anything. Use logic and investigate.
Quantum physics underlies everything – it’s this chair, the colour of this chair, how soft the cloth is, whether something is conducting or not conducting. But it also has these mad predictions that something can be in two different places at the same time. It’s not that half of you is here and half of you is somewhere else. You are in both places. It’s what’s called superposition.
I was the first person in the world to make an atom move backwards and forwards simultaneously. Fifteen years earlier, when I was doing my PhD, I was told it could not be done! So that made me push even harder – until it worked.
We worked around the clock – we had a sofa in the lab and took turns sleeping. You start the experiment at 8am, and things often don’t happen until 4am. After that, I decided I didn’t want to do any experiments to understand quantum physics. I wanted to build the technology.
What we are trying to do is tame quantum physics, something that no one thought was possible. There are different ways of building a quantum computer, but having looked at all the research groups around the world and what they were looking at, I thought that trapping and harnessing ions – charged atoms – was the most powerful way.
Each trapped ion is a quantum bit. Computers use bits to store information in sequences of combinations, but a quantum bit, or qubit, can hold all these combinations simultaneously, and that’s why it’s so powerful. The more trapped ions you have, the more qubits you have.
When we started we had huge ambitions, but no money. I recruited eight undergraduates and four PhD students who shared my passion. We built everything by hand, used second-hand computers and even bought equipment off eBay.
I had this deal with my students that the first day we were able to trap an ion, we would go swimming in the sea in Brighton. My students trapped an ion in 2009 in the middle of December, around 3am. Luckily, one of my students was a surf lifesaver.
Two years ago the UK government invested £270 million in quantum technology and Sussex got a share of that. That has really made a difference. All the equipment we dreamt of we could use. We were able to get rid of the crappy stuff and use state-of-the-art equipment. We pushed everything to the limit.
Our big achievement is that we have invented a new method that puts the construction of large-scale quantum computers within reach of current technology. Previously, quantum computing was realized by aligning individual laser beams onto individual ions with each ion forming a quantum bit. However, a large-scale quantum computer would need billions of quantum bits, therefore requiring billions of precisely aligned lasers, one for each ion. Now we have invented a simple method where voltages are applied to a quantum computer microchip (without having to align laser beams) – to the same effect. And we demonstrated the core building block of this new method in our experiment.
The moment we achieved this was awesome. I was at dinner and my guys called me. I went straight to the lab. Even though the signature was dodgy, I knew it was major. Now we can replicate the experiment with a beautiful signature in just a couple of hours.
We are giving this to the world for the betterment of the world. Together with scientists from around the world, and my outstanding scientists at Sussex, we are ready to make a large-scale quantum computer. We can make it happen.
- Professor Hensinger heads the Ion Quantum Technology Group at the University of Sussex and he is Director of the Sussex Centre for Quantum Technologies within the school of Mathematics and Physical Sciences. The group is part of the UK Quantum Technology Hub on Networked Quantum Information Technologies. A short film about Professor Hensinger’s work can be found here. A popular science lecture given by Professor Hensinger explaining the principles of quantum computing can be found here