Designing the quantum future on a regular computer
Computer scientist Tim Coopmans uses pen, paper and regular computers to simulate the best possible quantum computer. He tells about his research and how this helps make a useful quantum computer a reality a little bit sooner. ‘I hope I will get to see quantum computers contributing something really meaningful to the world.’
Coopmans recently joined the Applied Quantum Algorithms group at Leiden University. ‘There are two types of quantum computers. In the first, you have a network of small quantum computers which can securely connect to each other. In the second, you have one big quantum computer that is capable of huge calculations, such as computing molecules and chemical reactions. One exciting example of that is fertilizer. Currently, this is produced at very high temperatures, but if we fully understand the chemical process we might be able to reduce the energy cost of the production tremendously.’
How did you get into quantum research?
Coopmans laughs: ‘I actually thought I wanted to become an experimental physicist at first. This did not turn out to be a good match. At some point, I broke a glass component and was done with it. I switched to fundamental mathematics and slowly quantum crept into the work I was doing.’
’I started working on quantum communication during my PhD. Information is stored in photons, the quantum bits, and sent through fibers. However, the chance they get lost is quite high and photon detectors and other parts of the setup can also make errors. I tried to find ways to avoid these issues by making simulations of real quantum devices that people have built in the lab on a regular computer. I would simulate multiple versions of the real quantum device and test whether I could communicate a signal through these devices, in order to predict how well they would perform in real life.’
'Someone else can have a different piece of the same puzzle and only when you come together you figure out the bigger picture.'
So you make simulations of quantum computers on classical computers?
‘A regular computer does not have enough memory to store all the information of a quantum computer. Instead, we try to focus not on storing all possible information, but only specific types. For example, if you have a single piece of paper, then a list with all the cities of the world would not fit. But if you restrict it to only cities in the Netherlands, it might just fit on that single piece of paper. In the same way, we don't simulate all the possible quantum computations, but think up smart simulation methods that work fast for relevant quantum computations only.
What do you love about doing research?
‘I like two things about research. Firstly, you get paid to figure out and learn new things, and I think that is a great thing. Secondly, what I like about theoretical research is that in principle you could do all the work by yourself, but this is often not how things go in real life. Someone else can have a different piece of the same puzzle and only when you come together you figure out the bigger picture. Everyone is so driven and intrinsically motivated, that makes collaborating very inspiring.’