Fields medallist mathematician joins Imperial

Professor Martin Hairer, who won one of maths' top prizes in 2014, brings his research group to Imperial.

It’s not just students starting Imperial this week: we also welcome a host of new staff. Among them is Professor Martin Hairer, winner of a Fields medal. The prize is awarded every four years to a handful of mathematicians under 40, and is considered one of the top prizes in the field.

We spoke to Professor Hairer about his work and ambitions for his new home at Imperial.

Welcome to Imperial - how do you feel about joining our Mathematics Department?

Thanks, I’m excited to be here and looking forward to getting started. I know a lot of the people already and it’s a nice group.

What is it you study?

I study phenomena in space and time that have some random input, which can be described by stochastic partial differential equations. These systems are everywhere – for example when you stir a cup of coffee. The movement can be described by space and time, in terms of the velocity of the movement of the coffee, but the stirring introduces a random element.

Another example described by such equations is the microscopic properties of magnets. We are used to thinking of bar magnets as having a north and south pole, but at microscopic scales all of the grains have different directions.

When the magnet is heated to a certain point, all the magnetism is lost. Just before that temperature, though, the whole magnet’s field is weaker, and it exhibits strong random fluctuations.

It’s difficult to say exactly what’s going on in this state, because the patterns of magnetic direction fluctuate more wildly the closer you look at the material. My work tries to explain what is going on in the magnet.

You won the Fields medal for your work – how did that feel?

It’s fantastic of course, but I consider myself very lucky to work in this field. One of the best things about it is that I get to meet people I wouldn’t otherwise. I get to talk to people outside my specific area and get a better overview of current work in mathematics.

What do you think are some of the most exciting area in maths today?

There are many. I would say neural networks are interesting because we couldn’t imagine them existing 20 years ago. Neural networks are the artificial information processing systems that allow for innovations like self-driving cars. Although we can make them, we don’t exactly know how they work, or for what reasons they go wrong. It’s still early days, and we can’t be sure what the maths questions will be, but I know there will be some interesting ones as it develops.