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Community Profile: David Weir

Name: David Weir

Current position: Faculty

Affiliation: University of Helsinki

Field of research: Numerical methods for early universe cosmology; simulations; lattice Monte Carlo


What is your career trajectory to date?

I started as an undergrad in Edinburgh in 2002, before dropping out and moving to London, where I studied at Imperial right through to my PhD. I finished my PhD in 2011, and then moved to Helsinki, Finland to start a postdoc. After three years in Helsinki I ended up in Stavanger, Norway as a Marie Curie intra-European Fellow. I returned to Helsinki in 2016, before getting a five-year Ernest Rutherford Fellowship in Nottingham, moving back to the UK in early 2019. My time in Nottingham was short-lived, however, as I was fortunate enough to get a tenure track job back in Helsinki, which I started in the autumn of that year.

What are the most exciting open questions in your research area?

Thinking quite specifically about my immediate research field, I think the exact nature of turbulence after an early universe phase transition is interesting. Correctly getting a handle on it takes a range of analytical and numerical skills and working with really cool people.

What do you like and dislike about being a scientist?

I like the teamwork, the problem solving, the meeting new people, and helping others learn new skills and develop themselves. Discovering new things, or figuring things out as part of a team is a wonderful feeling.

I’m not so keen on the endless rankings, metrics and performance measures that have become a part of academia over the past couple of decades. The overt sexism and other discrimination that our colleagues face even today drives me up the wall, as do the subtler acts of discrimination that mean we lose many great scientists because they’re made to feel they don’t (or won’t) fit in.

Which of your skills are you most proud of, or find most useful?

I’ve realised that the most fun thing about science – and the most challenging thing – is working with different people. I think I could do a lot better at it, but actually talking to people and making sure they have what they need to do science is by far the most fun I have on a daily basis.

In your career so far, at what point were you the most excited, and what were you excited about?

There was a point in the middle of my first postdoc where I was working on studying gravitational waves from first-order phase transitions. It was a change of field for me, and I wasn’t sure if there was anything interesting to see. But one day the simulation results came back, and it soon became clear that what we were seeing did not match the theoretical modelling of the time. It felt like a turning point; we saw a phenomenon in our simulations that was previously unknown. It was also the fulcrum on which my career pivoted; until then I wasn’t too sure what kind of simulations I wanted to do, or whether anyone would hire me to do them. That result, once published, would help to change that.

What new skills would you like to learn in the next year?

I want to get better at time management! It feels like it’s the job of a lifetime, but I would like to at least try. On a more technical level, a lot of people are now using multiple graphics processing units (GPUs) for parallel simulations; I want to get better at writing code for them – while also keeping the learning curve as shallow as possible for my early-career colleagues.

What advances or new results are you excited about or looking forward to?

I’m looking forward to improved constraints on (or evidence for) gravitational waves from pulsar timing arrays, and to future gravitational wave detectors like LISA and TianQin.

What is the biggest obstacle that is slowing down your research field right now?

Science is (still) overrun with people with a lot of privilege, like me. Our field – particularly the area of numerical methods in theoretical physics and cosmology – needs to become a lot more diverse and welcoming to people of all backgrounds. That way we will recruit more of the best people and hopefully keep them around to lead our field in the future. Efforts to improve this need to be wired in at every career stage from kindergarten to 5-year fellowships, and I don’t think we’ve gone nearly far enough at any of these stages.

What role do you think a community network like EuCAPT can play in developing theoretical astroparticle physics and cosmology in Europe?

The great thing about EuCAPT is how it has managed to cultivate a sense of community entirely virtually, and I am excited to see that continue.

We are all becoming more aware of the heavy burden on the environment from the academic lifestyle of endless travel (not to mention the strain it places on us, our relationships and those for whom we have caring responsibilities). It’s unfair on our peers and on the environment to pretend that in-person events with no possibility of remote participation should be the norm. The pandemic only serves to strengthen this argument. I hope EuCAPT will continue to innovate in finding ways to connect scientists – without returning us to endless time spent on aeroplanes away from our loved ones.

What’s your favorite food?

How the rest of the world survives without Finnish rye bread is a mystery to me. Karelian pasties are also delicious. I even like Mämmi. Basically, if it’s from Finland and made from rye, it’s probably good.

Have you lived in a different European country than you do now? If so, would you like to tell us something about it, e.g. a fond memory or something you found surprising?

I grew up in Scotland, studied in London, but my academic career since my PhD has been in the Nordics. From Scotland, I miss the mountains and the people; from London, I miss the sheer liveliness of the place. But I’m very happy in Finland and couldn’t think of anywhere I’d rather work.

How do you like to relax after a hard day of work?

I enjoy reading, especially poetry: I’m a fan of Jackie Kay, Norman MacCaig, Edwin Morgan (all the Scottish poets I rolled my eyes at in high school; turns out they’re quite good actually). I also like baking tasty things.

Do you have any non-physics interests that you would like to share?

Over the past couple of years I’ve taken a lot of pedagogical courses and it’s completely changed how I view not only my teaching but also my entire field. It has given me a vocabulary to describe the inequities I see in higher education, the tools to make my pedagogy more inclusive, and the motivation to reflect on my own teaching, research and leadership activities.

Less directly related to my work, I enjoy going for hikes (in the Finnish forest or the Scottish mountains).

If you were not a scientist, what do you think you would be doing?

I think a lot of my non-physics experiences that could influence my answer here are a result of where physics has taken me. But if I could see myself working anywhere else, it would be in conservation: understanding the land and what grows and lives on it, interpreting it for others, and making people feel a sense of belonging and understanding of their environments.

What do you hope to see accomplished scientifically in the next 50 years?

I’ve decided to make this list about science in general, and to be realistic about what might happen (so, no direct detection of magnetic monopoles, no matter how cool that would be). I’d like to see an understanding of the pathogenesis of dementia, including Alzheimer’s disease – and, related, perhaps – the folding behaviour of proteins. A resolution of the Hubble tension, and (again, maybe related) an elucidation of dark matter and dark energy. An explanation for the baryon asymmetry of the universe would be nice, too.

What question would you have liked us to ask you, and what would you have responded?

Where do you see yourself in five years is always a good one, right? And I’d answer – right here in Helsinki having fun, learning about the early universe, and working with and teaching wonderful people.


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