The inaugural Most Courageous Postdoc prize has been awarded to Daniel Bedingham, a quantum physicist at Imperial College London, UK. Miriam Frankel asks him about his unconventional career as a physicist and as an analyst for an investment bank, his research describing how the quantum realm collapses to the classical, and what winning this award means to him.

Congratulations on your award! Tell us a bit about your physics background. What did you work on during your PhD at Imperial College London and your first postdoc at the University of Sussex?

Thermal field theory, which is like quantum field theory applied to macroscopic objects like a whole gas or even the entire universe. It was interesting because it really deepened my understanding of interactions at the most fundamental level, but it wasn’t exactly foundational stuff.

Why did you decide to move into banking and work as an analyst, after your first postdoc?

At that time, I just wanted a change and I had lots of friends who worked in the financial district in London. It seemed interesting to do complex mathematics and use it for something that is highly relevant to the modern world.

You then decided to move back into research—this time into the foundations of quantum physics. Why?

I’d been thinking about it for a long time. I’d been reading lots of physics books in my spare time, such as Speakable and Unspeakable in Quantum Mechanics—a collection of papers on quantum philosophy by John Bell. I realized I could apply the mathematics that I learned for my job to problems in conceptual quantum mechanics. But it took some time to muster up the courage to go back to physics.

How easy has the transition back to research been?

I told my employers at Barclays Capital that I wanted to go back to physics and they offered me the possibility of working part-time, which was a great deal for me: I’d get to pursue what I was interested in without having to rely on getting funding. After that, I went to my old PhD advisor Tim Evans at Imperial and asked if I could be affiliated as a visitor there. That way, I could go to seminars and have an office, which makes it easier to stay disciplined.

The intellectual move wasn’t as hard as it could have been because I wasn’t under pressure to get funding, and I had kept up with quantum physics while working in the bank.

Your current research involves looking at quantum "collapse models." According to quantum mechanics, particles can hold multiple contradictory properties at the same time—for instance, an electron can be in two different places simultaneously. The state of the particle is described mathematically by a wavefunction and the orthodox line is that when an observer makes a measurement of the particle’s properties, this wavefunction "collapses" and the object takes on a definite state, with set properties—for instance, the electron will snap into one location. How do the collapse models that you are working on compare with that orthodox picture?

In these models, in contrast to orthodox quantum theory, the observer has no special role. Instead, the quantum mechanical wavefunction collapses spontaneously. The general idea is a sort of crossover between two different rules: The Schrödinger equation—the general mathematical description of the way that the quantum wavefunction evolves before it has collapsed—and the Quantum State Reduction process—which is mainly used to describe measurements. We want to come up with a composite of these two rules that doesn’t give special status to measurement. When describing a few particles, this composite should look like the Schrödinger equation, but when describing macroscopic measuring devices it should give us the Quantum State Reduction process. In particular, I’m working on making a relativistic version.

You were nominated for this award by quantum physicist Philip Pearle, at Hamilton College in Clinton, New York. He noted that you have solved an issue that had plagued other physicists working on relativistic dynamical collapse theory for a decade—describing it as a "first-rate achievement." What did you do?

In earlier attempts to make a relativistic collapse model, the vacuum became unstable and the mechanism created particles out of nowhere, increasing the energy density at an infinite rate. To prevent this, I included an unusual mediating quantum field that helped to smear out the collapse interactions, keeping the energy finite, while complying with relativity (Foundations of Physics, DOI:10.1007/s10701-010-9510-7).

Philip Pearle also noted that it’s often difficult for researchers who are working on foundational topics, a little out of the mainstream, to get financial support. Have you experienced this?

My situation hasn’t been great since I came back to physics; I’ve applied for several fellowships without success. It may be because of the topic I’ve chosen—not many people in the world work on it—but it could also be because other candidates were simply better than me. With every rejection you have to find a way to get over it and tell yourself that what you’re doing is worthwhile.

FQXi was set up to support these sorts of research projects, which may be overlooked by standard funding streams but which could have a big impact on our understanding of reality. What does receiving this FQXi award mean to you?

It’s a really nice surprise! You often hear people saying that this kind of research isn’t funded because it is "high risk." My opinion is that you should be funding lots of different topics instead of just a few. It’s definitely the lowest risk option to make sure that you don’t put all your eggs in the same basket.

Given the ups and downs of your career trajectory, would you take the same route again?

Yes! It feels like a career gamble, but it’s a life-style choice. I earn my living by working part-time in a bank instead of lecturing and I have never regretted that actual decision. But there have been times where I thought: "This is it, I should just go back to working full time!" Obviously, I’m glad I didn’t.