John Doyle sees opportunities for science — and APS — in the year ahead

Between running an ultra-cold molecular research lab, co-leading Harvard University’s Quantum Science and Engineering Initiative, and now serving as the 2025 APS president, John Doyle has had a lot on his plate.

But Doyle stays motivated thanks to “the community, the science, and the incredible scientists that are working every day to pursue this exciting work,” he said. “If there's something I can do to support that, then I feel invigorated and energized.”

Doyle, also the former chair of the APS Topical Group on Precision Measurement and Fundamental Constants, brings a wealth of expertise to the APS Board. He holds a bachelor’s degree in electrical engineering from the Massachusetts Institute of Technology, where his experience working in an atomic and condensed matter physics lab as an undergraduate motivated him to earn a Ph.D. focused on ultracold atomic hydrogen, also from MIT. After working as a researcher at AT&T Bell Laboratories and MIT, he joined the Harvard physics department in 1993, where he is now the Henry B. Silsbee Professor of Physics.

Doyle spoke with APS News about his journey into the field of atomic, molecular, and optical physics and the opportunities he sees in the coming year for science and for APS. This interview has been edited for brevity and clarity.

Tell us about your academic journey and how you got interested in physics.

I went to MIT as an undergraduate. I started majoring in computer science, but at MIT everybody has to take physics. I was lucky enough to have this influential instructor in my first physics class, Dan Kleppner. His explanations were super clear, and whenever he could, he threw in a joke. That experience made it feel like physics has a human side to it, that you could have fun while you're doing things which are very mathematically oriented.

What got me hooked on physics was working in a lab co-led by Kleppner and Tom Greytak with an amazing postdoc, Harald Hess. The idea was to make a Bose-Einstein condensate out of atomic hydrogen. The fact that you could make a gas out of atomic hydrogen was amazing to me, but also, the idea that you could produce a macroscopic quantum fluid using techniques which were a combination of atomic physics and cryogenic condensed matter got me very excited. And, of course, there's the fun of working with cryogenics.

What research questions interest you and your group?

I work in two areas, both of which involve creating cold or ultra-cold molecules and then detecting the molecules using laser spectroscopy. These molecules are powerful tools, not only to develop new quantum information systems but also to answer fundamental questions about particle physics and cosmology.

One of the things we're interested in is answering the question of why there is a matter-antimatter asymmetry in the universe. There are many theories that look good, but we don't really have the microscopic candidate — the particle source of what we call charge parity violation — that's needed to describe this asymmetry.

Generically, there is predicted to be a particle with enough CP violation. If that particle exists, it can be sensed by the electron or proton or other fundamental particles and endowed with an electric dipole moment. If we see this electric dipole moment, we can directly say that a particle exists and could explain the microscopic origins of matter-antimatter asymmetry.

Another overarching theme in our work is quantum control — being able to put an atom or molecule into any quantum state you want, then couple molecules together and use those as a quantum information processing system. How big a molecule can you make ultra-cold and control the internal quantum state? This is an interesting question of complexity.

Are there major findings, either from your group or the broader field, that you feel have elevated atomic, molecular, and optical physics research?

One recent exciting finding is that we can have full quantum control over a triatomic molecule — we can put it in any quantum state, rotational state, or vibrational state. We can also make optical tweezer arrays of individual polyatomic molecules, where we use light beams to hold individual molecules. This means we can not only determine their internal quantum state — we can also hold them in space very precisely.

Another exciting finding — not from my group — is making more precise optical atomic clocks, using lots of atoms held in egg carton potentials of light. I point this out because the precision of these clocks has been getting better, Moore's-law-style — where every few years, the precision doubles. If you look in the past in physics, clock precision is a bellwether. Being able to make measurements more precisely will feed into other science or technology. We can have confidence that the field of AMO will be healthy for another decade or two, at least.

How did you first get involved with APS?

I first came in contact with APS, as many members do, as a graduate student. At that time, I took APS for granted — that this organization existed, it was run well, it ran meetings, and we had our research findings that we would submit to APS journals. In a sense, it’s a sign of a healthy organization when the students take it for granted that everything is functioning well.

One reason I stood for election was that I realized that we shouldn't take things for granted, that there's work that goes into all the important activities that APS does: our lobbying in Congress, setting of policy, standards for the field, outreach. I felt that I should do my part to keep this great organization going and running so well.

What are your goals while serving as APS president?

One thing I'm excited about is the International Year of Quantum Science and Technology. Quantum mechanics is one of the foundations of modern science. It also has mysterious-looking aspects that can get young people excited and has been talked about a lot in the media and entertainment, so the soil is there to grow excitement among young people for doing science.

We're also hosting the Global Physics Summit in March. The summit has a record number of abstract submissions, and it will have satellite sites — more than ever before — where physicists and aspiring physicists will join from around the globe, so this meeting is an opportunity to promote science more broadly.

We should also focus on maintaining and improving our publishing. One of the things that open access publishing models have driven is getting researchers to think in new ways about the best place to publish a paper. We want researchers to understand that if you publish in APS journals, which are purpose-led, everything that goes into our organization is for the good of science.

What challenges lie ahead, either for APS as an organization or for the scientific community a whole?

Funding for research is getting tighter, and that's a challenge we all feel. Finding new ways to support physics and help researchers do their best is only going to grow in importance.

It's no secret that public trust in science has taken some hits recently. I'm interested in exploring how we can expand our work to connect with people, to share the amazing work that physicists are doing, and to let people at all levels know that physics is having an impact on their lives.

What do you see as the opportunities ahead?

The problems we face today are huge, but not unprecedented. What is unprecedented is the opportunity to connect more broadly. Language barriers are eroding, and there's a growing cultural commonality, especially among young people.

APS plays a very active role in communicating to our elected leaders and to the public about why physics is important — our policy is truth, and we tell the truth about science. Truth is our superpower, and we should speak out about science, even when the climate is a difficult one. We make that our most important focus whenever we're discussing issues of importance to the country.

This is an amazing time for science and physics. We're lucky to be alive when so many ideas are being developed — so many new techniques and connections to other sciences. It's extremely exciting.

Get involved in the future of physics and advance your career by becoming an APS member today.