The universe began 13.8 billion years ago, but scientists are still striving to understand its origin. Zhaodi Pan, a fellow at the Department of Energy’s (DOE) Argonne National Laboratory, explores this mystery by studying the cosmic microwave background, which is the oldest light in the universe. He develops sensitive detectors that detect light from the cosmic microwave background and uses data to create 2D maps of how matter is distributed throughout the universe. He hopes his work will provide deeper insights into the history of the universe.
“Understanding the matter and energy that make up 95% of our universe is a huge puzzle.” — Zhaodi Pan
Pan began pursuing his interests in cosmology while earning a Ph.D. at the University of Chicago. After graduating, he joined Argonne in October 2020 as a Maria Goeppert Mayer Fellow. The Maria Goeppert Mayer Fellowship is an international award given to outstanding doctoral scientists and engineers to help them develop their careers in Argonne’s high-impact research environment. The fellowship honors Maria Goeppert Mayer, a theoretical physicist who earned the Nobel Prize in Physics in 1963 for her work at Argonne proposing a mathematical model for the structure of nuclear shells of the atomic nucleus. The fellowship provides early-career scientists the opportunity to pursue their own research directions, with the support of a sponsor and up to three years of funding. Fellows may also be offered long-term positions at Argonne after completing their fellowships. Here, Pan describes his research program and why he enjoys working at Argonne.
Q. What don’t we know about the history of our universe?
A. The matter that makes up all our stars and galaxies only comprises 5% of all the matter in our universe. Scientists think dark matter makes up 25% and dark energy makes up 70% of our universe, but we barely know anything about them. Understanding the matter and energy that make up 95% of our universe is a huge puzzle. Another mystery involves the origins of our universe. While we have mostly built a coherent story for its origin, one cornerstone is still missing direct evidence — the inflation theory. This theory describes how the early universe exponentially grew in size in a very short period of time after the Big Bang. Inflation explains a couple of different phenomena we have observed in astronomy and cosmology, but we need to find more evidence of it to better understand how it fits within our standard cosmological model, and ultimately reveal how our universe was created.
Q. What are your research interests?
A. I am interested in the origin of the universe and the nature of dark energy and dark matter. I believe this is the next breakthrough for physics and cosmology. There are a couple of ways to tackle these topics. One way is to use accelerators like the Large Hadron Collider to create dark matter or particles mediating its interactions with ordinary matter. Another way is to directly look into the history of the universe by studying the cosmic microwave background, which is the oldest light in the universe. The cosmic microwave background may have very faint signals that are imprints from the inflation period. I’ve been working closely with the Argonne Detector Group to develop the next generation of detectors to study these imprints in the cosmic microwave background.
Q. What is the focus of your work at Argonne?
A. The projects I work on are centered on mapping the distribution of matter in the universe and searching for fingerprints of the inflation period. The detector I’m currently working on is called a microwave kinetic inductance detector, which help map molecular emissions from gas in the universe. One advantage of this strategy is that it can detect light in a larger volume of the universe than optical telescopes, which are used to study stars. I’m also analyzing data from the third-generation camera on the South Pole Telescope, called SPT-3G, to map the distribution of matter in the universe.
Q. What inspired you to apply for this fellowship?
A. When I graduated from the University of Chicago, I was looking around for postdoctoral opportunities. Argonne, as a premier research institute, has all the things I need to push the field forward. It has a world-class clean room that can be used for detector fabrication. It has state-of-the-art supercomputers that can handle large datasets from cosmological surveys. The Argonne Superconductor Detector Group and Cosmological Simulation Group not only have the datasets, but also the resources to address the questions that I’m interested in. The opportunity to integrate into these groups and forge new research directions inspired me to apply.
Q. How has this fellowship contributed to your career development?
A. The fellowship program has provided me with a solid foundation for my career growth by enabling me to pursue my research interests and connect with a supportive community of professionals. Through the fellowship program, I have been able to pursue research and projects that would have been difficult to undertake otherwise. The support provided by the fellowship has enabled me to focus on exploring research areas without worrying about financial constraints. Networking with a diverse community of like-minded individuals, mentors and professionals has allowed me to open up new career directions and collaborations. I got many valuable insights in instrumentation development and data analysis and also broadened my scope of knowledge.
Q. What do you like about working at Argonne?
A. I like the collaborative and supportive working environment here. We have strong connections with researchers at DOE’s Fermilab and the University of Chicago, which allow us to achieve more than what a single institution could do on its own. Moreover, we have access to several state-of-the-art facilities and equipment. Our team interacts and collaborates in a way that benefits everyone involved, and I am excited about the potential for groundbreaking discoveries that will emerge from our collective efforts. I have no doubt that the collaborations around Chicagoland will produce many exciting scientific advancements over the next 20 years.
Q. What activities do you like to do outside of research?
A. I enjoy cycling, hiking and climbing in my free time. The Waterfall Glen Trail around Argonne is a good place to go!
Q. What advice do you have for others interested in following your career path?
A. Find the field that interests you the most, and then drill deeper to learn more. Be bold and be ready to embrace new challenges.
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The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.