Leading experimental physicist David DeMille joins Johns Hopkins

World-leading atomic, molecular, and optical (AMO) physicist David DeMille is looking for new particles and forces that could answer fundamental questions about the universe and solve some of the greatest mysteries of cosmology.

DeMille, who recently joined Johns Hopkins University as Bloomberg Distinguished Professor of Atomic/Molecular Physics and Precision Measurement, is known for his groundbreaking work in the field of experimental physics. He has developed novel methods of precision measurement to probe for the existence of new particles and forces that exist outside the standard model of particle physics, the theoretical framework that explains the most basic known building blocks of the universe and the forces that govern it.

"We know that there are particles and forces that exist outside of this framework from observations made in cosmology," DeMille explains. "The most famous example of this is dark matter, which holds galaxies together more strongly than we can explain based on the physical matter that we see in the galaxies. However, none of the particles or forces in the standard model of particle physics have the properties that would explain this."

About the BDP

• Name: David DeMille
• Title: Bloomberg Distinguished Professor of Atomic/Molecular Physics and Precision Measurement
• Appointments: Department of Physics and Astronomy, Krieger School of Arts and Sciences; Research and Exploratory Development Department, Applied Physics Laboratory
• BDP cluster: Hub for Imaging and Quantum Technologies
• Previous role: Department of Physics, University of Chicago
• Education: AB in Physics, University of Chicago; PhD in Physics, University of California, Berkeley

Most of DeMille's research, however, has been focused on solving a different mystery: the matter-antimatter asymmetry. According to the standard model of particle physics, the energy from the Big Bang should have created equal numbers of matter particles and antimatter particles. Matter and antimatter particles are always produced as a pair, and every particle seen in nature has an antimatter counterpart that has the same mass, but opposite charge. If a particle and its antimatter counterpart come together, they annihilate one another, releasing energy. Yet, according to DeMille, the universe is made up almost entirely of matter, but very little antimatter.

"There's a deep mystery behind the imbalance of matter and antimatter in the observable universe," DeMille says. "Somehow, some of the matter particles created during the Big Bang survived and turned into what we see today. Everything we see around us is a remnant of a tiny difference between matter and antimatter after the Big Bang that we don't understand. Explaining this requires some kind of new force or new particle that is not described in the standard model of physics. That is what drives a large part of my work."

DeMille, who comes to Johns Hopkins from the University of Chicago, brings his combined experimental and theoretical experience to Johns Hopkins as part of the Hub for Imaging and Quantum Technologies BDP Cluster. DeMille has pioneered techniques for manipulating quantum states of molecules and uses these methods in the search for evidence of new particles and forces with properties that would explain the matter-antimatter asymmetry. He looks forward to continuing his work at Johns Hopkins.

"There's a growing sense in the field of particle physics that we need new approaches in order to find new particles that we know exist but have yet to see and whose properties are mostly not yet known," DeMille says. "Hopkins has committed to the idea that these are the future of particle physics in a way that is almost unprecedented. The combination of existing expertise of particle theorists here, along with a powerful set of technical resources, will make it possible to make progress faster and to try more interesting ideas than have ever been possible before. There is also a close link, technically, between these types of particle physics-motivated experiments and many emerging quantum technologies. So having a community of folks within the Hub for Imaging and Quantum Technologies BDP cluster, working on so many closely related topics, is going to be powerful in both directions."

Says Ralph Semmel, director of the Johns Hopkins Applied Physics Laboratory: "David DeMille's pioneering research in molecular systems and precision measurement have exciting cross-over applications to quantum sensing and quantum computation, two strategically critical domains the laboratory is currently exploring. We are very excited about the expertise that he brings to Johns Hopkins, and eager to explore these and other opportunities where his work can contribute to APL's cutting-edge research and development."

Adds Christopher Celenza, dean of the Krieger School of Arts and Sciences: "Our scientists are leading the way toward a deeper understanding of some of the mysteries behind particle physics. I am elated that Professor DeMille is joining us, bringing his novel expertise and experience to propel this work forward and help position Johns Hopkins as a trailblazer in atomic, molecular, and optical physics."

As a Bloomberg Distinguished Professor, DeMille joins an interdisciplinary cohort of scholars working to address major world problems and to teach the next generation. The program is supported by Bloomberg Philanthropies.