Professor Bryce Gadway is the head of the Gadway Lab at University of Illinois at Urbana-Champaign. Professor Gadway and his group perform experiments on ultracold atomic quantum gases, in particular relating to quantum simulation. He recently published a Topical Review in JPhysB on Strongly interacting ultracold polar molecules, and we took some time to talk to him about his research and the field of AMO physics.
Q: Which research projects are you and your group currently working on?
We’re currently working on developing new methods to manipulate cold atoms so as to realize topologically nontrivial states of matter. The hope is to expand the range of phenomena that can be realized by cold atoms beyond what shows up naturally when they’re loaded into stationary traps or optical lattices. To achieve this, we’ve been investigating techniques based on so-called “artificial dimensions”, where field-driven transitions between discrete internal (or external) states of the atoms can mimic tunneling between sites of a lattice. The ultimate goal is to use these techniques to study emergent phenomena in interacting topological systems.
Q: What motivated you to pursue this field of research?
Part of the motivation for choosing this field of research is that it just seemed like a terribly fun puzzle to figure out how to get neutral atoms to behave in the same manner as topological electronic matter – that is, like charged electrons in a strong magnetic field or in the presence of strong spin-orbit coupling. Coming up with new techniques, and overcoming obstacles of heating and decoherence, has made this a really fun exercise. Research on topological systems was additionally very compelling from the standpoint of its intellectual merit. Emergent topological order in interacting systems, such as in fractional quantum Hall systems or quantum spin liquids, is still a poorly understood phenomena on many levels. This research topic is enriched by its connections to more general problems of disordered quantum transport, emergent behavior in systems with frustration, and nonequilibrium dynamics in driven systems.
Q: Where do you think the field is heading?
As atomic physicists, we can often control internal degrees of freedom with a much greater precision than we can external motion or external degrees of freedom. Some major goals of quantum simulation with cold atomic matter require the attainment of kinetic temperatures and motional entropies per particle that are much lower than the current state-of-the-art. Major breakthroughs in cooling gases of atoms and molecules could provide a way to explore emergent phenomena appearing at these very low temperatures and entropies. Barring such a breakthrough, one could also seek to replace external degrees of freedom – the lowest energy orbitals of tunnel-coupled lattice sites, e.g. – with a suitable set of internal degrees of freedom – e.g. some set of internal states that may be coupled with electromagnetic fields. Highly efficient methods exist for producing extremely low-entropy internal state configurations, and the simulation of nontrivial phenomena could be allowed by constructing an artificial “kinetic Hamiltonian” in the internal degrees of freedom. There are quite a few caveats related to this approach, but for some systems having transitions immune to technical noise, this could be a very powerful approach to circumventing one of the main challenges facing cold atom and cold molecule research.
Q: What current problem facing humanity would you like science to provide a solution to?
Ideally science will continue to provide solutions to issues of sustainability related to the availability of food, water, and natural resources for a growing population, and the challenges associated with climate change.
Q: What do you find to be the most rewarding aspect of your job?
Getting to work with smart and enthusiastic young researchers, who bring in a lot of fresh energy and ideas, definitely helps to make it enjoyable to go to work each day. The rewarding aspects are getting to see the ideas that we develop take shape in the lab, and seeing the development of the students as they become independent researchers.
Q: If you were a young physicist just starting out today, what would you study?
I would probably either still take up research in AMO physics – it’s just such a fun and intellectually diverse field – or perhaps biophysics.
On behalf of JPhysB I would like to thank Professor Gadway for answering our questions and for recently publishing Strongly interacting ultracold polar molecules in Journal of Physics B. You can also find out more about his group’s research here.
This work is licensed under a Creative Commons Attribution 3.0 Unported License
Image 1 and front image: copyright Bryce Gadway; used with permission.