Many-body effects at the world’s largest physics conference

Big Blue Bear Physicists gather in the Colorado Convention Center under the inquisitive onlooking of Denver’s Big Blue Bear statue. (Courtesy: Candice Chua) Many-body physics is the study of large ensembles of interacting particles and their collective behaviour. These systems are notoriously difficult to simulate, yet they underpin phenomena such as superconductivity and superfluidity. Thus, they are of great interest to understand. As a many-body physicist myself, I arrived at my first American Physical Society (APS) meeting with a different curiosity: understanding what the largest physics conference in the world was all about. Last week, I joined a crowd of 14,000 scientists convening in Denver, Colorado for the annual Global Physics Summit , hosted by the APS. On Sunday morning, the day before the conference, I walked alone through the streets of downtown Denver. Silence filled the frigid air. A light flurry of snow covered the empty streets in white. It seemed that the city was still asleep. But Denver was abruptly awakened on Monday morning, as I found myself well-accompanied by the crowd collectively moving towards the Colorado Convention Center for an 8 a.m. start. Inside, the conference was humming with its own emergent dynamics, with lines forming around coffee stations and people bustling to find their way to wherever they were going. Throughout the day, I was faced with the repeated indecision of choosing between over 80 simultaneous sessions. Some sessions housed APS’s infamous blitz talks with speakers racing to pack as many graphs and equations into their allotted 10 min. Having barely enough time to write down the takeaways, I tried, often in vain, to fill my memory as quickly as possible. Other sessions featured longer talks on hot topics in physics. By evening, my mind was swimming with notions of scalable quantum computing and physics funding issues and public engagement opportunities and the infiltration of AI slop into every corner of the scientific process. These sessions offered me a necessary reminder that science is not performed in a vacuum. With that said, the purely technical sessions on ultracold atomic gases served as a necessary reprieve for me that day. Ultracold atoms, cooled to only a fraction of a degree above absolute zero, provide physicists with a clean and controllable platform for studying quantum many-body physics. At its heart, this physics is governed by interparticle correlations. Seeing single atoms A fluorescence image taken under a quantum gas microscope. Each dot is one atom (Courtesy: Candice Chua) During my PhD, we measured two-body correlations and observed bosons spatially bunching together—unlike their antisocial fermionic counterparts . While the stereotypical physicist may be notoriously antisocial, the APS lanyard seemed to overturn that reputation. Over dinner one evening, I requested a table for one. Only a moment later, I was joined by a physicist I’d never met before, and the evening un