Weekly Colloquium

Most weeks during the semester, we host a scholar for a one-day visit. The visit culminates with a public talk on a topic of contemporary physics or astronomy. Students are welcome to these talks, and seniors are required to attend at least nine over the course of a year. Near the end of each semester, honors thesis students give public lectures on their work.  For Fall 2020 these events will take place on Zoom.  

Our Astronomy program is part of the Five College Astronomy Department, which hosts its own colloquium series Thursdays at 3:45 pm at UMass. 

  • Contact colloquium organizer Alice Simmoneau with any questions about colloquia, zoom links or being added to our mailing list.

Tuesday, November 19, 2019

Tue, Nov 19, 2019

Andrew A Geraci, Northwestern: “Hunting for Fifth-Forces and Dark Matter with AMO-Based Sensors”

We normally think of large accelerators and massive detectors when we consider the frontiers of elementary particle physics, pushing to understand the universe at higher and higher energy scales. However, several tabletop low-energy experiments are positioned to discover a wide range of new physics beyond the Standard model, where feeble interactions require precision measurements rather than high energies. In high vacuum, optically levitated dielectric nanospheres achieve excellent decoupling from their environment, making force sensing at the zeptonewton level (10-21 N) achievable.

In this talk, I will describe our progress towards using these sensors for tests of the Newtonian gravitational inverse square law at micron-length scales. Optically levitated dielectric objects and optical cavities show promise for a variety of other applications, including searches for gravitational waves and dark matter. Finally, I will discuss the Axion Resonant InterAction Detection Experiment (ARIADNE), a precision magnetometry experiment using laser-polarized 3-He gas to search for a notable dark-matter candidate: the QCD axion.