Events at Physics

<< Fall 2023 Spring 2024 Summer 2024 >>
Subscribe your calendar or receive email announcements of events
Atomic Physics Seminar
Using precision measurements to study the interplay of quantum mechanics and gravity and explore the universe
Date: Monday, February 19th
Time: 12:00 pm - 1:00 pm
Place: 5310 Chamberlin Hall
Speaker: Tejas Deshpande, Northwestern University
Abstract: Gravity is the least understood of the four fundamental forces at a microscopic level. Moreover, quantum phenomena are typically challenging to observe in macroscopic systems. An overlap between gravitational and quantum phenomena is expected to occur at very high energies like those inside a black hole or close to the big bang. Precision measurements offer an alternate low-energy route to studying such phenomena in tabletop experiments. Furthermore, precision measurement tools can be used for cosmic exploration through detection of gravitational waves (GWs) and direct detection of dark matter (DM). In this talk, I will discuss three current experiments aiming to investigate such phenomena of great importance to fundamental physics research. The first experiment involves performing light-pulse atom interferometry (LPAI) over a 100 m vertical baseline and is part of an international collaboration called Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS). I will discuss the work done by our group at Northwestern University (NU) on the design, construction, and testing of the laser system for MAGIS. I will present empirical and simulation results demonstrating the potential of MAGIS to detect GWs and ultralight DM at mid-band frequencies (0.03-3 Hz) with unprecedented sensitivity. Moreover, I will discuss how MAGIS can study macroscopic quantum phenomena by creating quantum superpositions of massive systems separated by tens of meters. The second experiment aims to use LPAI to measure Newton's gravitational constant, to a precision of less than 10 parts per million, using a 2 m vertical baseline at NU. I will present some recent results from the first stage of the NU apparatus utilizing resonant LPAI, with a record 504 loops, and discuss its implications for MAGIS. The third experiment involves detecting ultralight DM using cryogenic Fabry-Perot cavities at NU. I will conclude with some ideas for near-future experiments which aim to study the interplay of quantum mechanics and gravity using a combination of technologies associated with LPAI, laser interferometry, and kilogram-scale levitation.
Host: Thad Walker
Add this event to your calendar