School Seminar Program

Matterwave Interference and Inertial Sensing with Ultra-Cold Atoms

Dr John Debs
Department of Quantum Science, RSPE, ANU

Change of time to 11am Thursday 17 April directly after Hot Cross Buns in the Tearoom.

Ultra-cold, dilute atomic gases are a universal, and highly controllable test mass, making them ideal for measuring accelerations and rotations. Precise measurement of such motion has wide-spread application. For example, the precise measurement of gravity/acceleration is used in geodesy, ground water monitoring, climate science, resource exploration, and inertial navigation systems, to name a few. Fundamentally, simultaneous precise measurement of gravity on two different atomics masses constitutes a lower bound on the universality of free-fall, and more recently, atomic-based gravitational wave detectors have been proposed.

When making a measurement with photons, optical interferometry is often employed in order to vastly enhance one's measurement precision by taking advantage of the short wavelength of light and our ability to detect tiny fringe-shifts. In the same way, one can built analogous “atom interferometers” that utilise the short DeBroglie wavelength of matterwaves. Because forces such as gravity affect the matterwaves, they induce a fringe-shift on the atom interferometer at a level such that these devices already operate at state-of-the-art sensitivity.

However, all such devices to date operate with 'thermal' atoms – the analog of a filtered light bulb. Just as an optical interferometer frequently benefits from the use of a laser, our research has shown, and continues to investigate how an atom interferometer benefits from using 'atom lasers', such as a Bose-Einstein condensates (BECs). After a very accessible introduction into atom interferometers, I will highlight our studies into the use of BECs in atom-based inertial sensors, including recent work which demonstrates how using such samples can lead to significant enhancements in signal to noise. I will also discuss their attractiveness for tests of the equivalence principle.

John Debs obtained his PhD in 2012 from the Australian National University. His dissertation was on the use of Bose-Einstein Condensates in atom interferometer based inertial sensors. During his PhD, he spent 6 months at the University of Hannover, Germany, working on a cold-atom gyroscope. After his PhD, John commenced a USA Intelligence Community Postdoctoral Fellowship with the Quantum Sensors and Atom Laser group at the Department of Quantum Science, The Australian National University. Since then he has worked towards improving the performance of atom-based inertial sensors, for potential applications in inertial navigation, geodesy, and resources exploration. He is strongly involved in first-year teaching, having been recognised by the College of Science with an Excellence in Education award in 2013. His research interests include the production and studies of atom-lasers and their use in atom interferometers; the application of atom interferometers to inertial sensing and to fundamental tests such as the universality of free fall; and inquiry-based teaching methods to enhance, motivate, and inspire student learning.

Please join us for Hot Cross Buns from 10:30am in the Oliphant Building tearoom

Date & time

Thu 17 Apr 2014, 11am–12pm


Leonard Huxley Lecture Theatre Building 56, Mills Road


Staff, students and public welcome