Time: 1pm AEST - Melbourne, Sydney, Canberra, Brisbane; 3pm NZST.

Speaker: Dr Sean Hodgman
Affiliation: Australian National University


Ultracold helium atoms trapped in the first excited state (termed metastable helium) form an ideal testbed for some of the most fundamental theories of quantum physics.  I will report on our recent work at ANU testing a fundamental cornerstone of quantum physics, atomic quantum electro dynamics (QED) theory. This theory describes the energy level structure of atoms at an extremely precise level that modern experiments are now able to challenge. Such precise experiments can require revisions and extensions to QED theory to be considered, such as the recent proton radius puzzle. The simple atomic structure of helium makes it an ideal test bed for QED theory, and I will report on a number of atomic energy level measurements we have performed recently. The most important of these involves a measurement of a tuneout wavelength, where the dipole shift from all different energy levels cancels out. This makes a tuneout measurement a highly precise probe of QED, as it simultaneously tests contributions from all atomic energy levels. Our result challenges the current level of QED theory.

About Australia - New Zealand Cold Atom Seminars

This new initiative hosts a seminar once a month for the Australia – New Zealand cold atom research community.  The purpose is to encourage and facilitate ongoing discussions and collaboration in the local community.  Talks should be less than 40 minutes in length to allow ample time for questions and discussion.

Seminars will be held on the last Friday of the month (except for December) at 1pm Melbourne time (which is normally 3pm New Zealand time).  While the primary format is online via Zoom, various institutions will host the seminar in local seminar rooms.  The Zoom link is https://uqz.zoom.us/j/88604569495

You can sign up for announcements for the seminars at this webpage:

Seminars are recorded, and past seminars can be accessed from this web page.

Contact Matthew Davis mdavis@physics.uq.edu.au for further information.



Physics Annexe (06)
407 (or via Zoom https://uqz.zoom.us/j/88604569495)