Physics

Theoretical physics is the search for compelling mathematical descriptions of the world around us, and it has been extraordinarily successful.  We have discovered the equations that govern the flow of electrons in a computer chip and the flow of air over an airplane wing, we can describe what happens deep inside the atomic nucleus and the evolution of the universe on the largest scales.  But what about us?  Can we imagine writing equations that describe how our brain makes decisions, or how a single cell develops into a complex organism?  Creating a “physics of life” is a daunting task, but there has been exciting progress. 

Fundamental physics (including physics beyond the Standard Model) can be tested using table-top precision measurements. The talk will describe measurements of the size of the proton, the fine-structure constant and the electric dipole moment of the electron. Two recently completed measurements will be described. For the first measurement, the n=2 Lamb shift of atomic hydrogen is measured, allowing for a new determination of the charge radius of the proton. This determination is crucial to resolving the decade-old proton radius puzzle, in which it appeared that the proton radius took on a different value when measured with muons compared to measurements using electrons. The second measurement is of the n=2 triplet P fine structure of atomic helium, and this work is part of a program to obtain a new determination of the fine-structure constant. Both of these measurements use a new measurements technique: Frequency offset separated oscillatory fields. Finally, a new major effort (EDM^3) is starting at York University to measure the electron electric dipole moment using polar molecules embedded into inert-gas solids. This measurement will test for T violation and will probe physics up to the PeV energy scale.