High-Precision Spectroscopy of the 2 3S1 → 2 1S0 Transition in Quantum Degenerate 4He and 3He
The standard model of particle physics is extremely successful, but we know that it is not complete. One way to discover new physics is to make extremely precise measurements of simple atoms, for which both experiments and theoretical calculations can be performed very accurately.
In my PhD research, I investigated the energy structure of helium. In our experiment, we measure the frequency (the color) of the light absorbed by a helium atom with extreme precision.
For both helium-4 and helium-3, we determined the absorption rate of the light with high precision. For helium-4, we measured the frequency with an accuracy of 0.25 parts per trillion. This is comparable to determining the distance between the Earth and the Moon with an accuracy the size of the thickness of a human hair. This measurement is the most accurate determination of an optical frequency that has been carried out in helium to date.
More information on the thesis