Mike Tarbutt

Cold complex molecules present exciting opportunities for fundamental research. Chiral molecules
are of special interest, as a measurement of a difference in energy levels between their enantiomers
can show parity violation (PV). This parity-violating energy difference can be measured by precise
measurements of vibrational transition frequencies in chiral molecules. The magnitude of the difference
in transition frequency is calculated to be about 1mHz for favourable systems, so very precise
spectroscopic methods must be developed to make the measurement. Detection of a PV effect can
also contribute to an explanation of biochemical homochirality- overwhelming disparity in chirality
of organic molecules that are found in living organisms.

The aim of the PhD project is to combine a source of cold molecules with precise spectroscopic
techniques which will allow us to measure the PV energy difference with the required sensitivity.
The chosen method for cooling molecules will be buffer gas cooling, which will provide a bright beam
of a chosen species with temperatures of a few kelvin. Development of the beam, combined with
noise immune cavity enhanced optical heterodyne molecular spectroscopy (NICE OHMS) will allow
detection of the molecules in a state selective way with a high sensitivity. Finally, with the use of
Ramsey interferometry, parity violating effects can be measured.