Cold Molecules

At CCM we use cold molecules to explore fundamental physics, and we develop techniques to cool molecules to ever lower temperatures. For many years we have used molecules to measure the electron's electric dipole moment; this measurement is a sensitive test of time-reversal symmetry violation and of new physics that extends the Standard Model of particle physics. The sensitivity of the measurement is improved by slowing and cooling the molecules. We have developed cryogenic sources of cold, slow-moving molecules, and methods to decelerate molecular beams using pulsed electric fields. Now we are cooling molecules towards micro-Kelvin temperatures by applying the laser cooling methods that have been so successful for atoms. With these ultracold molecules we aim to explore the behaviour of an array of quantum particles where each particle interacts with all of the others, and we aim to make a much improved measurement of the electron's electric dipole moment.

Click here for a description of our work for non-physicists


Current Projects

 Buffer Gas Cooling

Buffer Gas Cooling
Molecules are produced inside a cell containing a buffer gas of cold helium. They are cooled by the helium and flow out of the cell forming an intense, low temperature, low velocity beam.

 Trapping & Sympathetic Cooling

Trapping and Sympathetic cooling
Trapping molecules using a microwave field and then cooling them to micro-Kelvin temperatures using laser-cooled atoms as a refrigerant.

Laser Cooling


Laser cooling and magneto-optical trapping
Using lasers to cool molecules to micro-Kelvin temperatures.


Producing ultracold YbCs molecules in a combined Yb and Cs magneto-optical trap.

Current Projects

Previous Projects

 Time-Varying Constants

Time varying constants
Measuring transition frequencies in molecules which are sensitive to time-varying fundamental constants.

 Stark Deceleration

Stark deceleration
Deceleration of molecular beams using switched electric field gradients.

Previous Projects