Research Highlights

Measuring change in fundamental constants

Published online 20 October 2013

Nature Middle East

The standard model of physics treats all fundamental constants, such as the speed of light or gravity, as fixed parameters. However, several extensions of that theory may change that basic concept, allowing their values to change. Now, a team of researchers led by Michael Tarbutt from Imperial College London, including Christian Henkel from King Abdulaziz University, have placed new limits on the variations in these fundamental constants, and report their finding in last week's Nature Communications.

The team developed a method to shoot short pulses of ultracold molecules of CH and measure precisely the frequencies of the atomic transitions to 3 Hz. By comparing these results with astronomical observations of the same transitions in deep space, where the local matter density of the CH molecules is extremely different, it revealed new limits on the size of any possible variations in both the fine structure constant and the electron-to-proton mass ratio that are down to the local environment.

The findings place new limits on any possible changes in fundamental constants. With improved sensitivity in astronomical measurements, these constraints may be improved upon.


  1. Truppe, S. et al. A search for varying fundamental constants using hertz-level frequency measurements of cold CH molecules. Nature Communications (2013) doi:10.1038/ncomms3600