According to the best information we currently have, some 85% of the universe is made up from stuff we can not see. This "dark matter" and "dark energy" seems to be governing how galaxies rotate and the way the matter distributed in the universe [1]
Extensions to the standard model of particle physics point to the existence of axions, a new class of particles that could be form some of the missing dark matter. Modelling has shown that these axions could interact with atoms in a way that mimics the action of a magnetic field [2].
This result led to the creation of the Global Network of Optical Magnetometers to search for Exotic physics (GNOME). This collaboration maintains a network of ultra-sensitive atomic magnetometers that look for exotic signals due to axions [3]. The image above illustrates an axion domain wall passing through the Earth, which could be detected and characterised by a network of magnetometers.
Our group at ANU started delivering data to the GNOME collaboration in 2020 and were a part of the first publication of data from GNOME [3]. Prior to our sensor coming online, there were no stations in the southern hemisphere. By virtue of its location, our station provides the network with much improved spatial resolution.
The same device we use in our dark matter detection experiment is also an ultra sensitive magnetometer for other effects. In particular, we are developing compact atomic gyroscopes that are insentive to magentic field noise. This would solve one of the biggest outstanding problems with atomic gyroscope technology.
Contact: Ben Buchler
[1] Particle dark matter: evidence, candidates and constraints
[2] Search for new physics with atoms and molecules
[4] Search for topological defect dark matter with a global network of optical magnetometers