The GPS.DM collaboration analyzes navigational satellite and terrestrial atomic clock data looking for signatures of exotic physics. In particular, the collaboration searches for transient variations of fundamental constants correlated with the Earth’s galactic motion through the dark matter halo.
Our most recent results have just been published in Nature Communications (Open Access)
Cosmological observations indicate that 85% of all matter in the Universe is dark matter, yet its microscopic composition remains a mystery. One hypothesis is that dark matter arises from ultralight quantum fields that form macroscopic objects such as topological defects (see our previous post here for a brief overview of this topic).
In our recent work, we used the GPS constellation as a ~ 50,000 km aperture dark matter detector to search for such defects in the form of domain walls.
GPS navigation relies on precision timing signals furnished by atomic clocks hosted on board GPS satellites. As the Earth moves through the galactic dark matter halo, interactions with topological defects could cause atomic clock glitches that propagate through the GPS satellite constellation at galactic velocities ~ 300 km/s, as shown in the figures above.
By mining 16 years of archival GPS data, we found no evidence for dark matter in the form of domain walls at our current sensitivity level. This allowed us to improve the limits on certain quadratic scalar couplings of domain wall dark matter to standard model particles by several orders of magnitude.
Popular science articles
These serve as a nice non-technical introduction to our work.
- Science Magazine (online): Hunting dark matter with GPS data
- Scientific American: Hunting Dark Matter between the Ticks of an Atomic Clock
- MIT Technology Review: Astrophysicists Turn GPS Satellite Constellation into Giant Dark Matter Detector
- "Search for domain wall dark matter with atomic clocks on board global positioning system satellites" Nature Communications 8, 1195 (2017)
- "Hunting for topological dark matter with atomic clocks" Nature Physics 10, 933 (2014) [arXiv:1311.1244 (free download)]
- "Detecting dark matter waves with precision measurement tools" arXiv:1605.09717
See also our previous related posts:
- Search for topological dark matter with atomic clocks
- Dark matter search with GPS: Q&A
- A data archive for storing precision measurements [Physics Today]
Members of collaboration (in alphabetical order):
- G. Blewitt (U. Nevada. Reno)
- A. Derevianko (U. Nevada, Reno)
- M. Pospelov (UBC and Perimeter Institute)
- J. Sherman (NIST-Boulder)
Postdoctoral scholar(s): B. Roberts
Graduate student(s): A. Rollings, C. Dailey
Undergraduate student(s): I. Tralmer
Former members: K. Lane, M. Murphy, N. Lundholm, W. Williams
Supported by the U.S. National Science Foundation.