Monthly Archives: October 2017

Dark matter day and the first GPS.DM results

Well, apparently dark matter day is a thing! And perfectly timed to this inaugural event is the publication of our first GPS.DM observatory results. Happy dark matter day!

Search for domain wall dark matter with atomic clocks on board global positioning system satellites

Benjamin M. Roberts,Geoffrey Blewitt, Conner Dailey, Mac Murphy, Maxim Pospelov, Alex Rollings, Jeff Sherman, Wyatt Williams & Andrei Derevianko

Nature Communications 8, Article number: 1195 (2017)


Cosmological observations indicate that dark matter makes up 85% of all matter in the universe yet its microscopic composition remains a mystery. Dark matter could arise from ultralight quantum fields that form macroscopic objects. Here we use the global positioning system as a ~ 50,000 km aperture dark matter detector to search for such objects in the form of domain walls. Global positioning system navigation relies on precision timing signals furnished by atomic clocks. As the Earth moves through the galactic dark matter halo, interactions with domain walls could cause a sequence of atomic clock perturbations that propagate through the satellite constellation at galactic velocities ~ 300 km s−1. Mining 16 years of archival data, we find no evidence for domain walls at our current sensitivity level. This improves the limits on certain quadratic scalar couplings of domain wall dark matter to standard model particles by several orders of magnitude.

Comprehensive review on precision measurements with atoms and molecules

Search for New Physics with Atoms and Molecules

M.S. Safronova, D. Budker, D. DeMille, D. F. Jackson Kimball, A. Derevianko, C. W. Clark

This article reviews recent developments in tests of fundamental physics using atoms and molecules, including the subjects of parity violation, searches for permanent electric dipole moments, tests of the CPT theorem and Lorentz symmetry, searches for spatiotemporal variation of fundamental constants, tests of quantum electrodynamics, tests of general relativity and the equivalence principle, searches for dark matter, dark energy and extra forces, and tests of the spin-statistics theorem. Key results are presented in the context of potential new physics and in the broader context of similar investigations in other fields. Ongoing and future experiments of the next decade are discussed.

Full text for this 112 page/24 fig. review is available at arXiv ( The paper is currently under review in Reviews of Modern Physics.  Comments/corrections are welcome.