Precision tests of fundamental physics

The original core activity of the Walsworth Group is the development of precision measurement tools, such as atomic clocks, and the application of these tools to precision tests of fundamental physics. From 1990 to 2010, we developed noble gas and hydrogen masers and used them to perform some of the most sensitive tests to date of Lorentz symmetry for the neutron and proton.

Our current focus is on dark matter. We are pursuing a new approach to direct detection of weakly interacting massive particles (WIMPs) below the “neutrino floor” background. We will use quantum defects in diamond to identify the direction of incident WIMPs. When a WIMP scatters in the diamond crystal, the induced nuclear recoil will create a tell-tale damage cluster, localized to within about 100 nm, with an orientation to the damage trail that correlates well with the direction of the recoil and hence the incoming WIMP. This damage cluster induces strain in the crystal, which can be measured optically via the quantum defects.

Directional Detection of WIMP Dark Matter

Our proposed approach to directional detection of WIMP dark matter is outlined in this cartoon. Left: WIMP (or neutrino) scattering event in large diamond volume is identified by conventional methods. Right: Damage track in target section is identified by optical strain mapping using NV or SiV centers distributed in the diamond at high density.