Joshua's Biography

My research concentrates on experimental searches for macroscopic forces beyond gravity and electromagnetism at submillimeter length scales, and tests of fundamental symmetries. One experiment, based at the IU Center for Exploration of Energy and Matter (CEEM, formerly the IU Cyclotron), is a test of the Newtonian inverse square law (ISL) at distance ranges less than 100 microns. Modifications to the ISL at short range, arising from new elementary particles or even extra spacetime dimensions, are predicted from many models that attempt to describe gravity and the other fundamental interactions in the same theoretical framework. Related experiments at CEEM test for exotic submillimeter forces coupled to spin. I also collaborate on two experimental searches for a permanent electric dipole moment of the neutron (nEDM). An nEDM signal would be an example of time reversal symmetry violation and a key to understanding the matter-antimatter asymmetry in the universe. One experiment, under construction at the Los Alamos National Laboratory, aims for a ten-fold improvement in the current nEDM sensitivity. The other, under construction at the Oak Ridge National Laboratory, aims for an additional ten-fold improvement.

Selected Publications