Searches for exotic spin-dependent interactions

The existence of exotic bosons are hypothesized by a variety of theories proposed to solve the mysteries of dark matter, dark energy, the hierarchy problem, and the matter-antimatter asymmetry of the universe. Interactions mediated by such exotic bosons can be searched for in laboratory experiments by measuring spin-dependent energy shifts in atoms and molecules. We review our efforts to detect such exotic spin-dependent interactions, including a search for a monopole-dipole coupling between the mass of the Earth and rubidium nuclear spins [Jackson Kimball et al., Phys. Rev. D {\textbf{96}}, 075004 (2017)] and searches for dipole-dipole couplings by analyzing helium fine-structure [Ficek et al., Phys. Rev. A {\textbf{95}}, 032505 (2017)], studying J-coupling in deuterated molecular hydrogen [Ledbetter et al., Phys. Rev. Lett. {\textbf{110}}, 040402 (2013)], and investigating the interaction between trapped strontium ions [Kotler et al., Phys. Rev. Lett. {\textbf{115}}, 081801 (2015)].