Rouven Essig is a theoretical particle physicist whose research focuses on the search for dark matter and other new particles and forces beyond those that are known. He has helped pioneer several concepts for detecting dark matter and other new particles with subproton masses, and he has helped create a new research program that targets low-mass dark matter and other dark-sector particles. Essig’s work draws on a range of topics in physics, including particle and astroparticle physics, cosmology, and condensed-matter physics. Although a theorist, he is co-leading several experiments searching for dark matter and new forces, including the SENSEI dark matter search experiment. (Photo courtesy of the Simons Foundation.)