Abraham "Avi" Loeb is an Israeli-American theoretical physicist who specializes in astrophysics and cosmology. He serves as the Frank B. Baird Jr. Professor of Science at Harvard University, where he previously chaired the Department of Astronomy from 2011 to 2020. In 2016, Loeb founded the Black Hole Initiative at Harvard.
Loeb is a fellow of the American Academy of Arts and Sciences, the American Physical Society, and the International Academy of Astronautics.