Antony Garrett Lisi (born January 24, 1968), known as Garrett Lisi, is an American theoretical physicist. Lisi works as an independent researcher without an academic position. He is a proponent of balance between scientific research and enjoyment of the outdoors.Lisi is known for "An Exceptionally Simple Theory of Everything," a paper proposing a unified field theory based on the E8 Lie group, combining particle physics with Einstein's theory of gravitation. The theory is incomplete and has unresolved problems. The theory has been extensively criticized in the scientific community.