Hayden has contributed substantially to quantum information theory. His contributions range from quantum information approaches to the theory of black holes[2][3] to the study of quantum entanglement.[4] Hayden and John Preskill considered information retrieval from evaporating black holes. Their study of a black hole's retention time for quantum information before it is revealed in the Hawking radiation; called the Hayden-Preskill thought experiment, turned out to be compatible with the black hole complementarity hypothesis.[2]