Louis de Broglie was a French duke who submitted a doctoral thesis so bizarre that the physics faculty asked Einstein to evaluate it. His claim that particles behave like waves turned out to be correct and helped launch quantum mechanics.

This episode tells the story of how an aristocrat with a background in medieval history stumbled into one of the most consequential ideas in 20th-century physics.

• His proposal that all matter has wave-like properties
• Why his thesis committee was baffled and turned to Einstein for help
• How wave-particle duality was confirmed by the Davisson-Germer experiment
• His Nobel Prize and later defense of a deterministic interpretation of quantum mechanics