Louis Victor De Broglie was a French physicist who made important contributions to the field of quantum mechanics. He proposed the concept of wave-particle duality and suggested that all particles, including electrons and protons, have wave-like properties. De Broglie's work laid the foundation for future developments in quantum mechanics and had a significant impact on the field of physics. Some synonyms for De Broglie could include physicist, theorist, wave-particle duality pioneer, quantum mechanics researcher, and Nobel Prize winner (as De Broglie also won the Nobel Prize in Physics in 1929 for his work on wave-particle duality).