Louis-Victor de Broglie

b. 15 August 1892

d. 19 March 1987

Noteworthies:

• Nobel Prize laureate
• Fellow, Académie française
• Perpetual Secretary, Académie des sciences
• 7th Duke of Broglie
• Fellow, Royal Society of London for the Improvement of Natural Knowledge

Born into a rich, aristocratic family, de Broglie (pronounced /də'brɔɪ/) had really no need to become a physicist, or anything else for that matter. His interest in physics came as a combination of natural intuition and skill in the subject and (most probably) from the influence of his older brother, Maurice, who was an accomplished physicist himself. However, his entrance into the field was as well-timed as it was risky.

The last thirty years of science had been revolutionary. Einstein had recently declared light to possess characteristics of both waves and particles, introducing what is now known as wave-particle duality. Planck and Bohr followed up with the discovery of quantization, which is the simply but profound idea that waves (bound energy) can exist only in certain, specific denominations, between which energy propagation is non-existent. Since before, physics had been divided into two separate domains -- particle physics, and wave physics -- duality was something of a hot topic that caused frequent debates. Bohr even refused to believe the results of his own experiments, trying force his findings to fit a (consequently incorrect) model that he couldn't give up.

I know it may seem like a trivial thing to us, but this was groundbreaking work that seemed to be trying to convince the world that apples and oranges were the same thing. De Broglie found himself in the middle of a great schism with Einstein on one side and Bohr on the other. A wrong step could end any credibility he had gained and potentially end his career. Slamming together some of the most basic equations (E=mc² and E=hν), he boldly declared the impossible, initially based on intuition and faith that not only was light duality correct, but that all things exhibited such a behavior. Sometimes light acts like a particle and sometimes like a wave. It is, however, neither of the two by the classical definition. Even more surprising, sometimes matter behaves like a particle, and sometimes like a wave.

In other words, you have a wavelength. So does a grapefruit. And your car. At the right speed and in the right conditions, a stream of grapefruits would diffract around a corner exactly like a water wave does. At a large scale, this doesn't mean a darned thing. But on the scale of atoms and electrons, duality lies at the heart of basically every modern invention in the world today. Computers function because we understand how to control electrons because we finally figured out the they weren't little tiny balls bumping into each other and flowing along, but could instead be treated as a wave. There are hundreds and hundreds of applications stemming from duality that I could mention, but even if semi-conductors (things that help make computers go) were the only thing ever invented because of de Broglie, can you see the implications of his work? What doesn't use a computer to help it function?

The science here is too deep for me to go into (or even understand myself). But that's kind of a blessing because I'd rather focus on the lessons learned from de Broglie as he discovered these principles. He was under immense pressure not to believe in duality. He very easily could have embarrassed himself and his family (particularly devastating to a French aristocrat) and ended his career. On a simpler note, he could have dismissed his intuition as passing insanity and focused on what everyone else forced themselves to see just because that was what they had always believed. Instead, de Broglie challenged and followed his own ideas, discarding the false ones along the way, and became one of the founding fathers of modern physics and the technological age in which we live. His work demonstrates genuine curiosity and courage and is a perfect example of the true scientific method.

Source: Cropper, William H., Great Physicists. New York : Oxford University Press, 2001.