I need the Sheldon Cooper explanation, Please.
In the early days of the development of quantum mechanics almost 100 years ago, Louis de Broglie made the crucial conceptual breakthrough of identifying waves with particles, sometimes called wave-particle duality.
However, a crucial dilemma was not resolved. Particles are spatially stable: their size does not change as they travel, however waves do change, spreading in space and time. How can one construct a model out of the waves suggested by de Broglie that nevertheless correspond accurately to a particle?
In the 1970’s, L. Mackinnon proposed a solution by combining Einstein’s special theory of relativity with de Broglie’s waves to construct a stable ‘wave packet’ that does not spread and can thus accompany a traveling particle.
This proposal went unnoticed because there was no methodology for producing such a wave packet.
In recent years, my group has been working on a new class of pulsed laser beams that we have called ‘space-time wave packets,’ which travel rigidly in free space.
All previous pulsed fields that propagate without change have been X-shaped. It has long been theorized that O-shaped propagation-invariant wave packets should exist, but they have never been observed. Our results reveal the first observed O-shaped propagation-invariant wave packets.