” The Heisenberg-Bohr concepts leave us all breathless, and have made a deep impression on all theoretically oriented people.” -Albert Einstein, 1926
The period 1905 to 1925 was a great time for the world’s leading physicists in the race to understand the quantum nature of matter. To explain so many curious and undigestible phenomena about radiation, atoms, molecules and solid materials, some groups worked together and sometimes compete with another. The climax happened around 1925 when the structure of quantum mechanics was finally laid down.
This started with Louis de Broglie‘s conjecture in 1924 that particle-like objects such as electrons should display wave properties. Indeed if light which is initially thought to be a wave can behave as a particle or quantum, why not those objects which we normally conceive of as particles display wave-like properties? Why not indeed?
Shortly after de Broglie introduced his concept of matter waves, Erwin Schrodinger proposed an answer to the question of what happens to the matter waves when a force acts on it. He came up with a wave equation now known as Schrodinger’s Equation that lies at the heart of quantum mechanics.
Given a particle and the force that acts on it, Schrodinger’s equation gives the possible waves associated with this particle at a given position and time. And this is designated by the hardest working symbol in modern physics: the wave function .
That Schrodinger would be mistaken in the physical interepretation of the wave function is only one of the many curious twists in this very interesting and engaging conversation. What took Max Born to interpret the absolute square of as probability density for finding electrons and not matter density as Schrodinger intimated?
Months before Schrodinger was to write down his famous equation, Max Born, with his young students Werner Heisenberg and Pascual Jordan, already created an entirely different approach from that of Schrodinger. The matrix formulation of quantum mechanics developed by Born’s group in Gottingen, Germany described matter and radiation as discrete particles.
The two formulations of quantum mechanics were thought to be different but they were quickly proved to be equivalent by Schrodinger himself. Soon thereafter, Paul Dirac incorporated the special theory of relativity with quantum mechanics and the ‘quantum field theory’ was born.