History of Quantum Mechanics

While early physicists employed mathematical formulas to explain the motion of objects, during the early decades of the 20th century, physicists began to challenge unexplained phenomena within classical physics through a subfield now known as quantum mechanics, in a quest to understand the behavior of atomic particles at the molecular and submolecular level.

Father of Quantum Mechanics

Beginning in 1900, when German physicist Max Planck showed how equations composed by physicist Ludwig Boltzmann to describe the behavior of gases, could also be used to identify a relationship between temperature and color within a filament light bulb, which in turned challenged principles that objects existed in a specific place at a specific time, with a new vision of how objects instead exist in a haze of probability fluctuating between particles and waves.

Another Genius Contributes

In 1905, Albert Einstein added to Planck’s work upon the publication of his paper, “Concerning an Heuristic Point of View Toward the Emission and Transformation of Light,” where he envisioned light traveling not as a wave, but as some manner of “energy quanta,” offering insights into the behavior of nine phenomena, including the specific colors that Planck described in his light bulb experiments.

Double-Slit Experiment

Employing Thomas Young’s 1801 double-slit experiment, by way how reproducibility, electron particles are bombarded at a board with two slits cut through it, capturing electrons on a back screen that passed through the slits. In such a manner, electron particles revealed themselves with two bright lines on the back screen, while electron waves developed interference patterns of dark and light bands, which was further validated by French physicist Louis de Broglie in 1924, when he demonstrated that electron particles could exhibit both wave-like and particle-like characteristics.

Enter Niels Bohr

During the second decade of the 20th century, Danish physicist Niels Bohr furthered the understanding of the quantum nature of atoms, when he successfully showed how electrons moved around a nucleus in orbital strata—much like planets in our solar system—jumping between orbits in response to a specific amount of applied energy.

Matrix Mechanics

Bohr’s atomic model would soon be replaced by the work of German physicist Werner Heisenberg in his “matrix mechanics” model, while, in an impressive display of parallel creation, physicist Erwin Schrödinger developed a similar theory now known as “wave mechanics,” revealing that both mathematically distinct approaches bore equivalent results, further proving that electrons obey a “wave function” that occupies “orbitals” rather than orbits.

Another Breakthrough

In 1935, Einstein teamed up with physicists Boris Podolsky and Nathan Rosen to show that two quantum particles could be set up so that their quantum states would correlate with one another, which allows quantum physicists to measure the state of one particle, which instantly reveals the state of its twin, giving a result called the EPR Paradox that Einstein called a “spooky action at a distance,” while Schrödinger later coined the term entanglement theory, making quantum mechanics, a subatomic blueprint of the macro world at large.