This article is part of a special series celebrating the 100th anniversary of the birth of quantum theory. Click here for more details
The seeds of quantum theory were planted in 1905 by Albert Einstein and others. However, the theory was formally constructed 100 years ago, in 1925 – as this timeline shows, it has had an impact ever since.
> 1905 In a departure from previous work by Max Planck, Albert Einstein proposes that light consists of particles with discrete energy. These “quanta of light” were early steps towards quantum theory.
> 1913 Niels Bohr develops quantum descriptions of atoms where electrons can only exist in specific orbitals with fixed energy levels.
> 1919 Physicist Hendrika Johanna van Leeuwen publishes a paper suggesting that magnetism is also a quantum mechanical phenomenon.
> 1925 On the Windswept Island of Helgoland, Werner Heisenberg performs calculations treating electron properties as sets of values rather than single values. This leads his mentor, Max Born, to discover key truths of quantum mechanics (see Carlo Robery on misconceptions about the origins of quantum theory).
> 1926 Erwin Schrödinger develops an alternate quantum framework that describes electrons as waves using a mathematical construct called wave functions.
> 1935 Schrödinger creates a thought experiment involving cats in closed boxes that can be considered both alive and dead. Einstein, Nathan Rosen, and Boris Podolski publish papers on Quantum Entanglement.
Source: www.newscientist.com