Physical Background

Abstract

The starting point of quantum mechanics was Planck’s idea that electromagnetic radiation is emitted and absorbed in discrete amounts – quanta. Einstein ventured further by suggesting that the electro-magnetic radiation itself consists of particles, which were then named photons. These were the first quantum particles and the first glimpse of wave-particle duality. Then came Bohr’s model of an atom, with electrons moving on fixed orbits and jumping from orbit to orbit without going through intermediate states. This culminated first in Heisenberg and then in Schrödinger quantum mechanics, with the next stage incorporating quantum electro-magnetic radiation accomplished by Jordan, Pauli, Heisenberg, Born, Dirac and Fermi.