Chapter 2 - Birth of Quantum Physics: from Planck's quantum to Einstein's photon, de Broglie's wave-particle duality, and Stern and Gerlach's electron spin states

Abstract

The lives and works of the following pioneers and Nobel Laureates are described in this chapter: Max Planck (1858–1947), Louis de Broglie (1892–1987), Hendrik A. Lorentz (1853–1928), Albert Einstein (1879–1955), Clinton Davisson (1881–1958), George Paget Thomson (1892–1975), Niels Bohr (1885–1962), Werner Heisenberg (1901–76), Erwin Schrödinger (1887–1961), Max Born (1882–1975), Paul Dirac (1902–84), Otto Stern (1888–1969), Robert A. Millikan (1868–1953), and Harvey Fletcher (1884–1981). The discoveries covered in this chapter include Max Planck's discovery of energy quanta, which gave birth to quantum physics; de Broglie's matter wave duality; Albert Einstein's discovery of the photon particle in his explanation of the photoelectric effect, his relativistic length contraction and time dilation, energy and mass in relativity, experimental evidence of time dilation in muon measurements in cosmic ray showers and particle accelerator measurements, and Einstein as a pacifist; Hendrik Lorentz and his development of the Lorentz transformations, which paved the way for Einstein's special theory of relativity; the discovery of the wave nature of the electron demonstrating de Broglie's theory of wave-matter duality; the Bohr atom; Bohr and the United Nations and its efforts to achieve nuclear nonproliferation, Heisenberg's Uncertainty Principle, his complementarity argument in our understanding of the corpuscular and wave nature of atomic particles, and his efforts together with others to be the first to achieve criticality in a nuclear reactor; Schrödinger's wave function and the coordinates of an atomic electron in space and Born's interpretation of the atomic electron probability density; Dirac's prediction of the antiparticle and its subsequent discovery; Stern and Gerlach's demonstration of the spin and magnetic moments of the electron; and Millikan and Fletcher's discovery of the charge on the electron.