# A CDE Definition

quantum mechanics

The branch of physics developed in the first part of the 20th century that was highly successful in explaining the behavior of atoms, molecules and nuclei. Developed between 1900 and 1930 and combined with the general and special theory of relativity, it revolutionized the field of physics. The new concepts, which were the particle properties of radiation, the wave properties of matter, quantization of physical properties and the idea that one can no longer know exactly where a single particle such as an electron is at any one instance were necessary to explain all of the new experimental evidence that was available at the time. For example, quantum mechanics explains the behavior of semiconductors which are used to make the myriad devices we use every day. See wave-particle duality and quantum state.

Following are the important contributors to the foundation of quantum mechanics and the principles they uncovered.

**Year Researcher Contribution**

1901 Planck Blackbody radiation

1905 Einstein Photoelectric effect

1913 Bohr Spectra theory

1922 Compton Photon scattering

1924 Pauli Exclusion principle

1925 de Broglie Matter waves

1926 Schroedinger Wave equation

1927 Heisenberg Uncertainty principle

1927 Davison & Wave properties of

Germer electrons

1927 Born Interpretation of the

wavefunction

**Before/After Your Search Term**

**Terms By Topic**

Click any of the following categories for a list of fundamental terms.