Definition of matrix mechanics
Matrix mechanics is one of the forms of expression of quantum mechanics. It was completed by Heisenberg, Born and P. Jordan in 1925. The starting point of matrix mechanics is aimed at many viewpoints in the Bohr model, such as the orbit and frequency of electrons, which are not directly observable. On the contrary, the frequency, intensity, polarization, and energy level of the spectral lines are often encountered in experiments. Heisenberg plans to create a theory that uses only the concepts of frequency, intensity, and polarization of spectral lines. His approach was influenced by Einstein's "operational definition" analysis of time and space in the theory of relativity.