Planck time
It is calculated from the Planck constant, which was first thought of by the physicist Max Planck in 1900. This work by Planck asserts that the energy of a photon is proportional to its frequency, and their relation can be put in terms of familiar units such as the joule by using the proportionality constant Planck gave us. Heisenberg's original quantum theory was improved by his teacher and colleague Max Born.