Boltzmann, Ludwig Eduard (1844–1906)

Austrian physicist who studied the kinetic theory of gases, which explains the properties of gases by reference to the motion of their constituent atoms and molecules. He established the branch of physics now known as statistical mechanics.

He derived a formula, the Boltzmann distribution, which gives the number of atoms or molecules with a given energy at a specific temperature. The constant in the formula is called the Boltzmann constant.

Boltzmann was born in Vienna, educated at Linz and Vienna, and held a number of academic posts in Vienna, Graz, Munich, and Leipzig. Opposition to his theories about the structure of atoms made him depressed and he committed suicide just before they became widely accepted.

A paper 1868 on thermal equilibrium in gases gave the Boltzmann distribution formula and included the constant, which has become a fundamental part of virtually every mathematical formulation of a statistical nature in both classical and quantum physics.

Boltzmann's work in the fields of gases, electromagnetism, and thermodynamics led him to consider phenomena in terms of probability theory and atomic events, which led to the establishment of statistical mechanics. This discipline holds that macroscopic properties of matter, such as conductivity and viscosity, can be understood and are determined by the cumulative properties of the constituent atoms. Boltzmann held that the second law of thermodynamics should be considered from this viewpoint.