Not that Ludwig B. - the other Ludwig B: Ludwig Boltzmann, an Austrian physicist.
Boltzmann's name is familiar to many science students through the eponymous constant: 1.381 x 10-23 Joules/mole-Kelvin, which appears in many equations. The constant (usually written as k) arises from the proportionality between the absolute entropy of a system (S) and the number of possible arrangements of that system (W). Boltzmann's expression of the entropy, S=k ln W, is inscribed on Boltzmann’s tombstone in Vienna, Austria. Boltzmann did not write it in this form, however, Planck did.
Boltzmann also has two other equations named for him, the first is a diffusion equation used in neutron transport theory and the second describes particles in a gravitational field. In 1904, Boltzmann gave lectures on mathematics at the World’s Fair in St. Louis. He was also a popular lecturer in philosophy at the University of Vienna. Boltzmann is considered the founder of statistical mechanics, and a strong proponent of the “atomistic” view that underscored the importance of understanding the behavior of atoms and molecules in order to understand the bulk.
Loosely, the entropy is a measure of the "randomness" in a system.
2 minutes ago in Variety of Life