Ludwig Boltzmann

Ludwig Boltzmann FRS
Born	Ludwig Eduard Boltzmann (1844-02-20)20 February 1844 Vienna, Austrian Empire
Died	5 September 1906(1906-09-05) (aged 62) Tybein, Gorizia and Gradisca, Austria-Hungary
Alma mater	University of Vienna (PhD, 1866; Dr. habil., 1869)
Known for	Statistical mechanics Boltzmann brain Boltzmann's entropy formula Boltzmann constant Boltzmann equation Boltzmann distribution Maxwell–Boltzmann distribution Stefan–Boltzmann constant Stefan–Boltzmann law Maxwell-Boltzmann statistics Boltzmann–Matano analysis Boltzmann factor Boltzmann relation Canonical ensemble Detailed balance Epistemological idealism Ergodic hypothesis Equipartition theorem H-theorem Materials with memory Microscopic reversibility Phase space Softmax function
Awards	ForMemRS (1899)[1]
Scientific career
Fields	Physics
Institutions	University of Graz University of Vienna University of Munich University of Leipzig
Thesis	Über die mechanische Bedeutung des zweiten Hauptsatzes der mechanischen Wärmetheorie (1866)
Doctoral advisor	Josef Stefan
Other academic advisors	Robert Bunsen Leo Königsberger Gustav Kirchhoff Hermann von Helmholtz
Doctoral students	Paul Ehrenfest Philipp Frank Gustav Herglotz Franc Hočevar Ignacij Klemenčič
Other notable students	Lise Meitner Stefan Meyer
Signature

Ludwig Eduard Boltzmann (German pronunciation: [ˈluːtvɪç ˈbɔlt͡sman]; 20 February 1844 – 5 September 1906) was an Austrian physicist and philosopher. His greatest achievements were the development of statistical mechanics, and the statistical explanation of the second law of thermodynamics. In 1877 he provided the current definition of entropy, ${\displaystyle S=k_{\rm {B}}\ln \Omega }$, where Ω is the number of microstates whose energy equals the system's energy, interpreted as a measure of the statistical disorder of a system.^[2] Max Planck named the constant k_B the Boltzmann constant.^[3]

Statistical mechanics is one of the pillars of modern physics. It describes how macroscopic observations (such as temperature and pressure) are related to microscopic parameters that fluctuate around an average. It connects thermodynamic quantities (such as heat capacity) to microscopic behavior, whereas, in classical thermodynamics, the only available option would be to measure and tabulate such quantities for various materials.^[4]