Tatyana Afanasyeva

Tatyana Alexeyevna Afanasyeva-Ehrenfest (; ; 19 November 1876 – 14 April 1964) was a Russian-Dutch mathematician and physicist who made contributions to the fields of statistical mechanics and statistical thermodynamics with her husband Paul Ehrenfest.

Early life Tatyana Afanasyeva was born in Kiev , in the Russian Empire (present-day Ukraine). Her father was Alexander Afanasyev, a chief engineer on the Imperial Railways, who would bring Tatyana on his travels around the Russian Empire. Her father died while she was still young, so she moved to St Petersburg in Russia to live with her aunt Sonya, and uncle Peter Afanasyev, a professor at the St. Petersburg Polytechnic Institute.

Afanasyeva attended normal school in St. Petersburg with a specialty in mathematics and science. At the time, women were not allowed to attend universities in Russian territory, so after graduating from normal school, Tatyana began studying mathematics and physics at the Women's University in St Petersburg under Orest Chvolson. In 1902, she transferred to the University of Göttingen in Germany to continue her studies with Felix Klein and David Hilbert. and where the couple lived throughout their career.

Works in mathematics and physics Initially, Afanasyeva-Ehrenfest collaborated closely with her husband, most famously on their classic 1911 review of the statistical mechanics of Ludwig Boltzmann. The Conceptual Foundations of the Statistical Approach in Mechanics, by Paul and Tatyana Ehrenfest was originally published in 1911 as an article for the German Encyklopädie der mathematischen Wissenschaften (Encyclopedia of Mathematical Sciences), and has since been translated and republished.

The Ehrenfest model of diffusion results from her work with her husband in 1907.

Afanasyeva-Ehrenfest published many papers on various topics such as randomness and entropy, and teaching geometry to children.

Contact with Einstein Albert Einstein standing between Paul jr. and Galinka Ehrenfest outside their house in Leiden, late 1920s or early 1930s Albert Einstein was a frequent guest in the 1920s to , as evidenced by the many signatures on the wall. Later Einstein departed for Princeton University and he and Afanasyeva corresponded. The archives of Museum Boerhaave in Leiden has three letters to her from Einstein.

Afanasyeva-Ehrenfest contacted Einstein for his advice on her manuscript on thermodynamics and inquired about a translator. She wanted to give thermodynamics a rigorous mathematical foundation which was lacking and describe pressure, temperature and entropy in changing systems. Einstein responded on 12 August 1947 that he applauded her approach but he also had some criticisms:

"Ich habe den Eindruck gewonnen, dass Sie ein bisschen von logischen Putzteufel besessen sind, und dass daran die Übersichtlichkeit des Buches leide." (Translation: I have got the impression, that you are possessed somewhat by a logical polishing devil, and that the clarity of the book suffers.)

Einstein did not suggest a translator and sent the manuscript back to Afanasyeva-Ehrenfest who paid herself for its publication in 1956 as Die Grundlagen der Thermodynamik with Brill Publishers in Leiden with some, but not all of Einstein's corrections.