I’ve just read a great work by Jacobson, part of Berkenstein’s memorial volume, in which he quickly summarises the historical development of our understanding of entropy. I had no idea Landau hinted at non-separability in 1917, nor that Lemaitre tamed horizons!
arxiv.org/abs/1810.07839
#physics
arxiv.org
Entropy from Carnot to Bekenstein
The second half of this essay tells the story of the genesis and early development of the notion of black hole entropy, in the style of an after dinner talk (apart from a long technical footnote). The...