Some time ago a asked for a definition of thermodynamic reversibility without mentioning entropy, and some user came up with the following formal definition of a reversible process: Definition: Reversible process means that given the outside controllable mechanical, electrical, magnetic, chemica...

I've been reviewing the correspondence between Hooke and Newton, trying to understand how an object falls eastwards, as predicted by Galileo as well. I've read two things: As an object falls, it retains its original tangential velocity as radius decreases. Since there is a discrepancy between $v...

I have read this PSE post Finite Temperature Quantum Field Theory, saying that In a QFT at finite temperature, we consider the Euclidean time to be periodic, i.e. we consider a theory on the manifold $\mathbb{R}^{d−1}×S^1$, where the spatial coordinates are in $\mathbb{R}^{d−1}$ and the time coo...