A Contact Topological Glossary for Non-Equilibrium Thermodynamics
Michael Entov, Leonid Polterovich, Lenya Ryzhik
TL;DR
This work develops a geometric framework for non-equilibrium thermodynamics by encoding thermodynamic equilibria as Legendrian submanifolds in a jet-space (extended and reduced) phase space and interpreting non-equilibrium transformations as non-negative paths or Reeb chords. It establishes a direct link between slow, quasi-static evolutions (non-negative Legendrian isotopies) and ultrafast processes (Reeb chords), with a partial order on Legendrians encoding thermodynamic constraints. The authors provide general theorems connecting slow global connections to the existence of ultrafast, energy-non-increasing jumps and illustrate the theory with explicit ultrafast processes in ideal-gas/Stirling-like settings and Curie-Weiss magnet models, deriving chord conditions and energy implications. The results offer a topological toolkit for analyzing non-equilibrium thermodynamics and suggest experimental interpretations for ultrafast transitions, including Stirling-engine segments and magnetic demagnetization phenomena.
Abstract
We discuss the occurrence of some notions and results from contact topology in the non-equilibrium thermodynamics. This includes the Reeb chords and the partial order on the space of Legendrian submanifolds.
