Thermodynamic Geometry Through Second Order Phase Transitions

TL;DR

This paper investigates the limitations of thermodynamic geometry near phase transitions, demonstrating that minimal dissipation paths can cross phase boundaries even when traditional geometric methods fail.

Contribution

It introduces a scaling analysis and numerical methods to understand thermodynamic length and optimal protocols across phase transitions.

Findings

Thermodynamic length can remain finite across phase transitions.

Shortest paths may cross phase boundaries despite alternative single-phase paths.

Scaling laws help analyze geometric behavior near critical points.

Abstract

A common approach to quantify excess dissipation in slowly driven thermodynamic processes is through the use of a Riemannian metric on the space of control parameters, where optimal driving protocols follow geodesics. Near phase transitions, this geometric picture breaks down as the metric diverges and geodesics may cease to exist. Using Widom scaling, we analyze this framework for several universality classes and show that in some cases the thermodynamic length across the phase transition remains finite. We then demonstrate a numerical approach for computing minimal paths in such systems. We show that, in some regimes, the shortest path crosses the phase transition - even when alternative paths confined to a single phase exist.