# Thermoelectric and thermomagnetic effects in Kaluza's kinetic theory

## TL;DR

This paper employs a five-dimensional Kaluza framework to derive constitutive equations for charged fluids under electromagnetic influence, revealing how spacetime curvature induces thermodynamic cross-effects beyond classical thermodynamics.

## Contribution

It introduces a novel five-dimensional kinetic theory approach based on Kaluza's ansatz to generalize thermodynamic flux-force relations in electromagnetic fields.

## Key findings

- Space-time curvature leads to new thermodynamic forces.
- Generalization of thermodynamic cross-effects.
- First-order constitutive equations for charged fluids.

## Abstract

A five-dimensional treatment of the Boltzmann equation is used to establish the constitutive equations that relate thermodynamic fluxes and forces up to first order in the gradients for simple charged fluids in the presence of electromagnetic fields. The formalism uses the ansatz first introduced by Kaluza back in 1921, proposing that the particle charge-mass ratio is proportional to the fifth component of its velocity field. It is shown that in this approach, space-time curvature yields thermodynamic forces leading to generalizations of the well-known cross-effects present in linear irreversible thermodynamics.