On the causality relations in thermoelectricity

The relationship between the causality principle and the existence of couplings between different thermodynamic driving forces in a given phenomenon is discussed. The case of thermoelectricity is explicitly analyzed. A transport equation for the propagation of thermal disturbances in a sample after an electric potential difference is applied is derived. The consequences of the non-hyperbolic character of this equation and the need for investigating its possible connection with nonequilibrium thermodynamics formulations are pointed out.