2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/114770In this short paper we first give a very simple derivation of the Landauer formula for a 2-point conductance of QJ $G^{2P}$, based on the uncertainty principle. The aim of this is to introduce this central equation of quantum transport to a general audience. Next we analyse the dynamics of setting up a steady-state current in a simple many-electron system and use these observations to present physical basis and formal result for the 4-point conductance $G^{4P}$, rigorously related to the non-local conductivity of an extended system consisting of electrodes and their junction.Presented at the 15th Conference of the Slovak Physical SocietyMaterials ScienceMesoscale and Nanoscale Physicstext