Quantum Point Contacts and Beyond: New Results on Mesoscopic Conductance   and Fluctuations
  We summarize the main results of a microscopically based kinetic theory, applicable to open quantum point contacts (QPCs) driven up to high fields. The governing role of gauge invariance -- and the many-body sum rules for the electron gas -- lead to stringent constraints on both transport and fluctuations. These constraints exert a dominant influence on the observable properties of QPCs and similar open mesoscopic conductors. We illustrate this in the context of certain predictions within purely phenomenological models of mesoscopic transport. 
Mukunda P. Das, Frederick Green, and Jagdish S. Thakur