Where is the shot noise of a quantum point contact?

A model to measure the nonequilibrium noise for fixed levels of source-drain current through the quantum point contact (QPC), by Reznikov et al., was discussed. It was shown that the experiments revealed the deep link between conservation principles in the electron gas and its low-dimensional, mesoscopic behavior. The analysis showed that a straightforward kinetic approach explained both constant-voltage and constant-current results, while automatically securing conservation. The central role of the electronic compressibility was also discussed for mesoscopic fluctuations.