Quantum Transport and its Classical Limit
Prof. Dr. Piet Brouwer
(FU Berlin)
10.11.2010
The interference of multiply scattered quantum mechanical matter waves
causes small but noticeable corrections to the conductance of a metal at
low temperatures. Historically, one separates these corrections into
`weak localization', a small negative correction to the conductance
averaged over an ensemble of conductors with different impurity
configurations, and the `conductance fluctuations'. What is the fate of
quantum interference corrections in the limit that the wavelength of the
electrons becomes small in comparison to all other relevant length
scales? This limit is a "classical limit" similar to the transition from
wave optics to ray optics that occurs when the typical size of optical
elements becomes much larger than the wavelength of light. I'll discuss
the basic elements of a theory of quantum transport in this classical
limit and show that, whereas weak localization disappears in the
classical limit, the quantum interference contribution to the
conductance fluctuations remains surprisingly unaffected.