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R. G. Herb Condensed Matter Seminar
Quantum transport and its classical limit
Date: Thursday, October 2nd
Time: 10:00 am
Place: 5310 Chamberlin
Speaker: Piet Brouwer, Cornell University
Abstract: The interference of multiply scattered quantum mechanical matter waves causes small but noticeable corrections to the electrical conduction of a metal at low temperatures. 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. Surprisingly, the answer is not at all trivial: Whereas the interference correction to the ensemble-averaged conductance (weak localization) disappears in this classical limit, the quantum interference contribution to the sample-specific conductance fluctuations survives.

The "classical limit" is relevant for conductors in which the electron motion is ballistic and the only source of scattering is specular reflection off sample boundaries or artificial macroscopic scattering sites. In this talk, I'll outline the basic structure of a theory of quantum transport in ballistic conductors, as well as possible experimental signatures that distinguish ballistic conductors and their disordered counterparts.
Host: Vavilov
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