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Center for Nonlinear Studies |
The study of transport in open nano-scale quantum dots has been studied for almost two decades. Early opinions suggested that all quantum effects should be washed away upon opening the dots and any remaining structure in the conductance must be due to disorder, such as universal conductance fluctuations. But, with the availability of very high mobility heterojunction material, it was found that this view is in error. Rather, the classical phase space of such an open dot (where the defining quantum point contacts pass several modes) is mixed, and the modern understanding is connected to the decoherence theory of quantum physics. Here, many of the states undergo strong decoherence through interaction with the external environment, but other states do not couple well to the environment and remain quite robust. These latter states are thought to be the pointer states of decoherence theory. Observation of these states is found in the conductance through the dot, and this is characterized by Fano like “resonances” based in phase space tunneling to/from the pointer states. In this talk, I will discuss both experimental studies of open quantum dots, and theoretical simulations of transport through the dots.
Host: Gennady Berman