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G. DMR 0334499 Mesoscopic effects in metal grains and quantum dots Piet Brouwer (Cornell University). Quantum interference causes two corrections to the conductance G of a quantum dot: Weak localization correction d G to average conductance < G > at zero magnetic field,
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G DMR 0334499Mesoscopic effects in metal grains and quantum dotsPiet Brouwer (Cornell University) • Quantum interference causes two corrections to the conductance G of a quantum dot: • Weak localization correction dG • to average conductance <G> at zero • magnetic field, • Conductance fluctuations as a function • of the applied magnetic field, var G dG magnetic field G varG
We considered these corrections in a dot coupled to source and drain electrodes via ballistic point contacts. I dot L Question: Do dG and varG depend on dot size L? • Known case, dot with impurity scattering: no dependence on L; • dG and var G given by random matrix theory (RMT) • With ballistic dynamics inside dot, the situation is more • complicated.
If the ballistic dynamics is chaotic: • dG depends on L • l: Lyapunov exponent of classical dynamics • tD: dwell time in quantum dot • but var G is still independent of L, • Our work • resolved conflicting • predictions for dG; • gave a semiclassical • theory of the unexpected • universality of var G • (was known from numerics). Two classes of trajectories contributing to var G: Rahav and Brouwer, Phys. Rev. Lett. 95, 056806 (2005); Phys. Rev. B 74, 075322 (2006).