3 research outputs found
The conductance of a multi-mode ballistic ring: beyond Landauer and Kubo
The Landauer conductance of a two terminal device equals to the number of
open modes in the weak scattering limit. What is the corresponding result if we
close the system into a ring? Is it still bounded by the number of open modes?
Or is it unbounded as in the semi-classical (Drude) analysis? It turns out that
the calculation of the mesoscopic conductance is similar to solving a
percolation problem. The "percolation" is in energy space rather than in real
space. The non-universal structures and the sparsity of the perturbation matrix
cannot be ignored.Comment: 7 pages, 8 figures, with the correct version of Figs.6-
Rate of energy absorption by a closed ballistic ring
We make a distinction between the spectroscopic and the mesoscopic
conductance of closed systems. We show that the latter is not simply related to
the Landauer conductance of the corresponding open system. A new ingredient in
the theory is related to the non-universal structure of the perturbation matrix
which is generic for quantum chaotic systems. These structures may created
bottlenecks that suppress the diffusion in energy space, and hence the rate of
energy absorption. The resulting effect is not merely quantitative: For a
ring-dot system we find that a smaller Landauer conductance implies a smaller
spectroscopic conductance, while the mesoscopic conductance increases. Our
considerations open the way towards a realistic theory of dissipation in closed
mesoscopic ballistic devices.Comment: 18 pages, 5 figures, published version with updated ref