17 research outputs found
Universal Correlations of Coulomb Blockade Conductance Peaks and the Rotation Scaling in Quantum Dots
We show that the parametric correlations of the conductance peak amplitudes
of a chaotic or weakly disordered quantum dot in the Coulomb blockade regime
become universal upon an appropriate scaling of the parameter. We compute the
universal forms of this correlator for both cases of conserved and broken time
reversal symmetry. For a symmetric dot the correlator is independent of the
details in each lead such as the number of channels and their correlation. We
derive a new scaling, which we call the rotation scaling, that can be computed
directly from the dot's eigenfunction rotation rate or alternatively from the
conductance peak heights, and therefore does not require knowledge of the
spectrum of the dot. The relation of the rotation scaling to the level velocity
scaling is discussed. The exact analytic form of the conductance peak
correlator is derived at short distances. We also calculate the universal
distributions of the average level width velocity for various values of the
scaled parameter. The universality is illustrated in an Anderson model of a
disordered dot.Comment: 35 pages, RevTex, 6 Postscript figure
Famennian glaciation in the eastern side of Parnaíba Basin, Brazil: evidence of advance and retreat of glacier in Cabeças Formation
Symmetry of disciform scars in bilateral age-related macular degeneration.
The size of the final macular scar in subretinal neovascularisation (SRNV) is one of the most important determinants of final visual function in patients with subfoveal disease. We studied patients with bilateral macular scars from age-related subretinal neovascular membranes retrospectively in order to determine whether or not fellow eyes behave similarly. We found a significant correlation between eyes in terms of final scar size (r = 0.50, p less than 0.01). We found that 50% of fellow eyes with large macular scars (greater than 3 x 10(6) microns2) had similar sized lesions, while only 16% of fellow eyes with small macular scars (less than 0.5 x 10(6) microns2) had large scars (p less than 0.01). We discuss the significance of these findings in relation to the pathogenesis of subretinal neovascular membranes, and their implications for treatment