1,675 research outputs found
Electron Dynamics in Quantum Dots on Helium Surface
We study single-electron quantum dots on helium surface created by electrodes
submerged into the helium. The intradot potential is electrostatically
controlled. We find the electron energy spectrum and identify relaxation
mechanisms. Strong in-plane confinement significantly slows down electron
relaxation. Energy relaxation is due primarily to coupling to phonons in
helium. Dephasing is determined by thermally excited ripplons and by noise from
underlying electrodes. The decay rate can be further suppressed by a magnetic
field normal to the helium surface. Slow relaxation in combination with control
over the energy spectrum make localized electrons appealing as potential qubits
of a quantum computer.Comment: Presented at Electronic Properties of Two-Dimensional Systems-1
Microwave Absorption of Surface-State Electrons on Liquid He
We have investigated the intersubband transitions of surface state electrons
(SSE) on liquid He induced by microwave radiation at temperatures from 1.1
K down to 0.01 K. Above 0.4 K, the transition linewidth is proportional to the
density of He vapor atoms. This proportionality is explained well by Ando's
theory, in which the linewidth is determined by the electron - vapor atom
scattering. However, the linewidth is larger than the calculation by a factor
of 2.1. This discrepancy strongly suggests that the theory underestimates the
electron - vapor atom scattering rate. At lower temperatures, the absorption
spectrum splits into several peaks. The multiple peak structure is partly
attributed to the spatial inhomogeneity of the static holding electric field
perpendicular to the electron sheet.Comment: 15 pages, 7 figures, submitted to J. Phys. Soc. Jp
BLOCKAGE OF AMYLOID INDUCTION BY COLCHICINE IN AN ANIMAL MODEL
Colchicine was found to have a strong inhibitory effect on amyloid induction in an animal model. When CBA/J mice were treated with colchicine concurrently with the amyloid induction regimen, the incidence of amyloidosis was, depending upon the dosage of colchicine, significantly decreased (0.005–0.010 mg colchicine per day) or completely blocked (more than 0.015 mg colchicine per day). The colchicine treatment was effective not only when colchicine was given for the entire course of the amyloid induction regimen but also when it was given only in the late pre-amyloid or the amyloid phase of the regimen or to the recipients after the transfer of amyloid. The data suggest the colchicine is effective in blocking amyloidogenesis at its final stage(s), while it may not affect significantly amyloid already deposited in the tissue
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