580 research outputs found
Error-Correcting Codes for Automatic Control
Systems with automatic feedback control may consist of several remote devices, connected only by unreliable communication channels. It is necessary in these conditions to have a method for accurate, real-time state estimation in the presence of channel noise. This problem is addressed, for the case of polynomial-growth-rate state spaces, through a new type of error-correcting code that is online and computationally efficient. This solution establishes a constructive analog, for some applications in estimation and control, of the Shannon coding theorem
Analytical Continuation Approaches to Electronic Transport: The Resonant Level Model
The analytical continuation average spectrum method (ASM) and maximum entropy
(MaxEnt) method are applied to the dynamic response of a noninteracting
resonant level model within the framework of the Kubo formula for electric
conductivity. The frequency dependent conductivity is inferred from the
imaginary time current-current correlation function for a wide range of
temperatures, gate voltages and spectral densities representing the leads, and
compared with exact results. We find that the MaxEnt provides more accurate
results compared to the ASM over the full spectral range.Comment: 6 pages, 5 figure
Mode-coupling theory for reaction dynamics in liquids
A theory for chemical reaction dynamics in condensed phase systems based on
the generalized Langevin formalism of Grote and Hynes is presented. A
microscopic approach to calculate the dynamic friction is developed within the
framework of a combination of kinetic and mode-coupling theories. The approach
provides a powerful analytic tool to study chemical reactions in realistic
condensed phase environments. The accuracy of the approach is tested for a
model isomerization reaction in a Lennard-Jones fluid. Good agreement is
obtained for the transmission coefficient at different solvent densities, in
comparison with numerical simulations based on the reactive-flux approach.Comment: 7 pages, 3 figure
Periodic negative differential conductance in a single metallic nano-cage
We report a bi-polar multiple periodic negative differential conductance
(NDC) effect on a single cage-shaped Ru nanoparticle measured using scanning
tunneling spectroscopy. This phenomenon is assigned to the unique
multiply-connected cage architecture providing two (or more) defined routes for
charge flow through the cage. This, in turn, promotes a self- gating effect,
where electron charging of one route affects charge transport along a
neighboring channel, yielding a series of periodic NDC peaks. This picture is
established and analyzed here by a theoretical model
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