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Stochastic resonance in nanoscale systems

Posted on:2012-04-10Degree:Ph.DType:Thesis
University:University of Alberta (Canada)Candidate:Saha, Aditya AFull Text:PDF
GTID:2450390011455507Subject:Physics
Abstract/Summary:
This thesis considers the possibility of stochastic resonance (SR) in the following nanoscale systems: (i) hard-threshold devices; (ii) averaging structures of carbon nanotubes (CNTs); (iii) myoglobin atoms; and finally (iv) tubulin dimers. The description of SR is carried out using Kramers' rate theory in the adiabatic two-state approximation for continuous systems and using Shannon's information theoretic formalism for systems with static nonlinearities. The effective potentials are modelled by asymmetric or symmetric bistable wells in a single reaction co-ordinate. Quantum considerations have not been invoked. Hence, all results are implicitly valid in the high-temperature regime of relevance to industrial applications. It is established that information transmitted by arrays of identical CNTs is maximized by non-zero noise intensities and that the response of myoglobin and tubulin dimers to ambient molecular forces (as described by the signal-to-noise ratio or SNR) is enhanced by increasing temperature. Sample calculations are shown for solvent fluctuations, ligand interactions and dipole oscillations. These results can be used to explain: (i) the effects of temperature observed in fabrication processes for CNTs; (ii) the dynamical transition observed in myoglobin and (iii) the 8.085 MHz resonance observed in microtubules.
Keywords/Search Tags:Resonance, Systems
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