Mean Square Amplitude Of Fluctuations Research Articles

Statistical Analysis of Fluorescence Correlation Spectroscopy of Ultra Low Concentration Molecules with a Confocal Microscope

In this study, we simulated a statistical model of FCS(fluorescence correlation spectroscopy) based on a Poisson process to understand and explain observations of the experiment performed on molecules of ultra-low concentration by the home-built laser-scanning confocal microscope. The statistical model confirmed that the relative mean square amplitude of fluctuations is shown to be inversely proportional to the average number of molecules, even in the ultra-low concentration, if some conditions are satisfied. Signal-to-noise ratio and the variability of dwelling time under the confocal volume were found to be effective conditions for the experiment.

Hexatic Order and Liquid Density Fluctuations

We study the evolution of liquid structure factors with changing bond-orientational (hexatic) order. The form of the radial structure factor is found to depend strongly on the mean square amplitude of fluctuations in the hexatic order parameter. The effects of substrates on the hexatic ordering process in two dimensions are also examined. Our results apply not only to hexatic fluids, but also to other liquids whose local densities are coupled to $x\ensuremath{-}y$-like primary order parameters.

Superconducting fluctuations and the transmission line model

Abstract A recent calculation of the amplitude of charge-imbalance fluctuations in superconductors is shown to be consistent with the transmission line model of charge-imbalance dynamics due to Kadin et al. when thermal noise across the capacitance of the line is included in the model. This agreement justifies the calculation of the mean square amplitude of fluctuations of the local supercurrent by using the transmission line inductance. for a two-dimensional film, this results in an intrinsic pair-breaking rate which is proportional to the resistance per square of the film, R▭.