Bistable Noise Research Articles

Modeling Active Non-Markovian Oscillations.

Modeling noisy oscillations of active systems is one of the current challenges in physics and biology. Because the physical mechanisms of such processes are often difficult to identify, we propose a linear stochastic model driven by a non-Markovian bistable noise that is capable of generating self-sustained periodic oscillation. We derive analytical predictions for most relevant dynamical and thermodynamic properties of the model. This minimal model turns out to describe accurately bistablelike oscillatory motion of hair bundles in bullfrog sacculus, extracted from experimental data. Based on and in agreement with these data, we estimate the power required to sustain such active oscillations to be of the order of 100 k_{B}T per oscillation cycle.

Analysis of bistable noise from microfabricated field emission cathodes

Field emission current fluctuations from microfabricated cathodes have been investigated. Time-correlated noise measurements and field emission electron microscope images indicate that the dominant current fluctuations are bistable in character and are emitted from a few localized sites on the cathode surface. Apertured bistable current transitions from these emission sites are often significantly larger than the percent change in total emitted current. Analysis of bistable pulse lengths has shown that the dwell time in a particular bistable emission state decays exponentially with time. Current autocorrelation measurements indicate that bistable noise at ⩽300 K is generated by adsorbates switching between emission states and not by adsorbate diffusion.

Evidence that burst noise is a multi-step phenomenon

A detailed study of the rise and fall transients of burst noise in forward biassed P- N junctions has revealed that even “simple” bistable noise transitions can be a succession of randomly delayed small steps. Other more complicated waveforms have also been resolved into a succession of weakly correlated pulses. When subjected to frequency limited amplification such trains of pulses tend to merge such that the observed output waveforms give the appearance of having long and unusually shaped rise and fall transients. The multi-step phenomena described in this paper may in fact be indicative of a type of behaviour which is a general feature of defect systems in electronic microstructures.

Low-frequency noise in silicon-gate metal-oxide-silicon capacitors before oxide breakdown

Measurements of the fluctuations in the tunneling current It through a thin SiO2 insulating layer, by means of an ultralow noise measurement set, showed that after a first time interval in which its power spectral density is stationary and proportional to I2t, an on-off modulation of It arises, just before oxide breakdown. This bistable noise seems to be related to localized phenomena controlled by trapping-detrapping processes within the oxide. Two possible mechanisms which could give rise to this bistable noise are discussed.

Bistable noise in operational amplifiers

Bistable noise in operational amplifiers has been investigated. Equivalent circuits are used. It is shown that by changing the source resistance of an operational amplifier the locations of bistable noise sources can be determinated. Both burst noise and microplasma noise observed from an operational amplifier. The input transistors of an operational amplifier are the most important bistable noise sources. Burst noise due to elements other than the input transistors is shown to be important. Surface effects on burst noise have been discussed. Because of the surface effect, n-p-n transistors are expected to show more burst noise than p-n-p transistors. Microplasma noise in an operational amplifier is attributed to a local surface breakdown.

Bistable noise in p- n junctions

Two types of bistable noise, burst noise and microplasma noise, have been investigated with particular emphasis on that under reverse-bias operations. The physical models for them are reviewed and generalized, and the distinction between burst noise and microplasma noise is discussed. The experimental results indicate that the mechanism responsible for burst noise in a reverse-biased p- n junction is the same as that in a forward-biased p- n junction. It is also shown that the fluctuation amplitude of the effective potential barrier can be determined by the measurements of the amplitude of burst noise pulses as functions of temperature.