On the anomalous flicker noise intensity in high-temperature superconductors

Abstract

The problem of anomalously high levels of flicker noise observed in the normal state of the hightemperature superconductors is addressed. It is argued that the anomaly is the result of incorrect normalization of the power spectra according to the Hooge formula. A careful analysis of the available experimental data is given, which shows that the scaling of the spectral power with sample size is essentially different from the inverse proportionality. It is demonstrated that the measured spectra obey the law given by the recently proposed quantum theory of fundamental flicker noise.

Electric field activated nonlinear 1/ffluctuations in Fe(Te, Se) superconductors

“…A model that predicts a temperature dependence of α H is the quantum theory of fundamental flicker noise. This theory attributes the measured noise to finite-temperature quantum electromagnetic fluctuations produced by elementary charge carriers in external electric field [34]. In this case, the noise level can be expressed in terms of α H as…”

Quantum theory of flicker noise: the 1/f law as a lower bound on the voltage power spectrum

“…To be sure, this does not exclude the possibility that the noise level might be lower, but is raised to the observed level by an independent measurable effect. In fact, the photon heat bath contribution to the 1/f noise in high-temperature superconductors at room temperature is of the same order as the vacuum contribution [28].…”

“…Evidently, these terms represent the product Û (t) Û (t ′ ) , and so their sum just cancels the last term in Eq. (28), provided that all charges present in the system, localised as well as mobile, are taken into account in the shaded blob in Fig. 1(a).…”

“…This issue was considered in detail in Ref. [28] where it was demonstrated that the anomaly in the noise level is spurious; it is caused by an inappropriate normalization of the power spectra using Hooge's formula [29] according to which S(f ) ∼ 1/Ω, whereas actually S(f ) is inversely proportional to the linear sample size. Here we will only show on a couple of examples that the "huge" noise is in fact not far from the minimum given by Eq.…”

noise in spectral fluctuations of complex networks

“…The ''1/f -like'' noise is the general name of an oscillation whose power spectrum is in inverse proportion to the frequency. It has been observed in various phenomena such as electrical circles, car flow on a highway, the variance of temperature with seasons, music, pulses of people, DNA sequences etc [7,8]. Although considerable research has been done in the direction of network spectra, whether 1/f α -noise arising in the spectra of complex networks or not is still an open question.…”