For a simple example of on-off intermittency, an overdamped Kramers oscillator with multiplicative noise, we demonstrate a phenomenon of hypersensitivity to ultrasmall time-dependent signals.[S0031-9007(98)06229-2] PACS numbers: 05.40.+j, 05.45.+b
In a simple system with periodic symmetric potential, the phase model under
effect of strong multiplicative noise or periodic square wave, we found a giant
response, in the form of directed flux, to an ultrasmall dc signal. The
resulting flux demonstrates a bell-shaped dependence on multiplicative noise
correlation time and occurs even in the case of large (compared to the signal)
additive noise.Comment: 3 EPS figures, submitted to Phys.Lett.
We have performed detailed measurements of two components, and , of the electric field vector in high- superconducting (HTS) ceramics, , as functions of the transport current along the z-axis and of the angle between a constant external magnetic field applied in the sample plane and the current direction. Note that we are aware of no other publications concerned with measurements. It was found that depends on only slightly, varying by , and is of the order of 0.1. Two types of dependence are possible in the low-field electrodynamics. In this domain the HTS ceramic is a Josephson medium, with the penetration of magnetic field into it governed by the parameter where a is the grain size, is the flux quantum and is the critical current density. If , then the effective penetration depth , and the conventional flux-line-cutting model, characterized by a parametrically large anisotropy of and , is valid. If , then the effective medium theory is inapplicable, and the current - voltage characteristics (CVCs), related to the penetration of magnetic field quanta through single Josephson junctions, are determined by the nonlinear properties of these junctions, which are independent of the angle . It is this fact that leads to an isotropic CVC. Our results indicate that the second situation is realized.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.