Condensed Matter Seminar - Oleh Turutanov (28.5.2026)
Thursday 14.5.2026 at 14:00, Lecture room F1 108
Oleh Turutanov, PhD.:
Stochastic Resonance in SQUIDs and everywhere
Abstract:
It seems obvious that random noise always interferes with seeing, hearing, and measuring a weak information signal, and is the complete opposite of regularity and order. However, the discovery in 1981 of a completely counterintuitive phenomenon, the stochastic resonance (SR) effect, completely changed the attitude toward noise as an interference.
It turned out that in a wide class of nonlinear systems, both natural and artificial, adding an optimal amount of noise increases their response to a weak regular stimulus, i.e., leads to ordering and amplification of the weak signal. This opens the possibility of increasing the sensitivity of various technical devices when measuring weak periodic signals against a noisy background. One such device is the superconducting quantum interferometer (SQUID), which is widely used in various fields—laboratories, medicine, geophysics, industry, and the military—as a sensitive sensor of weak magnetic fields. The report presents the essence of stochastic resonance and its manifestation in nature and technology using the example of bistable and threshold systems, as well as the results of numerical calculations and experiments on observing SR in an RF SQUID at liquid helium temperature, which under certain conditions have two or more metastable states.