Chaos, noise, and tails on the I-V curve steps of RF-driven Josephson junctions

Journal Article · Thu Feb 28 23:00:00 EST 1985 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.31.2667· OSTI ID:5932545

Cronemeyer, D C; Chi, C C; Davidson, A; Pedersen, N F

We report the first experiments and digital and analog simulations which demonstrate the existence of chaotic regions in the I-V curves of dc- and RF-current-biased Josephson junctions. These junctions were formed of crossed Pb strips and were shunted with Au resistors. Chaos appears as negatively going tails on the trailing edges of the RF-induced steps; these tails, which may be as large as 50% of the voltage step width, have not previously been reported. The parameters for the occurrence of these tails center at ..beta../sub c/ = 4, ..cap omega.. = ..omega../..omega../sub p/ = 0.15, i/sub RF/ = I/sub RF//I/sub c/ = 1.04, I/sub c/ = 3 x 10/sup 5/ A/m/sup 2/ at 4.2 K. The thermal noise of the shunting resistor was emulated by a Gaussian spectrum. The presence of such noise dramatically alters the substeps, spikes, and bifurcations predicted for zero temperature. With only small amounts of noise, such complexities disappear, and are replaced by a smooth tail on the step accompanied by broadband noise. There is good agreement between the experiments on a real junction, simulations with a phase-locked loop, and numerical calculations with a digital computer.

• Research Organization: IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598
• OSTI ID: 5932545
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 31:5; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALTERNATING CURRENT
CRITICAL CURRENT
CURRENTS
DIRECT CURRENT
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
JOSEPHSON JUNCTIONS
JUNCTIONS
MATHEMATICS
NOISE
NUMERICAL ANALYSIS
PHYSICAL PROPERTIES
RF SYSTEMS
SIMULATION
SUPERCONDUCTING JUNCTIONS