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Nonlinear dynamics in a high‐gain amplifier: the dc SQUID
Author(s) -
Bulsara A.R.,
Wiesenfeld K.,
Inchiosa M.E.
Publication year - 2000
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/1521-3889(200010)9:9/10<679::aid-andp679>3.0.co;2-b
Subject(s) - squid , physics , nonlinear system , amplifier , oscillation (cell signaling) , quantum , interference (communication) , maxima and minima , condensed matter physics , quantum mechanics , optoelectronics , mathematical analysis , computer science , channel (broadcasting) , telecommunications , mathematics , ecology , genetics , cmos , biology
We study the detection of very weak time‐periodic magnetic signals via a double‐junction (dc) Superconducting Quantum Interference Device (SQUID). The device, represented by two coupled nonlinear differential equations for the quantum mechanical junction phase differences, admits long‐time static or oscillatory solutions, the transition between them being easily controlled by experimentally accessible parameters. Gain is maximal when the device is tuned to the onset of the oscillatory solutions; i.e., when the minima in the 2D potential function disappear. We concentrate on the SQUID dynamics near this critical point and compute the oscillation frequency via a center manifold reduction of the full 2D dynamics. Knowing this frequency permits its exploitation as a detection/classification tool in magnetic remote sensing applications.