title: Local exponents of nonlinear compression in periodically driven noisy oscillators.
abstract: Nonlinear compression of periodic signals is a key feature of the active amplifier in inner ear organs of all vertebrates. Different exponents alpha(0) in [-0.88,-0.5] of the sensitivity vs forcing amplitude |chi| approximately f(alpha(0)) have been observed. Here we calculate analytically the local exponent for a generic oscillator, the normal form of a Hopf bifurcation driven by noise and a periodic signal. For weak noise and sufficient distance from the bifurcation on the unstable side, the exponent may be close to -1 for moderate forcing amplitudes beyond linear response. Such strong compression is also found in a model of hair bundle motility.
authors.affiliation: Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lindner
authors.forename: Kai
authors.initials: K
authors.lastname: Dierkes
authors.forename: Frank
authors.initials: F
authors.lastname: Jülicher