Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 21: Neurobiophysics and Sensory Transduction

BP 21.4: Vortrag

Mittwoch, 24. März 2010, 15:00–15:15, H43

Local exponents of nonlinear compression in periodically driven noisy oscillators — •Benjamin Lindner, Kai Dierkes, and Frank Jülicher — Max-Planck-Institut für Physik komplexer Systeme, Dresden, Germany

Nonlinear compression of periodic signals is a key feature of the active amplifier in inner ear organs of all vertebrates. Different exponents α₀∈ [−0.88,−0.5] of the sensitivity vs forcing amplitude |χ|∼ f^α₀ 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. Ref.: Lindner, Dierkes, Jülicher Phys. Rev. Lett. (in print, 2010)