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arXiv · 0709.1465

Fluctuations and Rheology in Active Bacterial Suspensions

D. T. N. Chen·A. W. C. Lau·L. A. Hough·M. F. Islam·M. Goulian·T. C. Lubensky·A. G. Yodh
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Abstract

We probe non-equilibrium properties of an active bacterial bath through measurements of correlations of passive tracer particles and the response function of a driven, optically trapped tracer. These measurements demonstrate violation of the fluctuation-dissipation theorem and enable us to extract the power spectrum of the active stress fluctuations. In some cases, we observe $1/\sqrtω$ scaling in the noise spectrum which we show can be derived from a theoretical model incorporating coupled stress, orientation, and concentration fluctuations of the bacteria.

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D. T. N. Chen, A. W. C. Lau, L. A. Hough, M. F. Islam, M. Goulian, T. C. Lubensky, A. G. Yodh. 2007-09-10. Fluctuations and Rheology in Active Bacterial Suspensions. https://doi.org/10.1103/physrevlett.99.148302

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