Effects of error on fluctuations under feedback control.

Department of Physics, The University of Tokyo-Hongo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan.
Physical Review E (Impact Factor: 2.33). 08/2011; 84(2 Pt 1):021123. DOI: 10.1103/PhysRevE.84.021123
Source: PubMed

ABSTRACT We consider a one-dimensional brownian motion under nonequilibrium feedback control. Generally, the fluctuation-dissipation theorem (FDT) is violated in driven systems under nonequilibrium conditions. We find that the degree of the FDT violation is bounded by the mutual information obtained by the feedback system when the feedback protocol includes measurement errors. We introduce two simple models to illustrate cooling processes by feedback control and demonstrate analytical results for the cooling limit in those systems. Especially in a steady state, lower bounds to the effective temperature are given by an inequality similar to the Carnot efficiency.

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