Generalized Casimir forces in nonequilibrium systems



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Brito, Ricardo and Soto, R. (2007) Generalized Casimir forces in nonequilibrium systems. Physical Review E, 76 (1, Par). ISSN 1539-3755

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In the present work, we propose a method to determine fluctuation-induced forces in nonequilibrium systems. These forces are the analog of the well-known Casimir forces, which were originally introduced in quantum field theory and later extended to the area of critical phenomena. The procedure starts from the observation that many nonequilibrium systems exhibit fluctuations with macroscopic correlation lengths, and the associated structure factors strongly depend on the wave vectors for long wavelengths; in some cases the correlations become long range, and the structure factors show algebraic divergences in the long-wavelength limit. The introduction of external bodies into such systems in general modifies the spectrum of these fluctuations, changing the value of the renormalized pressure, which becomes inhomogeneous. This inhomogeneous pressure leads to the appearance of a net force between the external bodies. It is shown that the force can be obtained from the knowledge of the structure factor of the homogeneous system. The mechanism is illustrated by means of a simple example: a reaction-diffusion equation, where the correlation function has a characteristic length. The role of this length in the Casimir force is elucidated.

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© American Physical Society. The authors thank J. M. Ortiz de Zárate for useful comments. R.B. acknowledges the hospitality of the Departamento de Física of Universidad de Chile. R.B. is supported by Secretaría de Estado de Educación y Universidades and the Projects MOSAICO, FIS2004-271, and UCM PR27/05-13923-BSCH. U.M.B.M. acknowledges COFIN-MIUR Grant No. 2005027808. R.S. acknowledges the hospitality of the Departamento de Física Aplicada I of Universidad Complutense de Madrid. R.S. is supported by Fondecyt research Grants No. 1030993 and No. 1061112 and Fondap Grant No.

Subjects:Sciences > Physics > Thermodynamics
ID Code:21325
Deposited On:17 May 2013 09:02
Last Modified:24 Jul 2018 11:01

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