RT Journal Article T1 Dynamical approach to the Casimir effect A1 Soto, R. A1 Brito López, Ricardo AB Casimir forces can appear between intrusions placed in different media driven by several fluctuation mechanisms, either in equilibrium or out of it. Herein, we develop a general formalism to obtain such forces from the dynamical equations of the fluctuating medium, the statistical properties of the driving noise, and the boundary conditions of the intrusions (which simulate the interaction between the intrusions and the medium). As a result, an explicit formula for the Casimir force over the intrusions is derived. This formalism contains the thermal Casimir effect as a particular limit and generalizes the study of the Casimir effect to such systems through their dynamical equations, with no appeal to their Hamiltonian, if any exists. In particular, we study the Casimir force between two infinite parallel plates with Dirichlet or Neumann boundary conditions, immersed in several media with finite correlation lengths (reaction-diffusion system, liquid crystals, and two coupled fields with non-Hermitian evolution equations). The driving Gaussian noises have vanishing or finite spatial or temporal correlation lengths; in the first case, equilibrium is reobtained and finite correlations produce nonequilibrium dynamics. The results obtained show that, generally, nonequilibrium dynamics leads to Casimir forces, whereas Casimir forces are obtained in equilibrium dynamics if the stress tensor is anisotropic. PB American Physical Society SN 1539-3755 YR 2011 FD 2011-03-02 LK https://hdl.handle.net/20.500.14352/43800 UL https://hdl.handle.net/20.500.14352/43800 LA eng NO © American Physical Society.This article has benefited from discussions with many colleagues: J. M. R. Parrondo, M. Clerc, N. van Kampen, O. Descalzi, F. Barra, A. Galindo, G. G. Alcaine, J. San Martin, and U. M. B. Marconi. P. R.-L. and R. B. are supported by the Spanish projects MOSAICO, UCM/PR34/07-15859, and MODELICO (Comunidad de Madrid). P. R.-L.'s research is also supported by a FPU MEC grant. The research is supported by Fondecyt Grants No. 1100100, No. 1070958, and No. 7070301, and Proyecto Anillo ACT 127. NO Spanish project MOSAICO NO Spanish project MODELICO (Comunidad de Madrid) NO FPU MEC NO Fondecyt NO Proyecto Anillo DS Docta Complutense RD 21 abr 2025