Inspired by one-dimensional light-particle systems, the dynamics of a non-Hamiltonian system with long-range forces is investigated. While the molecular dynamics does not reach an equilibrium state, it may be approximated in the thermodynamic limit by a Vlasov equation that does possess stable stationary solutions. This implies that on a macroscopic scale the molecular dynamics evolves on a slow timescale that diverges with the system size. At the single-particle level, the evolution is driven by incoherent interaction between the particles, which may be effectively modeled by a noise, leading to a Brownian-like dynamics of the momentum. Because this self-generated diffusion process depends on the particle distribution, the associated Fokker-Planck equation is nonlinear, and a subdiffusive behavior of the momentum fluctuations emerges, in agreement with numerics.

Slow dynamics and subdiffusion in a non-Hamiltonian system with long-range forces / R. Bachelard, N. Piovella, S. Gupta. - In: PHYSICAL REVIEW. E. - ISSN 2470-0045. - 99:1(2019 Jan 18). [10.1103/PhysRevE.99.010104]

Slow dynamics and subdiffusion in a non-Hamiltonian system with long-range forces

N. Piovella;
2019-01-18

Abstract

Inspired by one-dimensional light-particle systems, the dynamics of a non-Hamiltonian system with long-range forces is investigated. While the molecular dynamics does not reach an equilibrium state, it may be approximated in the thermodynamic limit by a Vlasov equation that does possess stable stationary solutions. This implies that on a macroscopic scale the molecular dynamics evolves on a slow timescale that diverges with the system size. At the single-particle level, the evolution is driven by incoherent interaction between the particles, which may be effectively modeled by a noise, leading to a Brownian-like dynamics of the momentum. Because this self-generated diffusion process depends on the particle distribution, the associated Fokker-Planck equation is nonlinear, and a subdiffusive behavior of the momentum fluctuations emerges, in agreement with numerics.
Statistical and Nonlinear Physics; Statistics and Probability; Condensed Matter Physics
Settore FIS/03 - Fisica della Materia
Collective effects and optomechanics in ultra-cold matter
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/615123
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