Nature of self-diffusion in two-dimensional fluids

Autor: Peter Talkner, Akinori Kidera, Kyeong Hwan Han, Bongsik Choi, Changho Kim, Eok Kyun Lee
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: New Journal of Physics, vol 19, iss 12
Choi, B; Han, KH; Kim, C; Talkner, P; Kidera, A; & Lee, EK. (2017). Nature of self-diffusion in two-dimensional fluids. New Journal of Physics, 19(12). doi: 10.1088/1367-2630/aa997d. Lawrence Berkeley National Laboratory: Retrieved from: http://www.escholarship.org/uc/item/30c6c59k
DOI: 10.1088/1367-2630/aa997d.
Popis: Self-diffusion in a two-dimensional simple fluid is investigated by both analytical and numerical means. We investigate the anomalous aspects of self-diffusion in two-dimensional fluids with regards to the mean square displacement, the time-dependent diffusion coefficient, and the velocity autocorrelation function using a consistency equation relating these quantities. We numerically confirm the consistency equation by extensive molecular dynamics simulations for finite systems, corroborate earlier results indicating that the kinematic viscosity approaches a finite, non-vanishing value in the thermodynamic limit, and establish the finite size behavior of the diffusion coefficient. We obtain the exact solution of the consistency equation in the thermodynamic limit and use this solution to determine the large time asymptotics of the mean square displacement, the diffusion coefficient, and the velocity autocorrelation function. An asymptotic decay law of the velocity autocorrelation function resembles the previously known self-consistent form, $1/(t\sqrt{\ln t})$, however with a rescaled time.
Comment: 10 pages, to appear in New Journal of Physics
Databáze: OpenAIRE