Finite (box) size effects on transport properties
Dr. Benjamin Rotenberg (Laboratoire PHENIX, Sorbonne Université, Paris)

Simulations of fluids, regardless of the level of description, usually use periodic boundary conditions. This introduces biases in the computation of physical properties. For example, the diffusion coefficient depends on the size of the simulation box. Yeh and Hummer demonstrated the hydrodynamic origin of this effect and obtained an analytical expression to correct for this bias in the case of cubic boxes [1]. In this talk, I will review the main results of this pioneering study as well as some consequences and extensions on which we have worked in the recent years. After analyzing this effect for various water models [2], we showed the influence of the box shape, in addition to its size [3] before turning to the case of confined fluids [4]. Finally, we analyzed finite size effects on the transient regime using Lattice Boltzmann simulations [5]. In all cases, the hydrodynamic origin allows us to evaluate the correction to be applied to simulations (molecular as well as mesoscopic). I will also mention recent work from other groups on membrane dynamics as well as rotational dynamics.

[1] Yeh et Hummer, J. Phys. Chem. B 108 15873 (2004).

[2] Tazi et al, J. Phys. Cond. Matt., 24, 284117 (2012).

[3] Botan et al, Mol. Phys., 113, 2674 (2015).

[4] Simonnin et al, J. Chem. Theory Comput., 13, 2881 (2017).

[5] Asta et al, Phys. Rev. E, 95, 061301 (2017).