title: Effective diffusion coefficient of a Brownian particle in a periodically expanded conical tube.
abstract: Diffusion in a tube of periodically varying diameter occurs slower than that in a cylindrical tube because diffusing particles get trapped in wells of the periodic entropy potential which is due to variation of the tube cross-section area. To quantify the slowdown one has to establish a relation between the effective diffusion coefficient of the particle and the tube geometry, which is a very complicated problem. Here we show how to overcome the difficulties in the case of a periodically expanded conical tube, where we find an approximate solution for the effective diffusion coefficient as a function of the parameters determining the tube geometry.
authors: Moscow State University, Faculty of Fundamental Physical and Chemical Engineering, GSP-1, 1-51 Leninskie Gory, Moscow 119991, Russia.
authors: Anatoly E
authors: AE
authors: Antipov
authors: The Royal Bank of Scotland, 250 Bishopsgate, London EC2M 4AA, United Kingdom.
authors: Alexander V
authors: AV
authors: Barzykin
authors: Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors: Alexander M
authors: AM
authors: Berezhkovskii
authors: Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Prospect 29, Moscow 19991, Russia.
authors: Yurii A
authors: YA
authors: Makhnovskii
authors: Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13, Bldg. 2, Moscow 125412, Russia.
authors: Vladimir Yu
authors: VY
authors: Zitserman
authors: Institute of Problems of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia.
authors: Sergei M
authors: SM
authors: Aldoshin