We use Langevin dynamics (LD) simulations to investigate single-file diffusion (SFD) in a dilute solution of flexible linear polymers inside a narrow tube with periodic boundary conditions (a torus). The transition from SFD, where the time ($t$) dependence of the mean-square displacement scales like $\langle x^2\rangle \sim t^{\frac{1}{2}}$, to normal diffusion with $\langle x^2\rangle \sim t$, is studied as a function of the system parameters, such as the size and concentration of the polymer chains and the width of the tube. We propose a phase diagram describing different diffusion regimes. In particular, we highlight the fact that there are two different pathways to normal long-time diffusion. We also map this problem onto a one-dimensional lattice Monte Carlo model where the diffusing object represents the polymer's center of mass. Possible extensions of this work to polydisperse polymer solutions, one-dimensional electrophoresis, and DNA mapping are discussed.

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• Confinement
• Diffusion
• Polymers