Fig. 4: Stability of the axial swimming state.
From: A transition to stable one-dimensional swimming enhances E. coli motility through narrow channels
a Effective potential for the cell center along the transverse coordinate in the five smallest tunnels. The potential is computed as the logarithm of the cell position probability distributions shown in Fig. 2c and shows a minimum where axial swimming is stable. Each solid line plots the best quadratic fit to experimental data. b Comparison between the curvatures of the fitted effective potential κ (white squares) and the restoring speed gradient α (see Eq. (1)) obtained from numerical simulations. Orange squares and blue circles plot simulations results for tunnels with square and circular section respectively.
