Figure 1

(Color online) (a) Asymmetric particle tumbling in a periodically segmented 2D channel. The pores, $2\Delta$ wide, are centered on the channel axis. (b) Elliptic particle with semiaxes $a$ and $b$, at rest against a compartment wall. Note that $a<\Delta <b$. (c) Elliptic particle in escape position, its major axis forming a maximum angle ${\varphi }^{\ast }$ with the channel axis.Reuse & Permissions

Figure 2

(Color online) ANM for a driven-pulsated elongated Brownian particle: current $⟨v⟩$ vs static bias $F_0$ in the presence of square-wave drives with amplitude $F_1=2$ and different periods $T_{\Omega }$ (see legend). Other simulation parameters: Diffusion strengths $D=D_r=D_{\varphi }=0.1$; shape parameters $a=0.05$, $b=0.3$; compartment parameters $x_L=y_L=1$, and $\Delta =0.1$. Each data point for $⟨v⟩\equiv {\text{lim}}_{t\to \infty }⟨x\left(t\right)-x\left(0\right)⟩/t$ was computed from a single trajectory with $t={10}^6$ and time-step ${10}^{-5}$; the statistical error was estimated to be 5%, i.e., of the order of the symbol size. Note, for a comparison, that the compartment traversal time is ${\tau }_0=7$ and the diffusive relaxation times are ${\tau }_D^{\left(x\right)}={\tau }_D^{\left(y\right)}=5$. The dotted curve represents $v\left(F\right)$ at zero ac-drive, $F_1=0$. Inset: the corresponding mobility curve (solid curve), $\mu \left(F\right)$, is compared with the analytical estimate of Eq. (4) (dashed curve) for $F_m=0.86$.Reuse & Permissions

Figure 3

(Color online) (a) Drive waveform dependence: $⟨v⟩$ vs $F_0$ for three waveforms of $F_{ac}\left(t\right)$, square (as in Fig. 2), sinusoidal and ramped, all with $F_1=2$, $D=0.02$, and $T_{\Omega }={10}^3$. (b) Particle inertia dependence: $⟨v⟩$ vs $F_0$ for three values of $m=I$, see text. Other simulation parameters are $F_1=2$, $D=0.1$, and $T_{\Omega }=500$.Reuse & Permissions

Figure 4

(Color online) Particle elongation dependence: $⟨v⟩$ vs $b$ for different values of $T_{\Omega }$ (main panel) and of $D$ (inset). Other simulation parameters: square-wave ac-drive with amplitude strength $F_1=2$, and bias $F_0=1$, $a=0.05$, $x_L=y_L=1$, and $\Delta =0.1$.Reuse & Permissions

Figure 5

(Color online) Rotational translational diffusion dependence: $⟨v⟩$ vs $D_{\varphi }/D_r$ for different values of $D_r$ (see legend). Inset: $⟨v⟩$ vs $D=D_r=D_{\varphi }$ with $D_{\varphi }/D_r=1$. The arrows mark the asymptotes predicted in the text. Other simulation parameters are as in Fig. 4 with $b=0.3$.Reuse & Permissions