Dynamics of a Brownian circle swimmer

Abstract

Self-propelled particles move along circles rather than along a straight line when their driving force does not coincide with their propagation direction. Examples include confined bacteria and spermatozoa, catalytically driven nanorods, active, anisotropic colloidal particles and vibrated granulates. Using a non-Hamiltonian rate theory and computer simulations, we study the motion of a Brownian "circle swimmer" in a confining channel. A sliding mode close to the wall leads to a huge acceleration as compared to the bulk motion, which can further be enhanced by an optimal effective torque-to-force ratio.

Diffusive behaviors of circle-swimming motors

“…3 we show the SDs of three individual motors at H 2 O 2 concentrations of 0.135%, 0.253%, and 0.5%. The circle swimmers' SDs exhibit different behavior in short-and long-time scales [10,34,37]. For t < π/ω the SD increases from zero to a local maximum of approximately v 2 /ω 2 .…”

“…The simulations are carried out with the modified Langevin equations for two dimensions shown in Equations (2)- (4) and assume that the standard twodimensinoal (2D) Langevin equations are modified such that the displacement of the motors is the sum of its advective and Brownian components [10,34]. The advective velocity of the motors is only in the direction of orientation of the motors and the orientation is governed by a sum of the Brownian and time averaged rotational velocity.…”

“…By calculating the MSD of the motors they were able to determine the effective diffusivity of the motors as a function of concentration and show that for rotationally diffusive swimmers the long-time effective diffusivity is [9] [10,34],…”

“…The Brownian fluctuations terms, ξ and ζ , are Gaussian random variables with zero mean and whose magnitudes are determined from theoretical isotropic Brownian diffusivities. In Ebbens et al [10] and van Teeffelen and Löwen [34] Eqs. (2)- (4) are solved to determine the MSD,…”

Getting drowned in a swirl: Deformable bead-spring model microswimmers in external flow fields

“…[1][2][3][4][5][6] for recent reviews. This includes the individual dynamics of particles with complex shape [7][8][9], as well as cases of self-rotation [9][10][11][12][13][14][15]. Furthermore, the collective behavior of many such interacting particles has been explored [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35].…”