Active Colloids in Harmonic Optical Potentials

Abstract

We study the motion of active patchy colloids in an optical trap using experiments, theory and numerical simulations. To achieve isotropic and harmonic confinement, we prototype microparticles with a nearly uniform refractive index and verify that, in the absence of activity, the confined motion is identical to that of optically homogeneous Brownian particles. If the activity is turned on by means of vertical AC fields, the density distributions are described by Boltzmann-like statistics (Gaussian with effective temperature) only for strongly confining traps, whereas weaker potentials give rise to non-Gaussian distributions with a bimodal shape. Our results showcase a simple way to study active soft matter in optical potential landscapes eliminating the optical torque.

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Cited by in corpus (16)

• Chiral active matter in external potentials
• Nonequilibrium steady state of trapped active particles
• Confined run and tumble particles with non-Markovian tumbling statistics
• Statistical mechanics of passive Brownian particles in a fluctuating harmonic trap
• Activity-assisted barrier-crossing of self-propelled colloids over parallel microgrooves
• Nonequilibrium steady state of Brownian motion in an intermittent potential
• Emergent short-range repulsion for attractively coupled active particles
• Active-matter isomorphs in the size-polydisperse Ornstein-Uhlenbeck Lennard-Jones model
• Emergence of oscillatory states of self-propelled colloids under optical confinement
• Island Hopping of active colloids
• Inverted Sedimentation of Active Particles in Unbiased ac Fields
• Dynamically stable optical trapping of thermophoretically active Janus colloids
• Curvature dependent dynamics of a bacterium confined in a giant unilamellar vesicle
• Crystal to liquid cross-over for active particles with inverse-square power-law interaction
• From Attraction to Repulsion: Emergent Interactions in Harmonically Coupled Active Binary System
• Active adaptolates: motility-induced percolating structures with an adaptive packing geometry