Zigzag transitions and nonequilibrium pattern formation in colloidal chains

摘要: Paramagnetic colloidal particles that are optically trapped in a linear array can form zigzag pattern when an external magnetic field induces repulsive interparticle interactions. When the traps abruptly turned off, nonequilibrium expanding with symmetry, even strength of interaction is weaker than required to break symmetry equilibrium state. We show transition state always potentially possible for purely harmonic traps. For anharmonic have finite height, becomes unstable above critical anharmonicity. A normal mode analysis line configuration demonstrates increasing leads hardening and softening spring constants longitudinal transverse directions, respectively. The first which explains patterns. Our analytically tractable models help give further insight into way interplay such factors as length chain, hydrodynamic interactions, thermal fluctuations affect formation evolution experimentally observed