LMP Seminar: Nonreciprocal collective dynamics in a mixture of phoretic Janus colloids
LMP Seminar
- Date: Apr 23, 2024
- Time: 02:00 PM - 03:30 PM (Local Time Germany)
- Speaker: Dr. Gennaro Tucci
- Dept. of Living Matter Physics, MPI for Dynamics and Self-Organization
- Location: Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS)
- Room: Riemannraum 1.40 & ZOOM Meeting ID: 997 1155 2453 Passcode: 771001
- Host: MPIDS / LMP
- Contact: golestanian-office@ds.mpg.de
A multicomponent mixture of Janus colloids with distinct catalytic coats and phoretic mobilities is a promising theoretical system to explore the collective behavior arising from nonreciprocal interactions. An active colloid produces (or consumes) chemicals, self-propels, drifts along chemical gradients, and rotates its intrinsic polarity to align with a gradient. As a result the connection from microscopics to continuum theories through coarse-graining couples densities and polarization fields in unique ways. Focusing on a binary mixture, we show that these couplings render the unpatterned reference state unstable to small perturbations through a variety of instabilities including oscillatory ones which arise on crossing an exceptional point or through a Hopf bifurcation. For fast relaxation of the polar fields, they can be eliminated in favor of the density fields to obtain a microscopic realization of the Nonreciprocal Cahn-Hilliard model for two conserved species with two distinct sources of non-reciprocity, one in the interaction coefficient and the other in the interfacial tension. Our work establishes Janus colloids as a versatile model for a bottom-up approach to both scalar and polar active mixtures.