LMP Seminar: Pattern formation in nonreciprocal quorum-sensing active particles

LMP Seminar

  • Datum: 21.11.2023
  • Uhrzeit: 14:00 - 15:30
  • Vortragende(r): Dr. Yu Duan
  • Department of Living Matter Physics, MPI-DS, Göttingen
  • Ort: Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS)
  • Raum: Riemannraum 1.40 & ZOOM Meeting ID: 997 1155 2453 Passcode: 771001
  • Gastgeber: MPIDS / LMP
  • Kontakt: golestanian-office@ds.mpg.de
Over the past years, the generation of interactions breaking action-reaction symmetry has emerged as new paradigm for active matter. Such nonreciprocal interactions have in particular been argued to constitute a generic route for the emergence of steady states breaking time reversal symmetry. The generalization of the Cahn-Hilliard theory of phase separation to nonreciprocal mixtures predicts, for example, the emergence of traveling states when intra-species attraction leads to demixing while chasing inter-species interactions are present. Here, we study a minimal model of active phase separation involving two species of particles regulating their self-propulsion speed via quorum-sensing rules. Combining simulations of the microscopic model and linear stability analysis of the associated coarse-grained field theory, we identify a mechanism for dynamical pattern formation that does not rely on the standard route of intra-species effective attractive interactions. Instead, our results reveal a highly dynamical phase of chasing bands induced only by the combined effects of self-propulsion and nonreciprocity in the inter-species couplings. Turning on self-attraction, we find that the system may phase separate into a macroscopic domain of such chaotic chasing bands coexisting with a dilute gas. We show that the chaotic dynamics of bands at the interfaces of this phase-separated phase results in anomalously slow coarsening.
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