LMP Seminar: Extreme spontaneous deformations of active crystals

LMP Seminar

  • Datum: 20.02.2024
  • Uhrzeit: 15:00 - 16:30
  • Vortragende(r): Prof. Xiaqing Shi
  • Center for soft condensed matter physics and interdisciplinary research, Soochow university, China
  • 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
We demonstrate that two-dimensional crystals made of active particles can experience extremely large spontaneous deformations without melting [1]. Using particles mostly interacting via pairwise repulsive forces, we show that such active crystals maintain long-range bond order and algebraically decaying positional order, but with a decay exponent whose value is not limited by the 1/3 bound given by the (equilibrium) KTHNY theory.
We rationalize our findings using linear elastic theory and show the existence of two well-defined effective temperatures quantifying respectively large-scale deformations and bond-order fluctuations. We argue that the root of these phenomena lies in the sole time-persistence of the effective noise felt by particles. They should thus be observed in many different situations, a few of which we discuss.

[1] Shi, X., Cheng, F. & Chaté, H. Phys. Rev. Lett. 131, 108301 (2023)
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