Regensburg 2016 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 16: Posters - Computational Biophysics
BP 16.4: Poster
Montag, 7. März 2016, 17:30–19:30, Poster C
Phase Transitions and Defects in a Flocking Model at High Density — •Felix Kempf1, Christoph A. Weber2, and Erwin Frey1 — 1Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, 80333 Munich, Germany — 2Department of Biological Physics, Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
To investigate active systems at high densities, we use computer simulations of a flocking model with repulsive interaction. Flocking models implement the core-features of active matter: self-propulsion and mutual alignment. At high densities, our model shows a transition reminiscent of melting in a 2d thermal crystal. Recently, the phase diagram was studied (C. Weber, C. Bock, and E. Frey, Phys. Rev. Lett. 112, 168301 (2014)), an open question was the role of defects in this transition. We now focus on the mutual interaction of dislocations in the crystaline phase. We explore phenomenology and statistics of the mutual interaction of two isolated dislocations in the ordered phase and compare the simulation results to a markovian model. The discrepancy between this simplified model and the statistics of the full simulations reveals that correlations are not negligible for defect interaction. We also observe a faster motion for short dislocation distances, which shows that the mechanisms governing the interactions in the near-range are fundamentally different compared to the far field.
In summary, our work elucidates phenomenology and statistics of the interaction of dislocation pairs in active high-density systems.