2026/08/06 by Patrick Jentsch, Anna Erzberger
Physics and Astronomy · #cond-mat.soft
6 pages, 1 figure, 13 pages of supplemental material
arxiv created 2026/08/06 · arxiv updated 2026/08/07
Living matter undergoes continuous turnover. The hydrodynamic theory of Malthusian flocks describes polar active matter with turnover, but its phase diagram and nonlinear scaling behavior is not well understood. Using a nonperturbative renormalization group approach, rotationally invariant to second order in derivatives, and without defects, we explicitly obtain the strong-coupling fixed point governing true long-range order, uncover a quasi long-range ordered phase, and identify a critical point similar to, but distinct from the Berezinskii-Kosterlitz-Thouless universality class at the transition.