Boundary layers, transport and universal distribution in boundary driven active systems
Pritha Dolai, Arghya Das
SciPost Phys. 19, 088 (2025) · published 8 October 2025
- doi: 10.21468/SciPostPhys.19.4.088
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Abstract
We discuss analytical results for a run-and-tumble particle (RTP) in one dimension in presence of boundary reservoirs. It exhibits "kinetic boundary layers", nonmonotonous distribution, current without density gradient, diffusion facilitated current reversal and optimisation on tuning dynamical parameters, and a new transport effect in the steady state. The spatial and internal degrees of freedom together possess a symmetry, using which we find the eigenspectrum for large systems. The eigenvalues are arranged in two bands which can mix in certain conditions resulting in a crossover in the relaxation. The late time distribution for large systems is obtained analytically; it retains a strong and often dominant "active" contribution in the bulk rendering an effective passive-like description inadequate. A nontrivial "Milne length" also emerges in the dynamics. Finally, a novel universality is proposed in the absorbing boundary problem for dynamics with short-range colored noise. Active processes driven by active reservoirs may thus provide a common physical ground for diverse and new nonequilibrium phenomena.
Authors / Affiliations: mappings to Contributors and Organizations
See all Organizations.- 1 2 3 Pritha Dolai,
- 4 Arghya Das
- 1 Friedrich-Alexander-Universität Erlangen-Nürnberg / University of Erlangen-Nuremberg [FAU]
- 2 राष्ट्रीय प्रौद्योगिकी संस्थान / National Institute of Technology Karnataka [NITK]
- 3 Max-Planck-Zentrum für Physik und Medizin / Max Planck Institute for Physics and Medicine [MPZPM]
- 4 கணித அறிவியல் கழகம் / Institute of Mathematical Sciences [IMSc]
