Optimal Transport of an Anisotropic Tracer in Dense Active Suspensions

@misc{tiwari2026optimal,
  title = {{Optimal Transport of an Anisotropic Tracer in Dense Active Suspensions}},
  author = {Chandranshu Tiwari and Sunil P. Singh},
  howpublished = {arXiv},
  year = {2026},
  month = aug,
  doi = {10.48550/arxiv.2608.30377},
  eprint = {2608.30377},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.30377},
}

TY  - UNPB
TI  - Optimal Transport of an Anisotropic Tracer in Dense Active Suspensions
AU  - Chandranshu Tiwari
AU  - Sunil P. Singh
PY  - 2026
DA  - 2026/08/31
PB  - arXiv
DO  - 10.48550/arxiv.2608.30377
UR  - https://arxiv.org/abs/2608.30377
AB  - The transport of anisotropic tracers in active fluids exhibits rich dynamical behavior arising from the interplay between particle shape, activity, and steric interactions. We employ Brownian dynamics simulations to investigate the motion of an elliptical tracer immersed in a suspension of active dumbbells. We find that both translational and rotational transport, characterized by the mean-square speed and diffusivity, are enhanced by more than an order of magnitude with increasing area fraction, ϕ, of active dumbbells. Notably, tracer motion is enhanced along the major axis relative to the minor axis, with v_∥>v_⊥ and D_∥>D_⊥. Remarkably, both translational and rotational transport exhibit an optimum at an intermediate packing fraction of active dumbbells, with the corresponding transport coefficients decreasing at higher densities. We show that this non-monotonic transport arises from the anisotropic accumulation and aggregation of active dumbbells around the tracer, which control the non-equilibrium force and torque fluctuations. Thus, establish a direct connection between the collective organization of active dumbbells at the tracer surface and its emergent translational and rotational transport.
ER  -