Speed up of passive tracers in mixtures with active chemical reactions
Abstract
Diffusivity of passive tracers in complex mixtures is widely relevant for industrial applications and for probing biological systems. Interactions with the surrounding medium typically generate a drag force that suppresses tracer diffusion, although self-propulsion can accelerate tracers via active fluctuations. Similar effects are not understood in mixtures with particle conversion and exchange, although these are particularly relevant in biological contexts, where actively driven reactions prevail. By studying a thermodynamically consistent model of chemical reactions in mixtures, we show that reactions provide an additional relaxation pathway that suppresses interaction-induced memory, reducing the drag on tracers and restoring their diffusivity toward the value expected in the absence of solutes. Moreover, active reactions generate nonequilibrium fluctuations that can push tracer diffusivity beyond this limit, an effect we confirm with particle-based simulations. Our results identify chemical activity as a distinct route to controlling mass transport and offer a framework for interpreting microrheology experiments in chemically active mixtures.
Related
- Persistence-driven void formation in dense active-passive mixtures
- Aggressive Phase Separation in Dense Mixtures of Passive and Active Particles
- Spatial and Temporal Control of Avalanches in Dense Active-Passive Mixtures
- Density Accelerated Relaxation in Active Passive Colloidal Networks with Competing Interactions
- Chemical potentials from structure factors: II. Charged multi-component mixtures
BibTeX
@misc{thewes2026speed,
title = {{Speed up of passive tracers in mixtures with active chemical reactions}},
author = {Filipe C. Thewes and Chengjie Luo and David Zwicker},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.29416},
eprint = {2609.29416},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.29416},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Speed up of passive tracers in mixtures with active chemical reactions
AU - Filipe C. Thewes
AU - Chengjie Luo
AU - David Zwicker
PY - 2026
DA - 2026/09/24
PB - arXiv
DO - 10.48550/arxiv.2609.29416
UR - https://arxiv.org/abs/2609.29416
AB - Diffusivity of passive tracers in complex mixtures is widely relevant for industrial applications and for probing biological systems. Interactions with the surrounding medium typically generate a drag force that suppresses tracer diffusion, although self-propulsion can accelerate tracers via active fluctuations. Similar effects are not understood in mixtures with particle conversion and exchange, although these are particularly relevant in biological contexts, where actively driven reactions prevail. By studying a thermodynamically consistent model of chemical reactions in mixtures, we show that reactions provide an additional relaxation pathway that suppresses interaction-induced memory, reducing the drag on tracers and restoring their diffusivity toward the value expected in the absence of solutes. Moreover, active reactions generate nonequilibrium fluctuations that can push tracer diffusivity beyond this limit, an effect we confirm with particle-based simulations. Our results identify chemical activity as a distinct route to controlling mass transport and offer a framework for interpreting microrheology experiments in chemically active mixtures.
ER -