The Anomalous Transport of Tracers in Active Baths

Omer Granek (Technion Haifa)

Sep 22. 2022, 10:00 — 11:00

We derive the long-time dynamics of a tracer immersed in a one-dimensional active bath. In contrast to previous studies, we find that the damping and noise correlations possess long-time tails with exponents that depend on the tracer symmetry. For generic tracers, shape asymmetry induces ratchet effects that alter fluctuations and lead to superdiffusion and friction that grows with time when the tracer is dragged at a constant speed. In the singular limit of a completely symmetric tracer, we recover normal diffusion and finite friction. Furthermore, for small symmetric tracers, the active contribution to the friction becomes negative: active particles enhance motion rather than oppose it. These results show that, in low-dimensional systems, the motion of a passive tracer in an active bath cannot be modeled as a persistent random walker with a finite correlation time.

Further Information
Venue:
ESI Schrödinger and Boltzmann Lecture Hall
Recordings:
Recording
Associated Event:
Large Deviations, Extremes and Anomalous Transport in Non-equilibrium Systems (Thematic Programme)
Organizer(s):
Christoph Dellago (U of Vienna)
Satya Majumdar (U Paris Sud, Orsay)
David Mukamel (Weizmann Institute, Rehovot)
Harald Posch (U of Vienna)
Gregory Schehr (U Paris Sud, Orsay)