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Absolute Negative Mobility of an Active Tracer in a Crowded Environment
Pierre Rizkallah1, Alessandro Sarracino2,3, Olivier Bénichou4
1Sorbonne Université, CNRS, Laboratoire de Physico-Chimie des Électrolytes et Nanosystèmes Interfaciaux (PHENIX), 4 Place Jussieu, 75005 Paris, France.
Physical Review Letters
|June 9, 2023
Summary
Absolute negative mobility (ANM) occurs when a driven tracer moves against the applied force. This study provides a microscopic theory, showing ANM emerges from an active tracer interacting with mobile crowders on a lattice.
Area of Science:
- Physics
- Statistical Mechanics
- Soft Matter Physics
Background:
- Absolute negative mobility (ANM) is a counterintuitive phenomenon observed in driven systems.
- Previous evidence for ANM relied on effective descriptions of nonequilibrium transport.
- A microscopic understanding of ANM has been lacking.
Purpose of the Study:
- To develop a microscopic theory for absolute negative mobility.
- To identify the conditions and mechanisms underlying ANM in a specific model.
- To explore the relationship between ANM and negative differential mobility.
Main Methods:
- Developing a theoretical model of an active tracer particle on a discrete lattice with mobile passive crowders.
- Employing a decoupling approximation for analytical calculations.
- Validating theoretical predictions through numerical simulations.
Main Results:
- The study analytically computes the tracer particle's velocity as a function of system parameters.
- The range of parameters for observing ANM is determined.
- The response of the environment to tracer displacement and the mechanism of ANM are clarified.
Conclusions:
- ANM can emerge from a microscopic model involving an active tracer and mobile crowders.
- The findings provide a fundamental understanding of ANM and its connection to negative differential mobility.
- This work bridges the gap between effective theories and microscopic descriptions of nonequilibrium transport.
