Article
Multidisciplinary Sciences
Stephen Williams, Raphael Jeanneret, Idan Tuval, Marco Polin
Summary: Understanding how order emerges in active matter can help control microscopic objects on a macroscopic scale. This study demonstrates the control of passive microscopic particles in the presence of motile algae and boundary-induced accumulation of microswimmers, and the experimental realization of de-mixing of an active-passive suspension, providing a way to manipulate colloidal objects through controlled activity fields.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Pierre Rizkallah, Alessandro Sarracino, Olivier Benichou, Pierre Illien
Summary: Absolute negative mobility (ANM) refers to the situation where the average velocity of a driven tracer is opposite to the direction of the driving force. In this study, a microscopic theory for ANM is provided by considering an active tracer particle on a lattice populated with mobile passive crowders. The analytical calculation of the tracer particle's velocity as a function of system parameters is conducted using a decoupling approximation, and the results are compared with numerical simulations. The range of parameters where ANM can be observed is determined, the response of the environment to the tracer's displacement is characterized, and the mechanism underlying ANM and its relationship with negative differential mobility are clarified.
PHYSICAL REVIEW LETTERS
(2023)
Article
Engineering, Chemical
Deepak Mangal, Jacinta C. Conrad, Jeremy C. Palmer
Summary: The study found that steric and hydrodynamic interactions hinder particle diffusivity under quiescent conditions and enhance longitudinal dispersion under flow. Additionally, the presence of hydrodynamic interactions leads to a power-law increase in the longitudinal dispersion coefficient with Pe due to spatial variations in the fluid velocity. Furthermore, simulations revealed that longitudinal particle dispersion coefficients behave similarly in 2D and 3D when hydrodynamic interactions are included.
Article
Chemistry, Physical
F. Orts, M. Maier, M. Fuchs, G. Ortega, E. M. Garzon, A. M. Puertas
Summary: The dynamics of a tracer particle in a bath of quasi-hard colloidal spheres is investigated using Langevin dynamics simulations and mode coupling theory. The study reveals that the size of the tracer particle has a significant impact on its motion, as well as on the dynamics of the bath particles.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Koushik Goswami, Rajarshi Chakrabarti
Summary: We propose a model to investigate the motion of a single active particle in a heterogeneous environment. By describing the active particle using the Ornstein-Uhlenbeck process (OUP) and incorporating heterogeneity in a thermal bath using diffusing diffusivity and switching diffusion models, we explore the essential dynamical properties of the particle for its one-dimensional motion. Additionally, we demonstrate how the dynamical behavior is controlled by dynamical variables associated with active noise.
Article
Chemistry, Physical
Ke Cheng, Peng Liu, Mingcheng Yang, Meiying Hou
Summary: This study experimentally verifies the exponential time correlation characteristic of the active noise experienced by passive objects in an active granular bath. However, the active noise in this system is non-Gaussian.
Article
Chemistry, Physical
Alireza Shakerpoor, Elijah Flenner, Grzegorz Szamel
Summary: Researchers derived a distribution function for the position of a tagged active particle in a system of interacting active particles, revealing a new effective temperature that is determined by the ratio of self-diffusion and tagged particle mobility coefficients.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
Remi Goerlich, Luis Barbosa Pires, Giovanni Manfredi, Paul-Antoine Hervieux, Cyriaque Genet
Summary: This study proposes the use of a correlated noise bath to drive an optically trapped Brownian particle that mimics active biological matter. By controlling different parameters with unprecedented accuracy, the researchers are able to reach strongly correlated regimes that are not easily accessible in real active matter. They found that by adjusting the correlation time of the noise as a control parameter, transitions between two nonequilibrium steady states can be triggered without expending work but with a calorific cost. The measured heat production is directly proportional to the spectral entropy of the correlated noise, similar to Landauer's principle.
Article
Physics, Multidisciplinary
Omer Granek, Yariv Kafri, Julien Tailleur
Summary: The study found that the symmetry of the tracer affects the long-time tails of damping and noise correlations, with symmetric tracers leading to normal diffusion and finite friction while asymmetric tracers induce ratchet effects causing superdiffusion and growing friction. Additionally, for small symmetric tracers, the active contribution to friction becomes negative, enhancing motion rather than opposing it.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Fluids & Plasmas
K. Bialas, J. Spiechowicz
Summary: Understanding the role of active fluctuations, which are inherently nonequilibrium, is both a hot topic and a major challenge in physics. This opens up a new landscape of phenomena that are absent when only thermal fluctuations are present. Recent studies have shown that the transport of free particles induced by white Poisson shot noise can be significantly enhanced when subjected to a periodic potential. This research extends the original predictions, investigates the impact of active noise statistics, and explains the mechanisms for the enhancement of free-particle transport.
Article
Physics, Fluids & Plasmas
Koushik Goswami, Rajarshi Chakrabarti
Summary: We studied the dynamics of an overdamped Brownian particle subject to Poissonian stochastic resetting in a nonthermal bath, characterizing by Poisson white noise and Gaussian noise. Our analysis revealed a double exponential spatial distribution and showed the existence of an optimal resetting rate that minimizes mean first-arrival time to the sink. The study also explored the effects of Poissonian noise strength and sink strength on the system behavior.
Article
Physics, Multidisciplinary
Tao Huang, Chunhua Zeng, Yong Chen
Summary: This study investigates the collective diffusion behavior of a two-dimensional anisotropic liquid system through molecular dynamics simulations. The results show that the long-time diffusion behavior of nearly spherical anisotropic particles is similar to that of isotropic liquids, while their anisotropic properties are mainly reflected in the spatial correlation of particle orientations and mid-range diffusion behavior.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Jian Zhang, Tao Huang, Guoqing Xu, Yong Chen
Summary: In this study, the density fluctuation in two-dimensional mixtures of active and passive particles was investigated using Brownian dynamics simulations. The boundary of motility-induced phase separation was determined by the transition from unimodal to bimodal density distribution. It was observed that the fluctuation exponent rapidly increases near the boundary of phase separation in the plane of density and Peclet number. When phase separation occurs, the fluctuation exponent remains approximately constant at 0.85.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Koushik Goswami
Summary: By modeling the active noise as a generalized form of Ornstein-Uhlenbeck process, the dynamics and work distribution of a Brownian particle in a Gaussian active bath are theoretically investigated, revealing an asymptotic approach to a superdiffusive regime. Two protocols for performing work on the system are considered, with exact expressions for the probability distribution function of work obtained, showing anomalous scaling with time. Fluctuation relations of work are studied, revealing a non-conventional FR emerging in the long-time limit, and recovering known results for the usual OUP bath.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2021)
Article
Mathematics, Applied
Minsoo Kim, Mamoru Okamoto, Yusuke Yasugahira, Shinpei Tanaka, Satoshi Nakata, Yasuaki Kobayashi, Masaharu Nagayama
Summary: This study investigates the collective behaviors of oil droplets floating on a surfactant solution in a narrow circular channel, both experimentally and numerically. A mathematical model is introduced to explain the transient oscillations and cluster formation of the droplets, showing successful reproduction of these experimental findings. The long-range interaction due to the global concentration profile of the solution is argued to be sufficient for the cluster formation.
PHYSICA D-NONLINEAR PHENOMENA
(2021)