Article
Physics, Multidisciplinary
Pin-chuan Chen, Klaus Kroy, Frank Cichos, Xiangzun Wang, Viktor Holubec
Summary: Perception-reaction delays can cause microswimmers to spontaneously circle around a fixed target particle. In this study, Brownian-dynamics simulations of active particles in a plane were used to investigate a many-body version of this experiment. Short delays led to the formation of a hexagonal crystallite around the target, while longer delays resulted in the bifurcation to a chiral dynamical phase similar to that of a single active particle. Different angular velocities at different distances from the target induced increasing shear stresses with increasing delay. By exciting shear bands, the rotating crystallite shook and intermittently broke. For long delays, it detached from the target and circled around it as a compact spinning satellite, trembling from what could be called tidal quakes.
Article
Biochemical Research Methods
Koohee Han, Alexey Snezhko
Summary: This study demonstrates programmable control of the direction of self-organized vortex motion by driving microscopic ferromagnetic rollers with an alternating magnetic field, allowing for remote control of a micro-pump architecture to switch fluid transport direction on demand.
Article
Physics, Multidisciplinary
Fu-Jun Lin, Jing-Jing Liao, Bao-Quan Ai
Summary: The crystallization dynamics of chiral active colloids were numerically explored. It was observed that chiral colloids with large angular velocity could be localized by self-trapping, promoting the formation of hexagonal crystal structures. The competition between chirality and coupling strength resulted in a transition between liquid and solid regimes. With increasing chirality, the transition points shifted greatly towards the weak coupling region. The hexagonal structure appeared to be more tenacious and difficult to melt, leading to a shrinking solid-liquid coexistence region in the phase diagram. In the low rotational speed region, the system exhibited global ordering but experienced significant diffusion, resulting in structural ordering before dynamical freezing.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2022)
Article
Chemistry, Physical
Zhan Ma, Ran Ni
Summary: This study reveals that a large torque in chiral active particles interrupts the conventional gas-liquid-like motility-induced phase separation and generates a dynamical clustering state.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Jose Martin-Roca, Raul Martinez, Lachlan C. Alexander, Angel Luis Diez, Dirk G. A. L. Aarts, Francisco Alarcon, Jorge Ramirez, Chantal Valeriani
Summary: The study focuses on the onset of Motility Induced Phase Separation (MIPS) in a two-dimensional system of Active Brownian Particles (ABPs) through molecular dynamics simulations. The phase diagram of the system is found to be determined by density and Peclet number. The effects of translational noise and particle overlap are studied, with the use of a stiffer potential and observation of dynamical features being more efficient in detecting MIPS.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Jens Bickmann, Stephan Broeker, Julian Jeggle, Raphael Wittkowski
Summary: We consider chirality in active systems by studying the phase behavior of planar systems of interacting Brownian circle swimmers. We derive a predictive field theory that describes the collective dynamics of the circle swimmers and predict the suppression of motility-induced phase separation by the angular propulsion of the particles.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Guo-hao Xu, Teng-Chao Li, Bao-quan Ai
Summary: This study proposes a method for the chiral separation of chiral active particles using a spiral-shaped obstacle, enabling the selective trapping and separation of mixed chiral particles.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2022)
Article
Physics, Multidisciplinary
Jing-Ran Li, Wei-jing Zhu, Jia-Jian Li, Jian-Chun Wu, Bao-Quan Ai
Summary: In this numerical study, the rotation of a symmetric gear driven by chiral particles in a two-dimensional box with periodic boundary conditions is investigated. Surprisingly, the symmetric gear can experience macroscopic directional rotation due to the microscopic random motion of chiral active particles. The alignment interactions between particles and the chirality of active particles play crucial roles in determining the direction and speed of the gear's rotation.
NEW JOURNAL OF PHYSICS
(2023)
Article
Chemistry, Physical
Guo-Jun Liao, Sabine H. L. Klapp
Summary: Using BD simulations, we investigated the self-organization of a monolayer of chiral active particles with dipolar interactions. Despite performing simulations at high dipolar coupling strength and low density, we observed phenomena such as vortex formation, phase separation, and flocking transitions in the system. We further studied the dynamics of simple ring structures under the impact of self-propulsion to understand the appearance and disappearance of vortices.
Article
Physics, Multidisciplinary
Kim L. Kreienkamp, Sabine H. L. Klapp
Summary: This study investigates the impact of non-reciprocity on the collective behavior of a system of chiral active matter. The research suggests that non-reciprocity can change the stability and instability of the system and affect the relative orientation of flocks, highlighting the significance of non-reciprocity in understanding the emergent collective dynamics of chiral active matter systems.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
Ming Han, Michel Fruchart, Colin Scheibner, Suriyanarayanan Vaikuntanathan, Juan J. de Pablo, Vincenzo Vitelli
Summary: Active fluids exhibit equilibrium-like properties when their fluctuating and activated degrees of freedom are statistically decoupled. The emergence of a single effective temperature in these systems parameterizes both the equation of state and Boltzmann statistics. By developing a theory for the fluctuating hydrodynamics of these non-equilibrium fluids and validating it through large-scale molecular dynamics simulations, the microscopic origin of odd viscosities and stress fluctuations in parity-violating fluids is illuminated.
Article
Multidisciplinary Sciences
Jens Grauer, Falko Schmidt, Jesus Pineda, Benjamin Midtvedt, Hartmut Loewen, Giovanni Volpe, Benno Liebchen
Summary: Active matter can spontaneously form complex patterns and assemblies via a one-way energy flow from the environment into the system. The authors demonstrate that a two-way coupling, where active particles act back on the environment, can give rise to novel superstructures, named as active droploids.
NATURE COMMUNICATIONS
(2021)
Article
Mathematics
Dorota Bors, Robert Stanczy
Summary: The analysis focuses on the modeling of steady states in a nonautonomous dynamical system describing the interaction of a cloud of particles. Two statistical distributions, Maxwell-Boltzmann and classical Michie-King, are considered. The phenomenon of critical mass relative to temperature is observed, and a singular limit result for an admissible range of parameters is established.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2023)
Article
Chemistry, Physical
Venkata Manikantha Sai Ganesh Tanuku, Peter Vogel, Thomas Palberg, Ivo Buttinoni
Summary: Researchers found that two-dimensional motion of silica-gold Janus particles exhibit straight motion in obstacle-free regions and sudden reorientations upon collision with particle clusters. They propose that these scattering events are caused by the interplay of electrohydrodynamic flows, self-propulsion, and local torques. The combination of directed motion and sudden reorientations leads to active trajectories resembling the run-and-tumble behavior of biological microswimmers.
Article
Engineering, Electrical & Electronic
Lanre Akinyemi, Mustafa Inc, Mostafa M. A. Khater, Hadi Rezazadeh
Summary: In this work, the exact traveling wave solutions of the (2 + 1)-dimensional Chiral nonlinear Schrodinger equation were studied using the generalized auxiliary equation method. The results showed that the aforementioned model has wide applications in quantum field theory, and the suggested technique provides various types of solutions.
OPTICAL AND QUANTUM ELECTRONICS
(2022)