1
|
Miranda JP, Locatelli E, Valeriani C. Self-Organized States from Solutions of Active Ring Polymers in Bulk and under Confinement. J Chem Theory Comput 2024; 20:1636-1645. [PMID: 38153343 DOI: 10.1021/acs.jctc.3c00818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
In the present work, we study, by means of numerical simulations, the structural and dynamical behavior of a suspension of active ring polymers in bulk and under lateral confinement. At high activity, when changing the distance between the confining planes and the polymers' density, we identify the emergence of a self-organized dynamical state, characterized by the coexistence of slowly diffusing clusters of rotating disks and faster rings moving in between them. We further assess that self-organization is robust in a range of polymer sizes, and we identify a critical value of the activity, necessary to trigger cluster formation. This system has distinctive features resembling at the same time polymers, liquid crystals, and active systems, where the interplay between activity, topology, and confinement leads to a spontaneous segregation in an initially one-component solution.
Collapse
Affiliation(s)
- Juan Pablo Miranda
- Dep. Est. de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, 28040 Madrid, Spain
- GISC - Grupo Interdisciplinar de Sistemas Complejos, 28040 Madrid, Spain
| | - Emanuele Locatelli
- Department of Physics and Astronomy, University of Padova, 35131 Padova, Italy
- INFN, Sezione di Padova, via Marzolo 8, I-35131 Padova, Italy
| | - Chantal Valeriani
- Dep. Est. de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, 28040 Madrid, Spain
- GISC - Grupo Interdisciplinar de Sistemas Complejos, 28040 Madrid, Spain
| |
Collapse
|
2
|
Kalinay P, Slanina F. Ratchet effect in an asymmetric two-dimensional system of Janus particles. Phys Rev E 2023; 108:014606. [PMID: 37583160 DOI: 10.1103/physreve.108.014606] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/28/2023] [Indexed: 08/17/2023]
Abstract
We consider a disk-like Janus particle self-driven by a force of constant magnitude f, but an arbitrary direction depending on the stochastic rotation of the disk. The particle diffuses in a two-dimensional channel of varying width 2h(x). We applied the procedure mapping the 2+1-dimensional Fokker-Planck equation onto the longitudinal coordinate x; the result is the Fick-Jacobs equation extended by the spatially dependent effective diffusion constant D(x) and an additional effective potential -γ(x), derived recursively within the mapping procedure. Unlike the entropic potential ∼lnh(x), γ(x) becomes an increasing or decreasing function also in periodic channels, depending on the asymmetry of h(x) and thus it visualizes the net force driving the ratchet current. We demonstrate the appearance of the ratchet effect on a trial asymmetric channel; our theory is verified by a numerical solution of the corresponding Fokker-Planck equation. Isotropic driving force f results in the monotonic decrease of the ratchet current with a growing ratio α=D_{R}/D_{T} of the rotation and the translation diffusion constants; asymptotically going ∼1/α^{2}. If we allow anisotropy of the force, we can observe the current reversal depending on α.
Collapse
Affiliation(s)
- Pavol Kalinay
- Institute of Physics, Slovak Academy of Sciences, Dúbravska cesta 9, 84511, Bratislava, Slovakia
| | - František Slanina
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, CZ-18200, Praha, Czech Republic
| |
Collapse
|
3
|
Muhsin M, Sahoo M. Inertial active ratchet: Simulation versus theory. Phys Rev E 2023; 107:054601. [PMID: 37329079 DOI: 10.1103/physreve.107.054601] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 04/21/2023] [Indexed: 06/18/2023]
Abstract
We present the inertial active dynamics of an Ornstein-Uhlenbeck particle in a piecewise sawtooth ratchet potential. Using the Langevin simulation and matrix continued fraction method (MCFM), the particle transport, steady-state diffusion, and coherence in transport are investigated in different parameter regimes of the model. Spatial asymmetry is found to be a key criterion for the possibility of directed transport in the ratchet. The MCFM results for net particle current of overdamped dynamics of the particle agree well with the simulation results. The simulated particle trajectories for the inertial dynamics and the corresponding position and velocity distribution functions reveal that the system passes through an activity-induced transition in the transport from the running phase to the locked phase of the dynamics. This is further corroborated by the mean square displacement (MSD) calculations, where the MSD gets suppressed with increase in the persistent duration of activity or self-propulsion in the medium and finally approaches zero for a very large value of self propulsion time. The nonmonotonic behavior of the particle current and Péclet number with self-propulsion time confirms that the particle transport and its coherence can be enhanced or reduced by fine tuning the persistent duration of activity. Moreover, for intermediate ranges of self-propulsion time as well as mass of the particle, even though the particle current shows a pronounced unusual maximum with mass, there is no enhancement in the Péclet number, instead the Péclet number decreases with mass, confirming the degradation of coherence in transport.
Collapse
Affiliation(s)
- M Muhsin
- Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram-695581, India
| | - M Sahoo
- Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram-695581, India
| |
Collapse
|
4
|
Kalinay P. Transverse dichotomic ratchet in a two-dimensional corrugated channel. Phys Rev E 2022; 106:044126. [PMID: 36397573 DOI: 10.1103/physreve.106.044126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
A particle diffusing in a two-dimensional channel of varying width h(x) is considered. It is driven by a force of constant magnitude f, but random orientation across the channel. We suggest the projection technique to study the ratchet effect appearing in this system. Reducing the transverse coordinate, as well as the orientation of the force in the full-dimensional Fokker-Planck equation, we arrive at the generalized Fick-Jacobs equation, describing dynamics of the system in the longitudinal coordinate x only. The additional effective potential -γ(x), calculated within the mapping procedure, exhibits an increasing or decreasing part in the channel shaped by an asymmetric periodic h(x), which determines the appearing ratchet current. As shown on a specific example, random driving in the transverse direction is much more effective than that in the longitudinal direction, at least for quickly flipping orientation of the force. Also, the transverse and the longitudinal driving push the rectified current in opposite directions along the same channel.
Collapse
Affiliation(s)
- Pavol Kalinay
- Institute of Physics, Slovak Academy of Sciences, Dúbravska cesta 9, 84511, Bratislava, Slovakia
| |
Collapse
|
5
|
Kalinay P, Slanina F. Dichotomic ratchet in a two-dimensional corrugated channel. Phys Rev E 2021; 104:064115. [PMID: 35030943 DOI: 10.1103/physreve.104.064115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/29/2021] [Indexed: 06/14/2023]
Abstract
We consider a particle diffusing in a two-dimensional (2D) channel of varying width h(x). It is driven by a force of constant magnitude f but random orientation there or back along the channel. We derive the effective generalized Fick-Jacobs equation for this system, which describes the dynamics of such a particle in the longitudinal coordinate x. Aside from the effective diffusion coefficient D(x), our mapping also generates an additional effective potential -γ(x) added to the entropic potential -log[h(x)]. It acquires an increasing or decreasing component in asymmetric periodic channels, and thus it explains appearance of the ratchet current. We study this effect on a trial example and compare the results of our true 2D theory with a commonly used effective one-dimensional description; the data are verified by the numerical solution of the full 2D problem.
Collapse
Affiliation(s)
- Pavol Kalinay
- Institute of Physics, Slovak Academy of Sciences, Dúbravska cesta 9, 84511, Bratislava, Slovakia
| | - František Slanina
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, CZ-18221, Prague, Czech Republic
| |
Collapse
|
6
|
de Castro P, M Rocha F, Diles S, Soto R, Sollich P. Diversity of self-propulsion speeds reduces motility-induced clustering in confined active matter. SOFT MATTER 2021; 17:9926-9936. [PMID: 34676388 DOI: 10.1039/d1sm01009c] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Self-propelled swimmers such as bacteria agglomerate into clusters as a result of their persistent motion. In 1D, those clusters do not coalesce macroscopically and the stationary cluster size distribution (CSD) takes an exponential form. We develop a minimal lattice model for active particles in narrow channels to study how clustering is affected by the interplay between self-propulsion speed diversity and confinement. A mixture of run-and-tumble particles with a distribution of self-propulsion speeds is simulated in 1D. Particles can swap positions at rates proportional to their relative self-propulsion speed. Without swapping, we find that the average cluster size Lc decreases with diversity and follows a non-arithmetic power mean of the single-component Lc's, unlike the case of tumbling-rate diversity previously studied. Effectively, the mixture is thus equivalent to a system of identical particles whose self-propulsion speed is the harmonic mean self-propulsion speed of the mixture. With swapping, particles escape more quickly from clusters. As a consequence, Lc decreases with swapping rates and depends less strongly on diversity. We derive a dynamical equilibrium theory for the CSDs of binary and fully polydisperse systems. Similarly to the clustering behaviour of one-component models, our qualitative results for mixtures are expected to be universal across active matter. Using literature experimental values for the self-propulsion speed diversity of unicellular swimmers known as choanoflagellates, which naturally differentiate into slower and faster cells, we predict that the error in estimating their Lcvia one-component models which use the conventional arithmetic mean self-propulsion speed is around 30%.
Collapse
Affiliation(s)
- Pablo de Castro
- Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Avenida Blanco Encalada 2008, Santiago, Chile.
| | | | - Saulo Diles
- Faculdade de Física, Universidade Federal do Pará, Campus Salinópolis, Rua Raimundo Santana Cruz S/N, 68721-000, Salinópolis, Pará, Brazil
| | - Rodrigo Soto
- Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Avenida Blanco Encalada 2008, Santiago, Chile.
| | - Peter Sollich
- Disordered Systems Group, Department of Mathematics, King's College London, London, UK
- Institut für Theoretische Physik, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| |
Collapse
|