Article
Physics, Fluids & Plasmas
Naftali R. Smith, Pierre Le Doussal, Satya N. Majumdar, Gregory Schehr
Summary: This paper investigates an overdamped run-and-tumble particle in two dimensions with self-propulsion that stochastically rotates. By changing the coordinates, the problem is decomposed into two statistically independent one-dimensional problems, enabling the exact solutions for the particle's position distribution and steady-state distribution to be found.
Article
Physics, Fluids & Plasmas
Derek Frydel
Summary: This work investigates the entropy production rate, Pi, of the run-and-tumble model and focuses on its scaling with the persistence time tau. It is found that, in the limit of tau approaching infinity, Pi tends to zero, indicating equilibrium; while in the limit of tau approaching zero, Pi reaches its optimal value, indicating a departure from equilibrium.
Article
Physics, Multidisciplinary
Luca Angelani
Summary: Complex or hostile environments can hinder the movement capabilities of diffusive particles or active swimmers, leading to their immobilization. This study analyzes the dynamics of active particles in trapping regions and provides expressions for the probability distribution and mean trapping times of blocked particles. Different sizes of trapping regions are considered, from infinite to semi-infinite and finite intervals.
Article
Mechanics
Derek Frydel
Summary: This paper investigates the four-state run-and-tumble particle model at zero temperature and proposes an enhanced model by increasing the number of discrete velocities. The analysis reveals that fast particles tend to accumulate at the walls while slow particles deplete gradually.
Article
Physics, Fluids & Plasmas
Sergei Fedotov, Daniel Han, Alexey O. Ivanov, Marco A. A. da Silva
Summary: This paper introduces a run-and-tumble model with self-reinforcing directionality and rests, and derives a hyperbolic partial differential equation for the probability density of random-walk position. The research finds that the transition between superdiffusion and diffusion caused by the addition of a rest state depends on both the parameter representing the strength of self-reinforcement and the ratio between mean running and resting times.
Article
Chemistry, Multidisciplinary
Jiabin Luan, Peter F. Kuijken, Wen Chen, Danni Wang, Levy A. Charleston, Daniela A. Wilson
Summary: Biodegradable streamlined alginate hydrogel micromotors with a teardrop shape are fabricated by microfluidics, enabling high-throughput production and precise variation in size. By tuning the localization regions of catalysts, the micromotors exhibit improved propulsion efficiency and achieve distinct motion patterns.
Article
Physics, Multidisciplinary
Christian Maes, Kasper Meerts, Ward Struyve
Summary: This article discusses the problem of considering run-and-tumble particles (such as bacteria) in a quantum mechanical relation, and discusses their motion characteristics and trajectories, as well as their dependence on spin direction and spacetime parameters.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2022)
Article
Physics, Multidisciplinary
Prashant Singh, Saikat Santra, Anupam Kundu
Summary: This paper investigates the extreme value statistics of a run and tumble particle (RTP) in one dimension until its first passage to the origin. The joint distribution of the maximum displacement and the time at which this maximum is achieved is computed using the exact time-dependent propagators. The marginal distributions of the maximum displacement and the time are separately studied, and their asymptotic forms are found to depend on the initial conditions.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Physics, Multidisciplinary
Pascal Grange, Xueqi Yao
Summary: The study proposes a model of run-and-tumble particles on a line with a fertile site, where new particles are generated until a change in direction occurs. The system maintains parity invariance and the motion equations can be solved using density. At large time scales, the density of particles grows exponentially, depending on the fertility function and rate. The total density of particles reaches a stable state, with a local minimum at the fertile site.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Physics, Multidisciplinary
Luca Angelani
Summary: This study analyzes the behavior of run-and-tumble particles in one-dimensional finite domains under generic boundary conditions. The unified formulation allows for the treatment of various different boundary conditions and provides a general expression for the mean exit time.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2023)
Article
Physics, Fluids & Plasmas
Gennaro Tucci, Andrea Gambassi, Satya N. Majumdar, Gregory Schehr
Summary: This study investigates the statistical properties of a single run-and-tumble particle (RTP) reaching a fixed target, with or without resetting, in one spatial dimension. By analyzing the first-passage time distribution of a free RTP and introducing resetting, the research reveals interesting singular behaviors and rich phase diagrams in the (b, v) plane, providing important insights into the behavior of RTP under different conditions.
Article
Physics, Fluids & Plasmas
Sayantan Mitra, Dipa Saha, Ankur Sensharma
Summary: This article investigates site percolation in a distorted simple cubic lattice and finds that the percolation threshold increases with distortion when the connection threshold is equal to or greater than the lattice constant, while it first decreases and then steadily increases when the connection threshold is less than the lattice constant. The change in the fraction of occupied bonds explains the variation of the percolation threshold. It is also found that percolation in regular and distorted simple cubic lattices belongs to the same universality class, and this model is distinct from the site-bond percolation model.
Article
Mathematics, Applied
Jingyi Fu, Jiuyang Liang, Benoit Perthame, Min Tang, Chuhan Zhong
Summary: This paper proposes boundary conditions for a 2D confined run-and-tumble model for self-propelled particle populations. The model is used to describe the movement of micro-organisms between two parallel plates. Numerical and theoretical comparisons show that the model converges asymptotically to a confined Fokker-Planck model when the tumble is highly forward peaked and frequent enough.
MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES
(2023)
Article
Multidisciplinary Sciences
Remi Perrier, Yerali Gandica, Laura Hernandez
Summary: By introducing intrinsic noise proportional to the disagreement between interacting agents in the Axelrod model, we found that hesitation among agents prevents the system from reaching a frozen state in the thermodynamic limit. The behavior of the system differs when intrinsic noise affects agent variables compared to when it affects the network of interactions.
Article
Chemistry, Physical
Davide Breoni, Fabian Jan Schwarzendahl, Ralf Blossey, Hartmut Loewen
Summary: We study a one-dimensional three-state run-and-tumble model inspired by the bacterium Caulobacter crescentus. We analyze the stationary states of the system, compute the properties of cell distribution, explore the stability of the system, and investigate structure formation in a fully nonlinear system.
EUROPEAN PHYSICAL JOURNAL E
(2022)
Article
Biochemistry & Molecular Biology
Gerard C. L. Wong, Jyot D. Antani, Pushkar P. Lele, Jing Chen, Beiyan Nan, Marco J. Kuhn, Alexandre Persat, Jean-Louis Bru, Nina Molin Hoyland-Kroghsbo, Albert Siryaporn, Jacinta C. Conrad, Francesco Carrara, Yutaka Yawata, Roman Stocker, Yves Brun, Gregory B. Whitfield, Calvin K. Lee, Jaime de Anda, William C. Schmidt, Ramin Golestanian, George A. O'Toole, Kyle A. Floyd, Fitnat H. Yildiz, Shuai Yang, Fan Jin, Masanori Toyofuku, Leo Eberl, Nobuhiko Nomura, Lori A. Zacharoff, Mohamed Y. El-Naggar, Sibel Ebru Yalcin, Nikhil S. Malvankar, Mauricio D. Rojas-Andrade, Allon Hochbaum, Jing Yan, Howard A. Stone, Ned S. Wingreen, Bonnie L. Bassler, Yilin Wu, Haoran Xu, Knut Drescher, Jorn Dunkel
Summary: Bacterial biofilms are communities of bacteria that are essential to microbial physiology, with a complex relationship between single-cell behavior and collective community behavior. Biofilm microbiology, a relatively young field, has attracted physicists who use physics to study fundamental concepts in bacterial biofilms. The combination of physics and biology in this field exemplifies a new synthesis, rather than just a division of labor.
Article
Physics, Multidisciplinary
Babak Nasouri, Andrej Vilfan, Ramin Golestanian
Summary: The research derives a theorem for the lower bound on energy dissipation rate by microswimmers and proposes a new definition of energetic efficiency for microswimmers. Experimental results validate the theory.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Fanlong Meng, Daiki Matsunaga, Benoit Mahault, Ramin Golestanian
Summary: The study reveals that the collective behavior of magnetic microswimmers in a microfluidic channel can be analogized to Bose-Einstein condensation, achieved through a non-equilibrium phase transition, with the potential to generate exotic classical nonequilibrium phases of matter similar to those observed in quantum systems.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Saeed Mahdisoltani, Ramin Golestanian
Summary: This study shows that electrolytes driven by an external electric field exhibit scale invariance despite Debye screening. Long-range correlations result in a Casimir-like fluctuation-induced force between neutral boundaries that can be controlled by the electric field, behaving differently from other fluctuation-induced forces.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Physical
Vincent Ouazan-Reboul, Jaime Agudo-Canalejo, Ramin Golestanian
Summary: Biomolecular condensates in cells are often rich in catalytically active enzymes, particularly in large enzymatic complexes called metabolons. The self-organization of these enzymes may be explained by a combination of catalytic activity and chemotactic responses to gradients of substrates, leading to non-reciprocal interactions with exotic features. The study of phase separation in mixtures of catalytically active particles reveals a Michaelis-Menten-like dependence and transient oscillations, highlighting non-equilibrium organizing principles important for biological liquid-liquid phase separation.
EUROPEAN PHYSICAL JOURNAL E
(2021)
Article
Mechanics
Abdallah Daddi-Moussa-Ider, Babak Nasouri, Andrej Vilfan, Ramin Golestanian
Summary: The study reveals that the optimal propulsion strategy of microswimmers depends on their shape profile, which could be puller, pusher or neutral. Among all the modes of the shape function, only the third mode determines the swimming type of the optimal swimmer at leading order.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Multidisciplinary Sciences
Fanlong Meng, Rachel R. Bennett, Nariya Uchida, Ramin Golestanian
Summary: In this study, a theoretical framework connecting the dynamics of an individual cilium to the collective dynamics of a ciliary carpet via coarse graining is presented. The criteria controlling the selection of frequency and wave vector of stable metachronal waves of the cilia are uncovered and examined. Agent-based numerical simulations of arrays of cilia with hydrodynamic interactions show quantitative agreement with the predictions of the analytical framework.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Biology
David Hickey, Andrej Vilfan, Ramin Golestanian
Summary: The protruding geometry of cilia could be one of the reasons why so many receptors are located on cilia, as shown by comparing the capture rates. The study also highlights the advantage of combining motility with chemical reception.
Article
Physics, Multidisciplinary
Jaime Agudo-Canalejo, Tunrayo Adeleke-Larodo, Pierre Illien, Ramin Golestanian
Summary: This study explores the stochastic dynamics of two enzymes that are mechanically coupled to each other, demonstrating that this coupling can greatly enhance their catalytic rate. The findings suggest that enzymes, despite being on a molecular scale, can cooperate and improve performance in metabolic clusters.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Laura Collesano, Isabella Guido, Ramin Golestanian, Andrej Vilfan
Summary: This study focuses on a system that consists of a pair of microtubules clamped at one end, and investigates the static shapes and active dynamics of this system. The results show that the system transitions from a planar shape to a non-planar shape and then back to planar shape as the length ratio between the two filaments increases. The predicted shapes of the microtubule pairs agree with experimental observations. The dynamical system of this two-filament system can have stable fixed points or limit cycle oscillations, which resemble ciliary motility.
JOURNAL OF THE ROYAL SOCIETY INTERFACE
(2022)
Article
Multidisciplinary Sciences
Andrea Testa, Mirco Dindo, Aleksander A. Rebane, Babak Nasouri, Robert W. Style, Ramin Golestanian, Eric R. Dufresne, Paola Laurino
Summary: Living cells can harvest environmental energy to drive chemical processes. Here the authors design a minimal artificial system that achieves steady states at similar metabolic densities to microorganisms.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
Lorenzo Piro, Evelyn Tang, Ramin Golestanian
Summary: This study builds an analytical formalism for overdamped microswimmers on curved manifolds and arbitrary flows, revealing that the solution corresponds to the geodesics of a Randers metric. Swimmer performance following this Randers policy consistently outperforms a more direct policy, with relative gains growing significantly when specific structures related to either the geometry or the flow are exploited. Analysis of isochrone shape unveils features such as self-intersections, cusps, and abrupt nonlinear effects. This work establishes a connection between microswimmer physics and geodesics in generalizations of general relativity.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Medicine, General & Internal
Philip Bittihn, Lukas Hupe, Jonas Isensee, Ramin Golestanian
Summary: The effectiveness of regional containment strategies during COVID-19 pandemic is influenced by key parameters such as leakiness and regional structure. Lower proportion of cross-regional contacts and subdivision of regions can lead to more efficient epidemic control without impacting local socioeconomic freedom.
Meeting Abstract
Biophysics
Evelyn M. Tang, Jaime Agudo-Canalejo, Ramin Golestanian
BIOPHYSICAL JOURNAL
(2021)
Article
Physics, Multidisciplinary
Saeed Mahdisoltani, Riccardo Ben Ali Zinati, Charlie Duclut, Andrea Gambassi, Ramin Golestanian
Summary: The study presents an unconventional mechanism for interactions within biological systems, proposing that self-organization is driven by the interaction of polarity particles via chemical signals. The research utilizes an exact stochastic formulation and dynamical renormalization group analysis to reveal the emergent Galilean symmetry and dynamical scaling exponents at the critical point. These findings indicate superdiffusive density fluctuations and non-Poissonian number fluctuations that can determine the large-scale behavior of cell colonies and tissues.
PHYSICAL REVIEW RESEARCH
(2021)