DOCSLIB.ORG

Poster Active Matter Morphological and Dynamical Properties Of

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Poster Active Matter Morphological and Dynamical Properties Of Poster Active Matter Morphological and dynamical properties of semiflexible filaments driven by molecular motors Abhishek Chaudhuri IISER Mohali We consider an explicit model of a semiflexible filament moving in two dimensions on a gliding assay of motor proteins, which attach to and detach from filament segments stochastically, with a detachment rate that increases with the increase of local load force. Attached motor proteins move along the filament to one of its ends with a velocity that varies nonlinearly with the motor protein extension. The resultant force on the filament drives it out of equilibrium. We characteri e the nonequilibrium conformations of the polymer comparing its end!to-end distribution with that of the equilibrium filament. We show that subtle changes in the local load dependence of detachment rate and active velocity of motor proteins lead to dramatic di"erence in the end!to-end distribution. The center of mass of the polymer shows a series of crossovers between ballistic and diffusive motion, controlled by its inertial, orientational and speed relaxation time scales. Poster Active Matter Trajectory of a confined active particle in presence of other passive and active particles Ahana P IIT Madras #nderstanding the hydrodynamic interaction between active and passive particle is crucial in a number of applications, ranging from artificial drug delivery to mixing in microfluidic channels. $iological systems where microswimmers swimming next to passive objects are also very common. Presence of a passive object affects the self- propulsion dynamics of the microswimmers and lead to complex behaviour. 'ere we investigate, how the dynamics of a micro swimmer under confinement, is modified in presence of a passive colloidal particle.(icroswimmers are modelled using squirmer model and lattice $oltzmann simulations are used to construct the trajectories of micro swimmer and colloidal particle. &assive colloid is placed at different location in the domain to study the hydrodynamic interaction between the swimmer and the colloid. )t is *nown that microswimmers can carry passive particles which is even larger than the swimmer it self. )nteraction potential between the swimmer and colloid can result in diverse scenarios. Therefore we also investigate the e"ect of soft sphere potential between the particle in determining the dynamics of the microswimmers. The scenario has been generalised by replacing the passive particle with a second squirmer of different strength. Poster Active Matter Autophoretic propulsion in complex fluids Akash Choudhary IIT Madras +elf-propelling ,anus particles generate concentration gradients along their surface by exploiting the asymmetry in surface activity. This gives rise to a `slip. at the particle surface, which propels the particle without the requirement of external concentration gradients. )n this wor*, we study the influence of viscoelasticity (second!order!fluid model0 and shear! thinning/thic*ening /power!law!fluid model0 on the slip and mobility of an axisymmetric active particle. #sing matched asymptotic expansions, we provide an analytical expression for the modification of slip. #sing reciprocal theorem, we demonstrate the influence of fluid rheology on the particle mobility. Poster Active Matter Clustering dynamics of active particles in an explicit solvent Arabinda era JNCASR Bangalore We adopted a hybrid method to study the dynamics of active particles (colloid0 embedded in a solvent bath. 'ydrodynamics in the solvent has been implemented via multi! particle collision dynamics, which is a coarse!grained method for simulating fluids. Dynamics due to colloid!colloid and colloid!solvent passive interactions, incorporated via variants of the 3ennard!,ones potential, were taken care of through an appropriate molecular dynamics /(20 method. )n this wor*, the self!propulsion in the colloids is introduced via the well!*nown 4icse* model. #sing this model, we obtained important results on the effects of self-propulsion or activity on the clustering and transport properties of the colloids in the presence of hydrodynamics. We observed that the clustering of active colloids is more favorable in the presence of hydrodynamics. Poster Active Matter !stimation of internal po"er distribution in sperm flagella from beat pattern measurements Ash"in #andagiri IIT Bombay +permatozoa use slender elastic appendages *nown as flagella to propel themselves in a viscous fluid. The flagellar beat is driven by the action of AT&!powered dynein motors on microtubule filaments inside the flagellum. We use experimentally measured beat patterns to extract the bending stiffness and internal active power distribution in the flagellum. 'ead! tethered mouse sperm are imaged with high!speed, high! resolution microscopy to capture approximately 40 flagellar beat cycles per sample. An image processing routine developed in (AT3A$ is used to extract flagellar centrelines from the movies. Proper Orthogonal Decomposition /&720 is used to compute the dominant shape modes of the flagellar beat. A single representative beat cycle is constructed by averaging the time!dependent coe8cients of the modes. 9urther, error propagation is used to calculate the local variance in the flagellar beat shapes from the variance in the mode coe8cients. 'ydrodynamic forces and dissipation by the flagellum during the beat are calculated from the local velocity using resistive force theory. The flagellum is then treated as a slender, flexible, inextensible rod immersed in a viscous fluid that is driven by internal forces and moments. Kirchhoff rod theory is applied to formulate local conservation laws and compute the local active power from the hydrodynamic force distribution. 9urther, a global energy balance is used to estimate the bending stiffness of the flagellum. This method is applied to study the role of the ;<)+& family of proteins on the flagellar beat in mouse sperm. (ouse sperm from ;<)+&!*noc*out mutants are compared to wild!type samples. We find that clear differences in the flagellar *inematics can be discerned from the &72 and representative beat cycles of the wild!type and mutant genotypes. The active power calculations are used to further investigate the source of these differences. Poster Active Matter Mimicking Critical Casimir $orces in sessile "ater droplets asudev %oy& IIT Madras ;ritical ;asimir forces arise in binary liquds when the temperature of the environment is locally raised just above the demixing point such that in general the liquids remain mixed while the heated location exhibits demixing. There are density fluctuations in the heated region leading to interesting effects. We mimic this effect by thin layer of sessile water droplet when a tightly focused laser beam heats the bottom substrate raising the temperature of the locality to around the boiling point of water. We show that as a particle trapped on the air!water interface of a sessile droplet is brought very close to the edge, it starts to exhibit rapid motion quite akin to heavy density fluctuations, which is even superdiffusive in nature. These density fluctuations are further accentuated by a possible low pressure region right above the heated region which allows the heated water to vapori e rapidly. The critical casimir forces are an analog of the regular casimir forces where vacuum fluctuations lead to forces between surfaces. Poster Active Matter Re'entrant motility induced phase separation in nematically aligning active polar particles iplab hattacherjee I P Bh!banes"ar We present a numerical study of the phase behavior of repulsively interacting active polar particles that align their active velocities nematically. The amplitude of the active velocity, and the noise in its orientational alignment control the active nature of the system. At high values of orientational noise, the structural fluid undergoes a continuous nematic!isotropic transition in active orientation. This transition is well separated from a color ;lustering transition observed at lower noise strengths. The clustering is characteri ed by the formation of high density hexatic clusters. With increasing activity, the system undergoes a re!entrant fluid! clustering- fluid transition. The melting of hexatic is associated with fragmentation of large local polar clusters and creation of grain boundaries. The collective dynamics within the clustering phase progresses with sliding clusters, jamming and lane formation. Poster Active Matter Topological defects in active nematics C (anthan IIT Madras Active nematics is a promising model fluid towards understanding of active matter, for eg: suspensions of microtubule bundles with *inesin motors, colonies of bacteria li*e E.coli or collective motion of human cells in the case of cancer invasion. Typical to liquid crystals, defects is a generic feature of active nematics as well and it plays a major role in controlling dynamics of the fluid. An interesting example is the role of defects in cell extrusion from a cell monolayer, which is an important phase in cancer invasion. #nli*e in passive nematics, defects in active systems are motile. +o they are generated, travel and get annihilated. <ecent experimental studies in a star!shaped geometry with 2D active systems showed that stress around a @1/2 defect plays major role in cell extrusion.We use continuum approximations to model active nematics and solve for flow field and director field. The stress fields around @A1? defect and !A1? defect for an extensile system and a contractile
Load more

Recommended publications
  • Poster Abstracts
    Poster abstracts P01 Penetration of a model membrane by a self-propelled active A. Daddi-Moussa-Ider particle P02 The squirmer model and beyond F. Fadda P03 Theoretical Investigation of Structure Formation by Magne- V. Telezki totactic Bacteria P04 Active Nematics Formed by Bacteria in Patterned R. Koizumi Chromonics P05 Self-propulsion of Camphor Symmetric Interfacial Swim- D. Boniface mers P06 Microswimmers self-propelled by Thermophoresis S. Roca-Bonet P07 Active Brownian filaments in dilute solution A. Mart´ın-Gomez´ P08 Scattering of E. coli at surfaces M. Mousavi P09 Light dependent motility of microalgae induces pattern for- A. Fragkopoulos mation in confinement P10 Longwave nonlinear theory for chemically active droplet di- M. Abu Hamed vision instability P11 Bead-spring modelling microswimmers S. Ziegler P12 Light-driven Janus microswimmers in dense colloidal ma- T. Huang trix P13 Active Brownian Particles in Crowded Media A. Liluashvili P14 Evolution in range expansions with competition at rough S. Chu boundaries P15 Mode-Coupling Theory for Active Brownian Particles J.Reichert P16 Structure and dynamics of a self-propelled semiflexible fil- S. P. Singh ament P17 IHRS Biosoft T. Auth P18 IHRS Biosoft T.Auth P19 Pairing, waltzing and scattering of chemotactic active col- S. Saha loids P20 Instability in settling array of discs R. Chajwa P21 Self-propelled particles in anisotropic environments A. R. Sprenger P22 A phase field crystal approach to active systems with inertia D. Arold P23 Ring polymers are much stronger depleting agents than lin- I. Chubak ear ones P24 Enhanced rotational diffusion of squirmers in viscoelastic K. Qi fluids P25 Dynamics of confined phoretic colloids K.
    [Show full text]
  • A Catalogue of Bacterial Swarm Behaviour
    RESEARCH HIGHLIGHTS Nature Reviews Physics | https://doi.org/10.1038/s42254-020-0172- x | Published online 7 April 2020 ACTIVE MATTER A catalogue of bacterial swarm behaviour Even under adverse conditions length of its cells can be controlled such as starvation, some bacteria by known genetic manipulations. can efficiently expand and move This controllability enabled their colonies by rapidly migrating Be’er et al. to select between four en masse, a process known as cell aspect ratios for their colonies. Credit: Adapted from Be’er, A. et al. Commun. Phys. swarming. Although bacterial They recorded the motion of the 3, 66 (2020), CC BY 4.0 colonies have been studied by colonies on a surface for a range of physicists for years, there is not colony densities. Very sparse colonies of similar self-propelled rods with yet a complete picture of how the of B. subtilis do not move, whereas known interactions indicates that physical properties of the cells, very dense colonies are jammed. the bacterial behaviour is domina- such as their shape, govern the However, for intermediate densities, ted by short-range interactions. behaviour of the swarm. Now, cell aspect ratio plays a role in In contrast to long cells, shorter writing in Communications Physics, the colony’s behaviour. Longer cells swarm in clusters that have Avraham Be’er and colleagues fill cells form high-density clusters uniform density across the surface in another piece of the puzzle, of moving cells that are separated (lower panels of figure). Be’er et al. cataloguing the swarming behaviour by low- density regions containing posit that this uniform density of the rod-shaped Bacillus subtilis, only immobile cells (upper left arises because long-range hydro- as a function of the density of panel of figure).
    [Show full text]
  • Ant Colony Optimization
    Morphogenetic Engineering: Biological Development as a new model of Programmed Self-Organization René Doursat CNRS – Complex Systems Institute, Paris – Ecole Polytechnique Susan Stepney, York Stanislaw Ulam [said] that using a term like nonlinear science is like referring to the bulk of zoology as the study of non-elephant animals. The elephant in the room here is the classical Turing machine. Unconventional computation is a similar term: the study of non-Turing computation. The classical Turing machine was developed as an abstraction of how human “computers”, clerks following predefined and prescriptive rules, calculated various mathematical tables. Unconventional computation can be inspired by the whole of wider nature. We can look to physics (...), to chemistry (reaction-diffusion systems, complex chemical reactions, DNA binding), and to biology (bacteria, flocks, social insects, evolution, growth and self-assembly, immune systems, neural systems), to mention just a few. PARALLELISM – INTERACTION – NATURE → COMPLEX SYSTEMS 2 COMPLEX SYSTEMS & COMPUTATION 1. What are Complex Systems? • Decentralization • Emergence • Self-organization 3 1. What are Complex Systems? Complex systems can be found everywhere around us a) decentralization: the system is made of myriads of "simple" agents (local information, local rules, local interactions) b) emergence: function is a bottom-up collective effect of the agents (asynchrony, homeostasis, combinatorial creativity) c) self-organization: the system operates and changes on its own (autonomy,
    [Show full text]
  • Machine Learning for Active Matter
    REVIEW ARTICLE https://doi.org/10.1038/s42256-020-0146-9 Machine learning for active matter Frank Cichos 1, Kristian Gustavsson 2, Bernhard Mehlig2 and Giovanni Volpe 2 The availability of large datasets has boosted the application of machine learning in many fields and is now starting to shape active-matter research as well. Machine learning techniques have already been successfully applied to active-matter data—for example, deep neural networks to analyse images and track objects, and recurrent nets and random forests to analyse time series. Yet machine learning can also help to disentangle the complexity of biological active matter, helping, for example, to establish a relation between genetic code and emergent bacterial behaviour, to find navigation strategies in complex environ- ments, and to map physical cues to animal behaviours. In this Review, we highlight the current state of the art in the applica- tion of machine learning to active matter and discuss opportunities and challenges that are emerging. We also emphasize how active matter and machine learning can work together for mutual benefit. he past decade has seen a significant increase in the amount their local environment to perform mechanical work7. Natural sys- of experimental data gathered in the natural sciences, as well tems, from molecular motors, to cells and bacteria, to fish, birds and Tas in the computer resources used to store and analyse these other organisms, are intrinsically out of thermodynamic equilib- data. Prompted by this development, data-driven machine-learning rium as they convert chemical energy. Their biochemical networks methods are beginning to be widely used in the natural sciences, and sensory systems are optimized by evolution to perform specific for example in condensed-matter physics1,2, microscopy3,4, fluid tasks: in the case of motile microorganisms, for example to cope mechanics5 and biology6.
    [Show full text]
  • The Environment Topography Alters the Transition from Single-Cell Populations to Multicellular Structures in Myxococcus Xanthus
    bioRxiv preprint doi: https://doi.org/10.1101/2021.01.27.428527; this version posted January 28, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-ND 4.0 International license. The environment topography alters the transition from single-cell populations to multicellular structures in Myxococcus xanthus Hernández Ramos, Karla C.1,2∞, Rodríguez-Sánchez, Edna2,3∞, Arias del Angel, Juan Antonio2, Arzola, Alejandro V.4, Benítez, Mariana2, Escalante, Ana E.2, Franci, Alessio5, Volpe, Giovanni6, Rivera-Yoshida, Natsuko2,5*. 1 Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico. 2 Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, CDMX, México 04510, Mexico. 3 Current address: Posgrado en Ciencias Biológicas, Instituto de Geología, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico. 4 Instituto de Física, Universidad Nacional Autónoma de México, Apdo Postal 20-364, 01000 Cd de México, Mexico. 5 Departamento de Matemáticas, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico. 6 Department of Physics, University of Gothenburg, Gothenburg, Sweden. ∞ Both authors equally contributed to this work * Corresponding author: [email protected], [email protected] ABSTRACT The social soil-dwelling bacteria Myxococcus xanthus can form multicellular structures, known as fruiting bodies. Experiments in homogeneous environments have shown that this process is affected by the physico-chemical properties of the substrate, but they have largely neglected the role of complex topographies.
    [Show full text]
  • The 2020 Motile Active Matter Roadmap
    The 2020 motile active matter roadmap Gerhard Gompper, Roland Winkler, Thomas Speck, Alexandre Solon, Cesare Nardini, Fernando Peruani, Hartmut Löwen, Ramin Golestanian, U Benjamin Kaupp, Luis Alvarez, et al. To cite this version: Gerhard Gompper, Roland Winkler, Thomas Speck, Alexandre Solon, Cesare Nardini, et al.. The 2020 motile active matter roadmap. Journal of Physics: Condensed Matter, IOP Publishing, 2020, 32 (19), pp.193001. 10.1088/1361-648X/ab6348. hal-02565758 HAL Id: hal-02565758 https://hal.archives-ouvertes.fr/hal-02565758 Submitted on 13 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. The 2019 Motile Active Matter Roadmap Gerhard Gompper1, Roland G. Winkler1, Thomas Speck2, Alexandre Solon3, Cesare Nardini4, Fernando Peruani5, Hartmut Löwen6, Ramin Golestanian7, U. Benjamin Kaupp8, Luis Alvarez8, Thomas Kiørboe9, Eric Lauga10, Wilson Poon11, Antonio De Simone12, Frank Cichos13, Alexander Fischer13, Santiago Muiños Landin13, Nicola Söker13, Raymond Kapral14, Pierre Gaspard15, Marisol Ripoll1, Francesc Sagues16, Julia Yeomans17, Amin Doostmohammadi17, Igor Aronson18, Clemens Bechinger19, Holger Stark20, Charlotte Hemelrijk21, Francois Nedelec22, Trinish Sarkar23, Thibault Aryaksama23, Mathilde Lacroix23, Guillaume Duclos23, Victor Yashunsky23, Pascal Silberzan23, Marino Arroyo24, Sohan Kale24 1. Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich 2.
    [Show full text]
  • Active Matter
    Active matter Collective Motion due to Quincke Rotation Tommy Fjelde Kristiansen Master of Science in Physics and Mathematics Submission date: July 2015 Supervisor: Jon Otto Fossum, IFY Co-supervisor: Paul Dommersnes, IFY Norwegian University of Science and Technology Department of Physics Active Matter: Collective motion due to Quincke rotation Tommy Fjelde Kristiansen June 2015 PROJECT / MASTER THESIS Department of Physics Norwegian University of Science and Technology Supervisor 1: Jon Otto Fossum Supervisor 2: Paul Dommersnes i Preface Master thesis in soft and complex matter at the institute of physics at NTNU as part of the study programme Physics and Mathematics. The thesis is in part based on prior experiments car- ried during the master project in autumn 2014, but the main work was done during the spring semester of 2015. The idea for this project was brought up by prof. Jon Otto Fossum and prof. II Paul Dommersnes when discussing a related project being undertaken by phD candidate Alexander Mikkelsen. It is assumed that the reader posses some understanding of electrody- namics, hydrodynamics and stability analysis, but while preferable it should hopefully not be strictly necessary. Trondheim, 2012-12-16 (Your signature) Tommy Fjelde Kristiansen ii Acknowledgment I would like to thank my supervisors prof. Jon Otto Fossum and prof. II Paul Gunnar Dommer- snes for their patience, guidance and sage advice provided over the course of my master thesis. A special thanks goes to Phd candidate Aleksander Mikkelsen, for providing logistical support, and more importantly, answering all the questions to embarrassing to ask the supervisors. I am grateful for the discussions we had with Dr.
    [Show full text]
  • Active Matter and Choreography at the Colloidal Scale Joseph
    Active Matter and Choreography at the Colloidal Scale Joseph Harder Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences COLUMBIA UNIVERSITY 2017 Copyright 2017 Joseph Harder All rights reserved ABSTRACT Active Matter and Choreography at the Colloidal Scale Joseph Harder In this thesis, I present numerical simulations that explore the applications of self-propelled particles to the field of self-assembly and to the design of `smart' mi- cromachines. Self-propelled particles, as conceived of here, are colloidal particles that take some energy from their surroundings and turn it into directed motion. These non-equilibrium particles can move persistently for long times in the same direction, a fact that makes the behavior of dense and semi-dilute systems of these particles very different from that of their passive counterparts. The first section of this thesis deals with the interactions between passive components and baths of hard, isotropic self-propelled particles. First, I present simulations showing how the depletion attrac- tion can be made into a short ranged repulsive, or long ranged attractive interaction for passive components with different geometries in a bath of self-propelled particles, and show how the form of these interactions is consistent with how active particles move near fixed walls. In the next chapter, a rigid filament acts as a flexible wall that engages in a feedback loop with an active bath to undergo repeated folding and unfolding events, behavior which would not occur for a filament in a passive environment. The subsequent chapters deal with self-propelled particles that have long ranged and anisotropic interactions.
    [Show full text]
  • Phoretic Active Matter and Micromachines
    PRACEdays18, European HPC Summit Week University of Ljubljana, 29-31 April 2018 Phoretic active matter and micromachines Marisol Ripoll, Forschungszentrum Jülich, Germany Ljubljana, 31/05/2018 Active matter : collective behavior Bacteria colony School of fish Mammalian herd Flock of birds Active matter : systems Biological Synthetic Wang, Duan, Ahmed, Mallouk, Sen, Nano Today (2013) 8, 531 Micromachines: Precise control at micro-nano scales Science fiction already thought about it Fantastic Voyage (1966) Doctor Who (2014) True science is still working on it … Di Leonardo et al., PNAS (2010) 107, 9541 Weinert and Braun, PRL (2008) 101, 168301 Challenges: Active matter and micromachines • Unravelling underlying mechanisms • Precise control at micro-nanoscale: microfluidics, microsurgery, drug delivery • Materials with novel properties • Harvesting of waste energy / refrigeration Phoresis = ‘migration’ (Physics) particle drift due to a solvent gradient • Electrophoresis • Magnetophoresis • Diffusiophoresis • Thermophoresis What do we mean by thermophoresis ? Thermophoresis of colloids Simulations of colloidal dispersions Solvent: Multiparticle collision dynamics (MPC, SRD) MPC: Explicit mesoscopic solvent Thermophoresis of colloids with MPC: MD Lüsebrink, Yang, Ripoll, J. Phys: Cond. Mat. (2017) 24, 284132 Flow field by a drifting phoretic colloid Thermophoretically active particles Phoretic active colloid: propelled velocity Phoretic active colloid: hydrodynamics Large ensemble simulations : HPC Besides the swimmer, a huge amount of solvent
    [Show full text]
  • And Morphogenetic Engineering: New Avenues Toward Self-Organized Architecture
    VUB AI-Lab / ULB IRIDIA, Winter 2012 “Current Trends in Artificial Intelligence” Course Series Fall 2011 Complex Systems, Bio-Inspiration and Morphogenetic Engineering: New Avenues Toward Self-Organized Architecture René Doursat Research Group in Biomimetics, Universidad de Malaga, Spain Complex Systems Institute Paris, CNRS / CREA, Ecole Polytechnique Project “GroCyPhy”: Growing Cyber-Physical Systems (S. Stepney, J. Miller et al., York) Artist’s impression of a garden of fully grown, growing, and pruned skyscrapers “Skyscraper Garden” © David A. Hardy/www.astroart.org 2012 SYMBRION: Symbiotic Evolutionary Robot Organisms (S. Kernbach, T. Schmickl, A. Winfield et al.) SWARMORPH: Morphogenesis with Self-Assembling Robots (M. Dorigo, R. O’Grady et al., IRIDIA, ULB) ARCHITECTURE & SELF-ORGANIZATION biological development, insect construction... ... robotic swarms, distributed software planned actitivities: civil engineering, mechanical engineering, collective motion, swarm intelligence, pattern formation, electrical engineering, computer engineering, companies, complex (social) networks, spatial communities (building) architecture, enterprise architecture, urbanism ARCHITECTURE & SELF-ORGANIZATION 1. What are Complex Systems? • Decentralization • Emergence • Self-organization 1. What are Complex Systems? Any ideas? The School of Rock (2003) Jack Black, Paramount Pictures 1. What are Complex Systems? A simplified classification of complex systems Agents / Emergent A "Complex Category Local Rules Parts Behavior System"? few simple “simple” few simple complex many simple “simple” many simple “complex” many complicated complex deterministic/ complicated many centralized 1. What are Complex Systems? Few agents, “simple” emergent behavior → ex: two-body problem fully solvable and regular trajectories for inverse-square force laws (e.g., gravitational or electrostatic) Two bodies with similar mass Two bodies with different mass Wikimedia Commons Wikimedia Commons 1.
    [Show full text]
  • Collective Motion Patterns Occurring in a Highly a Balanced Account of the Various Experimental and Diverse Selection of Biological Systems
    Collective motion Tam´as Vicsek1,2 & Anna Zafeiris1,3 1 Department of Biological Physics, E¨otv¨os University - P´azm´any P´eter stny. 1A, Budapest, Hungary H-1117 2 Statistical and Biological Physics Research Group of HAS - P´azm´any P´eter stny. 1A, Budapest, Hungary H-1117 3 Department of Mathematics, National University of Athens - Panepistimioupolis 15784 Athens, Greece Abstract We review the observations and the basic laws describing the essential aspects of collective motion – being one of the most common and spectacular manifestation of coordinated behavior. Our aim is to provide a balanced discussion of the various facets of this highly multidisciplinary field, including experiments, mathematical methods and models for simulations, so that readers with a variety of background could get both the basics and a broader, more detailed picture of the field. The observations we report on include systems consisting of units ranging from macromolecules through metallic rods and robots to groups of animals and people. Some emphasis is put on models that are simple and realistic enough to reproduce the numerous related observations and are useful for developing concepts for a better understanding of the complexity of systems consisting of many simultaneously moving entities. As such, these models allow the establishing of a few fundamental principles of flocking. In particular, it is demonstrated, that in spite of considerable differences, a number of deep analogies exist between equilibrium statistical physics systems and those made of self-propelled (in most cases living) units. In both cases only a few well defined macroscopic/collective states occur and the transitions between these states follow a similar scenario, involving discontinuity and algebraic divergences.
    [Show full text]
  • Structural Transition in the Collective Behavior of Cognitive Agents Received: 4 June 2019 Hannes Hornischer1,2, Stephan Herminghaus2 & Marco G
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE www.nature.com/scientificreportsprovided by Loughborough University Institutional Repository OPEN Structural transition in the collective behavior of cognitive agents Received: 4 June 2019 Hannes Hornischer1,2, Stephan Herminghaus2 & Marco G. Mazza 2,3 Accepted: 9 August 2019 Living organisms process information to interact and adapt to their surroundings with the goal Published: xx xx xxxx of fnding food, mating, or averting hazards. The structure of their environment has profound repercussions through both selecting their internal architecture and also inducing adaptive responses to environmental cues and stimuli. Adaptive collective behavior underpinned by specialized optimization strategies is ubiquitous in the natural world. We develop a minimal model of agents that explore their environment by means of sampling trajectories. The spatial information stored in the sampling trajectories is our minimal defnition of a cognitive map. We fnd that, as cognitive agents build and update their internal, cognitive representation of the causal structure of their environment, complex patterns emerge in the system, where the onset of pattern formation relates to the spatial overlap of cognitive maps. Exchange of information among the agents leads to an order-disorder transition. As a result of the spontaneous breaking of translational symmetry, a Goldstone mode emerges, which points at a collective mechanism of information transfer among cognitive organisms. These fndings may be generally applicable to the design of decentralized, artifcial-intelligence swarm systems. Te collective behavior of simple agents can exhibit a stunning degree of organization, as can be seen in the emer- gence of a mound from a cell colony of Dictyostelium discoideum, the construction of a complex termitarium by a termite colony, or the successful defense against predators by swarming starlings or a school of fsh.
    [Show full text]