Related Experiment Video
Updated: May 18, 2026
08:04
Controlling Flow Speeds of Microtubule-Based 3D Active Fluids Using Temperature
Published on: November 26, 2019
Collective dynamics of self-propelled particles with variable speed.
Shradha Mishra1, Kolbjørn Tunstrøm, Iain D Couzin
1Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 26, 2012
Summary
This study models collective motion in biological systems using self-propelled particles with variable speed. A novel power-law speed dependency reveals inverse correlations between speed, polarization, and density, and uncovers a phase-segregated regime.
Area of Science:
- Physics
- Biophysics
- Complex Systems
Background:
- Collective motion in biological systems, such as fish schooling, is complex.
- Understanding the factors influencing coordinated movement is crucial.
Purpose of the Study:
- To investigate a minimal model of self-propelled particles with variable speed.
- To explore the impact of speed-polarization feedback on collective motion dynamics.
Main Methods:
- Analytical derivation of a coarse-grained continuous approximation.
- Numerical simulations to verify analytical findings and explore beyond.
Main Results:
- Variable speed rules do not alter the collective motion ordering transition.
- An inverse power-law correlation emerges between speed/polarization and local density.
- A novel phase-segregated regime with static clusters and isolated fast particles is discovered near the transition.
Conclusions:
- The introduced variable speed mechanism influences correlations with density but not the ordering transition itself.
- The discovered phase segregation offers insights into disordered states in collective motion.
- The proposed mechanism may be broadly applicable to various collective dynamics.
More Related Videos
Related Concept Videos
01:20Principle of Linear Impulse and Momentum for a Single Particle
Linear momentum is a fundamental concept in physics that describes the motion of an object. It is a vector quantity, having a magnitude equal to the product of its mass and its velocity, and direction along the object's velocity. On the other hand, linear impulse, also known as momentum impulse, is a concept in physics related to the change in the linear momentum of an object. Impulse is a vector quantity defined as the product of force and the time over which the force is applied.
Delving into...
Delving into...
01:23Principle of Linear Impulse and Momentum for a Single Particle: Problem Solving
Consider a wooden box and a cylinder of known masses m1 and m2, respectively, hanging from a ceiling with the help of a massless pulley system.
01:21Principle of Linear Impulse and Momentum for a System of Particles
In the context of a system of particles moving relative to an inertial frame of reference, the equation of motion is a crucial tool for understanding the dynamics of the system. This equation, which accounts for external forces acting on each particle, plays a fundamental role in describing the system's behavior.
Notably, internal forces between particles, occurring in equal and opposite collinear pairs, cancel out and are not part of the equation of motion. This exclusion simplifies the...
Notably, internal forces between particles, occurring in equal and opposite collinear pairs, cancel out and are not part of the equation of motion. This exclusion simplifies the...
00:51Velocity and Acceleration of a Wave
A wave propagates through a medium with a constant speed, known as a wave velocity. It is different from the speed of the particles of the medium, which is not constant. In addition, the velocity of the medium is perpendicular to the velocity of the wave. The variable speed of the particles of the medium implies that there must be acceleration associated with it.
The velocity of the particles can be obtained by taking the partial derivative of the position equation with respect to time. We can...
The velocity of the particles can be obtained by taking the partial derivative of the position equation with respect to time. We can...
01:27Distribution of Molecular Speeds
The motion of molecules in a gas is random in magnitude and direction for individual molecules, but a gas of many molecules has a predictable distribution of molecular speeds. This predictable distribution of molecular speeds is known as the Maxwell-Boltzmann distribution. The distribution of molecular speeds in liquids is comparable to that of gases but not identical and can help to understand the phenomenon of the boiling and vapor pressure of a liquid. Consider that a molecule requires a...
01:20Stokes' Law
Viscous forces, like friction, are intermolecular forces that resist the relative motion of molecules over each other. When a solid body moves through a liquid, viscous forces drag it in the opposite direction. The force's magnitude depends on the solid's shape and size, as well as its speed and the liquid's coefficient of viscosity, density and temperature.
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...