Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Atomic Nuclei: Nuclear Relaxation Processes01:23

Atomic Nuclei: Nuclear Relaxation Processes

925
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis,  the precessing magnetic moments are randomly oriented around the z-axis.
925
Ferromagnetism01:31

Ferromagnetism

2.8K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.8K
Atomic Nuclei: Nuclear Spin State Population Distribution01:14

Atomic Nuclei: Nuclear Spin State Population Distribution

1.6K
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
1.6K
Valence Bond Theory02:42

Valence Bond Theory

10.3K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
10.3K
Atomic Nuclei: Nuclear Spin State Overview01:03

Atomic Nuclei: Nuclear Spin State Overview

1.5K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
1.5K
First Law: Particles in Two-dimensional Equilibrium01:18

First Law: Particles in Two-dimensional Equilibrium

12.2K
Recall that a particle in equilibrium is one for which the external forces are balanced. Static equilibrium involves objects at rest, and dynamic equilibrium involves objects in motion without acceleration; but it is important to remember that these conditions are relative. For instance, an object may be at rest when viewed from one frame of reference, but that same object would appear to be in motion when viewed by someone moving at a constant velocity.
Newton's first law tells us about...
12.2K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Study of cephalic index of first-phase medical students of Rajendra Institute of Medical Sciences, Ranchi, Jharkhand.

Journal of family medicine and primary care·2026
Same author

Competing effect of disorder on phase separation in active systems.

Physical review. E·2026
Same author

AI awareness and the breakdown of daily recovery: a spillover pathway to work-family strain.

Frontiers in public health·2026
Same author

Hydrodynamic Bend Instability of Motile Particles on a Substrate.

Physical review letters·2026
Same author

Spontaneous rotation of an inclusion in a chiral active bath.

Soft matter·2025
Same author

Coarsening kinetics in active model B+: Macroscale and microscale phase separation.

Physical review. E·2025

Related Experiment Video

Updated: Nov 25, 2025

Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials
10:35

Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials

Published on: September 26, 2014

12.5K

Active nematics with quenched disorder.

Sameer Kumar1, Shradha Mishra1

  • 1Indian Institute of Technology (BHU), Varanasi, Uttar Pradesh 221005, India.

Physical Review. E
|December 17, 2020
PubMed
Summary
This summary is machine-generated.

We studied two-dimensional active nematics with quenched disorder. Disorder causes a crossover from quasi-long-range to short-range order by pinning topological defects, slowing dynamics and affecting scaling.

More Related Videos

Forming, Confining, and Observing Microtubule-Based Active Nematics
08:37

Forming, Confining, and Observing Microtubule-Based Active Nematics

Published on: January 13, 2023

3.0K
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
08:55

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Published on: June 7, 2018

8.8K

Related Experiment Videos

Last Updated: Nov 25, 2025

Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials
10:35

Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials

Published on: September 26, 2014

12.5K
Forming, Confining, and Observing Microtubule-Based Active Nematics
08:37

Forming, Confining, and Observing Microtubule-Based Active Nematics

Published on: January 13, 2023

3.0K
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
08:55

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Published on: June 7, 2018

8.8K

Area of Science:

  • Physics
  • Soft Matter Physics
  • Non-equilibrium Systems

Background:

  • Active nematics are dynamic systems with orientational order.
  • Quenched disorder introduces randomness that can significantly alter system behavior.
  • Understanding defect dynamics is crucial for active matter systems.

Purpose of the Study:

  • To investigate the impact of quenched disorder on a two-dimensional active nematic system.
  • To analyze the changes in order, dynamics, and correlation functions under varying disorder strengths.
  • To explore potential applications in living and artificial systems.

Main Methods:

  • Developed coarse-grained hydrodynamic equations for density and orientation.
  • Numerically solved the equations of motion.
  • Calculated two-point orientation correlation functions using linear approximation.

Main Results:

  • Observed a disorder-dependent crossover from quasi-long-range to short-range order.
  • Identified pinning of ±1/2 topological defects as the cause for domain breaking.
  • Found that finite disorder slows defect dynamics and growth, impacting correlation function scaling.

Conclusions:

  • Quenched disorder fundamentally alters the ordering and dynamics of 2D active nematics.
  • The system exhibits dynamic scaling but not static scaling under disorder.
  • Findings provide a basis for experimental verification and suggest applications in disordered active matter.