Related Experiment Video
Updated: Jan 22, 2026
13:02
Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow
Published on: February 27, 2016
12.9K
Evolution of large-scale flow from turbulence in a two-dimensional superfluid
Shaun P Johnstone1, Andrew J Groszek2, Philip T Starkey2
1School of Physics and Astronomy, Monash University, Victoria 3800, Australia. shaun.johnstone@monash.edu kristian.helmerson@monash.edu.
Science (New York, N.Y.)
|June 29, 2019
Summary
Researchers experimentally confirmed Lars Onsager's statistical hydrodynamic model by observing an inverse energy cascade in superfluid Bose-Einstein condensates. This study reveals emergent large-scale structures and negative absolute temperatures in nonequilibrium quantum systems.
Area of Science:
- Quantum hydrodynamics
- Statistical mechanics
- Condensed matter physics
Background:
- Nonequilibrium interacting systems can form large-scale structures.
- Two-dimensional turbulent flow exhibits persistent large-scale vortices.
- Lars Onsager proposed a statistical hydrodynamic model for quantized vortices.
Purpose of the Study:
- Experimentally confirm Onsager's statistical hydrodynamic model.
- Investigate emergent structures in nonequilibrium quantum systems.
- Explore inverse energy cascades and negative absolute temperatures.
Main Methods:
- Generated nonequilibrium vortex distributions in an oblate superfluid Bose-Einstein condensate by dragging a grid barrier.
- Observed signatures of an inverse energy cascade.
- Measured steady-state configurations.
Main Results:
- Experimental confirmation of Onsager's model.
- Observed an inverse energy cascade driven by vortex evaporative heating.
- Achieved steady-state configurations with negative absolute temperatures.
Conclusions:
- The study provides experimental evidence for Onsager's model in superfluid Bose-Einstein condensates.
- Demonstrated emergent large-scale structures in a quantum system driven far from equilibrium.
- Opened a pathway for quantitative studies of nonequilibrium quantum phenomena.
Related Concept Videos
01:24Turbulent Flow
686
Turbulent flow is characterized by unpredictable fluctuations in velocity and pressure, which result in a chaotic fluid movement distinct from the orderly patterns of laminar flow. While laminar flow is governed by smooth, parallel layers with minimal mixing, turbulent flow exhibits highly irregular, three-dimensional patterns. This behavior arises due to instabilities in the fluid's velocity profile, and amplifies as the flow velocity increases. Minor disturbances, known as turbulent...
686
01:07Laminar and Turbulent Flow
10.8K
Fluid dynamics is the study of fluids in motion. Velocity vectors are often used to illustrate fluid motion in applications like meteorology. For example, wind—the fluid motion of air in the atmosphere—can be represented by vectors indicating the speed and direction of the wind at any given point on a map. Another method for representing fluid motion is a streamline. A streamline represents the path of a small volume of fluid as it flows. When the flow pattern changes with time, the...
10.8K
01:09Turbulent Flow: Problem Solving
397
Carbonation is a process used to dissolve carbon dioxide gas in a liquid, commonly used in the production of carbonated beverages. Achieving efficient carbonation requires careful control of temperature, pressure, and flow conditions. By adjusting these parameters, carbonation efficiency can be maximized, producing a higher concentration of CO2 in the liquid.
Temperature is a key factor in CO2 solubility. In this case, the CO2 gas and the liquid are cooled to 20°C. Lower temperatures enhance...
Temperature is a key factor in CO2 solubility. In this case, the CO2 gas and the liquid are cooled to 20°C. Lower temperatures enhance...
397
02:55The Evidence for Evolution
47.7K
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.
47.7K
01:54Convergent Evolution
31.5K
Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.
31.5K
01:24Eukaryotic Evolution
40.3K
The endosymbiont theory is the most widely accepted theory of eukaryotic evolution; however, its progression is still somewhat debated. According to the nucleus-first hypothesis, the ancestral prokaryote first evolved a membrane to enclose DNA and form the nucleus. Conversely, the mitochondria-first hypothesis suggests that the nucleus was formed after endosymbiosis of mitochondria.
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...
40.3K