Researchers have shown how energy disappears in quantum turbulence, paving the way for a better understanding of turbulence at scales ranging from microscopic to planetary.
Dr Samoli Oti of Lancaster University is one of the authors of a new study on quantum wave perturbation with researchers at Aalto University.
The team’s results are published in nature physicsAnd demonstrate a new understanding of how wave-like motion transfers energy from macroscopic to microscopic length scales, and their results confirm a theoretical prediction about how energy is dissipated at small scales.
“This discovery will become a cornerstone of the physics of large quantum systems,” said Dr. Otti.
Quantum turbulence is difficult to simulate at large scales – such as turbulence around moving aircraft or ships. On small scales, quantum turbulence differs from classical turbulence because the turbulent flow of quantum fluid is confined around line-like flow centers called eddies and can only take specific, specific values.
This granularity makes quantum disorder much easier to capture in theory, and it is generally believed that mastering quantum disorder will help physicists understand classical disorder as well.
In the future, an improved understanding of turbulence starting at the quantum level could allow for improved engineering in areas where the flow and behavior of liquids and gases such as water and air is a key question.
Lead author Dr Jerry Makinen from Aalto University said: “Our research with the building blocks of the disorder may help point the way to a better understanding of the interactions between different length measures in disorders.
“Understanding that in classical fluids will help us do things like improve the aerodynamics of vehicles, predict weather with better accuracy, or control the flow of water in pipes. There are a large number of potential real-world uses for understanding macroscopic turbulence.”
Dr. Oti said that quantum perturbation is a challenging problem for scientists.
In experiments, the formation of quantum perturbations around a single vortex has remained elusive for decades despite a whole field of physicists working on quantum perturbations trying to find it. This includes people working on superfluids and quantum gases such as the Bose-Einstein atomic condensate. (BEC) The theoretical mechanism behind this process is known as the Kelvin wave series.
“In the current manuscript we show that this mechanism exists and works as theoretically expected. This discovery will become a cornerstone of physics or large quantum systems.”
The team of researchers, led by senior scientist Vladimir Eltsov, studied turbulence in the helium-3 isotope in a unique ultra-low-temperature refrigerator at the Aalto Low-Temperature Laboratory. They found that on microscopic scales, so-called Kelvin waves act on the individual vortices by continually pushing energy into smaller and smaller scales – ultimately down to the range at which the energy dissipation occurs.
Dr Jerry Mäkinen from Aalto University said: “The question of how energy disappears from quantum vortices at extremely low temperatures has been crucial in the study of quantum turbulence. Our experimental setup is the first time that a theoretical model has transmitted Kelvin waves. Energy has been demonstrated to scale Dispersed length in the real world.
The team’s next challenge is to manipulate a single quantum vortex using nanoscale devices immersed in superfluids.
