Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

Home > Press > Superfluidity: what is it and why does it matter?

Illinois physics professor and Nobel Laureate Anthony Leggett talks about the 1938 discovery of superfluidity and its significance to low-temperature physics.

Photo by L. Brian Stauffer
Illinois physics professor and Nobel Laureate Anthony Leggett talks about the 1938 discovery of superfluidity and its significance to low-temperature physics. Photo by L. Brian Stauffer

Abstract:
2018 marks the 80th anniversary of the landmark physics discovery of superfluidity. News Bureau physical sciences editor Lois Yoksoulian asked University of Illinois physics professor and 2003 Nobel Prize winner Anthony Leggett about the significance of the historic finding.

Superfluidity: what is it and why does it matter?

Champaign, IL | Posted on December 20th, 2018

What is superfluidity?

The most obvious definition of superfluidity is the ability of a liquid to flow through narrow channels without apparent friction. However, this is actually only one of a number of interesting properties. For example, if we place a liquid into a bucket and slowly rotate it while cooled into the superfluid phase, the liquid, which initially rotates with the bucket, will appear to come to rest. We call this phenomenon the Hess-Fairbank effect.

Today, superfluidity is something that we can directly observe in helium isotopes and in ultra-cold atomic gases. It is conjectured to occur in extraterrestrial systems, such as neutron stars, and there is circumstantial evidence supporting its existence in other terrestrial systems, such as excitons, which are bound electron-hole pairs found in semiconductors.

How was superfluidity discovered?

Helium-4 was liquefied in 1908, but it was only in 1936 and 1937 that scientists recognized that below the temperature of 2.17 degrees absolute – which we now call the lambda point – it possessed properties different from any other substance known at the time. In particular, the thermal conductivity of the low-temperature phase, now known as He-II, is very large, which suggests a convection mechanism, but with anomalously low viscosity.

In 1938, Pyotr Kapitza in Moscow and John Allen and Don Misener at the University of Cambridge simultaneously performed a direct measurement of the behavior of the viscosity of the helium contained in a thin tube as a function of temperature. Both groups found a drop in He-II, which appeared discontinuously at the lambda point. On the basis of the analogy with superconductivity, Kapitza coined the term superfluidity for this behavior.

What is the relationship between superfluidity and superconductivity?

According to our modern understanding, superconductivity is nothing more than superfluidity occurring in an electrically charged system. Just as a superfluid liquid can flow forever down a narrow capillary without apparent friction, so can a current, once started in a superconducting ring – or at least for a time much longer than the age of the Universe!

The analog of the Hess-Fairbank effect mentioned earlier is a bit less intuitive. The direct analog is that when a magnetic field is applied to the surface of a metal, the normal, non-superconducting state has little effect. However, when the metal is in the superconducting state, it will induce an electric current, or diamagnetism. In a thin ring, this would be the end of the story, but in a bulk sample this current induces its own magnetic field in a direction opposite to the external one, and eventually the latter is screened out of the metal completely. This is the so-called Meissner effect, and leads to spectacular phenomena such as superconducting levitation.

What types of advancements have been made as a result of understanding superfluidity?

The direct uses of superfluid helium are actually rather few. Because of its extremely high thermal conductivity, the superfluid phase of helium-4 is an excellent coolant for high-field magnets, and both isotopes have some applications as detectors of exotic particles. While there are other unique indirect applications of superfluidity, they are most useful in the development of theory and understanding high-temperature superconductivity.

####

For more information, please click here

Contacts:
LOIS YOKSOULIAN
PHYSICAL SCIENCES EDITOR
217-244-2788


Anthony Leggett

Copyright © University of Illinois at Urbana-Champaign

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Physics

Appreciating the classical elegance of time crystals: Physicists at ETH Zurich have developed a versatile framework for studying periodically driven systems, providing a unifying platform to explore so-called 'time crystals' in both the classical and the quantum regime September 20th, 2019

In a quantum future, which starship destroys the other? Quantum physicists blur the lines of cause and effect, illustrating how a sequence of events can flip and co-exist at the same time August 23rd, 2019

Studying quantum phenomena in magnetic systems to understand exotic states of matter August 21st, 2019

Kavli Lectures: Innovation by evolution and harnessing the quantum mechanics of the hydrogen bond August 15th, 2019

News and information

Appreciating the classical elegance of time crystals: Physicists at ETH Zurich have developed a versatile framework for studying periodically driven systems, providing a unifying platform to explore so-called 'time crystals' in both the classical and the quantum regime September 20th, 2019

'Nanochains' could increase battery capacity, cut charging time September 20th, 2019

SMART announces a revolutionary tech to study cell nanomechanics: New research discovery enables scientists to study membrane mechanics of cell's nucleus, revolutionising the understanding of metastatic cancers as well as opening the doors for identification of stem cells for the September 20th, 2019

Nano bulb lights novel path: Rice University engineers create tunable, nanoscale, incandescent light source September 20th, 2019

Superconductivity

Scientists couple magnetization to superconductivity for quantum discoveries September 6th, 2019

Possible Futures

Appreciating the classical elegance of time crystals: Physicists at ETH Zurich have developed a versatile framework for studying periodically driven systems, providing a unifying platform to explore so-called 'time crystals' in both the classical and the quantum regime September 20th, 2019

'Nanochains' could increase battery capacity, cut charging time September 20th, 2019

SMART announces a revolutionary tech to study cell nanomechanics: New research discovery enables scientists to study membrane mechanics of cell's nucleus, revolutionising the understanding of metastatic cancers as well as opening the doors for identification of stem cells for the September 20th, 2019

Nano bulb lights novel path: Rice University engineers create tunable, nanoscale, incandescent light source September 20th, 2019

Chip Technology

Nano bulb lights novel path: Rice University engineers create tunable, nanoscale, incandescent light source September 20th, 2019

The future of materials with graphene nanotubes starts in Japan September 19th, 2019

Uncovering the hidden “noise” that can kill qubits: New detection tool could be used to make quantum computers robust against unwanted environmental disturbances September 17th, 2019

A Quantum Leap: $25M grant makes UC Santa Barbara home to the nation’s first NSF-funded Quantum Foundry, a center for development of materials for quantum information-based technologies September 16th, 2019

Discoveries

Appreciating the classical elegance of time crystals: Physicists at ETH Zurich have developed a versatile framework for studying periodically driven systems, providing a unifying platform to explore so-called 'time crystals' in both the classical and the quantum regime September 20th, 2019

'Nanochains' could increase battery capacity, cut charging time September 20th, 2019

Nano bulb lights novel path: Rice University engineers create tunable, nanoscale, incandescent light source September 20th, 2019

Tiny bubbles in our body could fight cancer better than chemo September 18th, 2019

Announcements

Appreciating the classical elegance of time crystals: Physicists at ETH Zurich have developed a versatile framework for studying periodically driven systems, providing a unifying platform to explore so-called 'time crystals' in both the classical and the quantum regime September 20th, 2019

'Nanochains' could increase battery capacity, cut charging time September 20th, 2019

SMART announces a revolutionary tech to study cell nanomechanics: New research discovery enables scientists to study membrane mechanics of cell's nucleus, revolutionising the understanding of metastatic cancers as well as opening the doors for identification of stem cells for the September 20th, 2019

Nano bulb lights novel path: Rice University engineers create tunable, nanoscale, incandescent light source September 20th, 2019

Aerospace/Space

The future of materials with graphene nanotubes starts in Japan September 19th, 2019

In a quantum future, which starship destroys the other? Quantum physicists blur the lines of cause and effect, illustrating how a sequence of events can flip and co-exist at the same time August 23rd, 2019

Study models new method to accelerate nanoparticles August 23rd, 2019

Better microring sensors for optical applications May 10th, 2019

Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records

'Nanochains' could increase battery capacity, cut charging time September 20th, 2019

One-atom switch supercharges fluorescent dyes: Rice University lab discovers simple technique to make biocompatible 'turn-on' dyes September 13th, 2019

Gem-like nanoparticles of precious metals shine as catalysts: Heated particles shift shape and become highly active catalytically September 12th, 2019

Hard as a diamond? Scientists predict new forms of superhard carbon: A study identifies dozens of new carbon structures that are expected to be superhard, including some that may be about as hard as diamonds September 9th, 2019

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project