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

News and information

Bosch Sensortec launches ideation community to foster and accelerate innovative IoT applications : Creativity hub for customers, partners, developers and makers February 18th, 2019

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Tracking pollen with quantum dots: A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method February 17th, 2019

Super-light, super-insulating ceramic aerogel keeps the hottest temperatures at bay February 17th, 2019

Picosun’s ALD encapsulation prevents electronics degradation February 15th, 2019

Physics

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Superconductivity

Physicists uncover new competing state of matter in superconducting material January 4th, 2019

Revealing hidden spin: Unlocking new paths toward high-temperature superconductors: Berkeley Lab researchers uncover insights into superconductivity, leading potentially to more efficient power transmission January 4th, 2019

Oxford Instruments participates in the launch of the European Quantum Technology Flagship Programme ‘QMiCS’ December 13th, 2018

Physicists name and codify new field in nanotechnology: ‘electron quantum metamaterials:’ UC Riverside’s Nathaniel Gabor and colleague formulate a vision for the field in a perspective article November 5th, 2018

Possible Futures

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Tracking pollen with quantum dots: A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method February 17th, 2019

Super-light, super-insulating ceramic aerogel keeps the hottest temperatures at bay February 17th, 2019

Molecular Lego blocks: Chemical data mining boosts search for new organic semiconductors February 15th, 2019

Chip Technology

NRL, AFRL develop direct-write quantum calligraphy in monolayer semiconductors February 15th, 2019

Molecular Lego blocks: Chemical data mining boosts search for new organic semiconductors February 15th, 2019

Spintronics by 'straintronics': Switching superferromagnetism with electric-field induced strain February 15th, 2019

Picosun’s ALD encapsulation prevents electronics degradation February 15th, 2019

Discoveries

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Tracking pollen with quantum dots: A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method February 17th, 2019

The smallest skeletons in the marine world observed in 3D by synchrotron techniques February 15th, 2019

Researchers create ultra-lightweight ceramic material that withstands extreme temperatures: UCLA-led team develops highly durable aerogel that could ultimately be an upgrade for insulation on spacecraft February 15th, 2019

Announcements

Bosch Sensortec launches ideation community to foster and accelerate innovative IoT applications : Creativity hub for customers, partners, developers and makers February 18th, 2019

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Tracking pollen with quantum dots: A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method February 17th, 2019

Super-light, super-insulating ceramic aerogel keeps the hottest temperatures at bay February 17th, 2019

Aerospace/Space

Researchers create ultra-lightweight ceramic material that withstands extreme temperatures: UCLA-led team develops highly durable aerogel that could ultimately be an upgrade for insulation on spacecraft February 15th, 2019

Three CEA Projects Awarded European Research Council Synergy Grants November 26th, 2018

'Smart skin' simplifies spotting strain in structures: Rice U. invention can use fluorescing carbon nanotubes to reveal stress in aircraft, structures November 15th, 2018

Epoxy compound gets a graphene bump: Rice scientists combine graphene foam, epoxy into tough, conductive composite November 14th, 2018

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

Nominations invited for $250,000 Kabiller Prize — the world’s largest monetary award for achievement in nanomedicine: An additional $10,000 award will honor a young investigator in nanoscience, nanomedicine February 7th, 2019

Brilliant glow of paint-on semiconductors comes from ornate quantum physics January 18th, 2019

Scientists program proteins to pair exactly: Technique paves the way for the creation of protein nanomachines and for the engineering of new cell functions December 21st, 2018

Strem Chemicals, Inc., Receives National Performance Improvement Honor: Company Recognized for Stakeholder Communications December 20th, 2018

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