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

An EPiQS Pursuit: Physicist Andrea Young is chosen to receive an Experimental Investigator award from the Moore Foundation May 28th, 2020

Study finds electrical fields can throw a curveball: Particle-scale phenomenon akin to the swerving of a curveball could allow selective separation of suspended nanomaterials May 26th, 2020

Surrey reveals its implantable biosensor that operates without batteries May 22nd, 2020

Physics

An EPiQS Pursuit: Physicist Andrea Young is chosen to receive an Experimental Investigator award from the Moore Foundation May 28th, 2020

MSU scientists solve half-century-old magnesium dimer mystery May 22nd, 2020

Scientists break the link between a quantum material's spin and orbital states: The advance opens a path toward a new generation of logic and memory devices based on orbitronics that could be 10,000 times faster than today's May 15th, 2020

Wiring the quantum computer of the future: A novel simple build with existing technology: The basic units of a quantum computer can be rearranged in 2D to solve typical design and operation challenges April 24th, 2020

Superconductivity

Scientists use light to accelerate supercurrents, access forbidden light, quantum world May 21st, 2020

Electrons break rotational symmetry in exotic low-temp superconductor: Scientists previously observed this peculiar behavior in other materials whose ability to conduct electricity without energy loss cannot be explained by standard theoretical frameworks May 19th, 2020

Possible Futures

An EPiQS Pursuit: Physicist Andrea Young is chosen to receive an Experimental Investigator award from the Moore Foundation May 28th, 2020

Study finds electrical fields can throw a curveball: Particle-scale phenomenon akin to the swerving of a curveball could allow selective separation of suspended nanomaterials May 26th, 2020

Visualization of functional components to characterize optimal composite electrodes May 22nd, 2020

Researchers demonstrate transport of mechanical energy, even through damaged pathways: Topological pump can provide stability for communication technologies May 22nd, 2020

Chip Technology

A stitch in time: How a quantum physicist invented new code from old tricks: Error suppression opens pathway to universal quantum computing May 22nd, 2020

Oriented hexagonal boron nitride foster new type of information carrier May 22nd, 2020

Observation of intervalley transitions can boost valleytronic science and technology: UC Riverside-led research shows these transitions can emit light May 15th, 2020

Scientists break the link between a quantum material's spin and orbital states: The advance opens a path toward a new generation of logic and memory devices based on orbitronics that could be 10,000 times faster than today's May 15th, 2020

Discoveries

Study finds electrical fields can throw a curveball: Particle-scale phenomenon akin to the swerving of a curveball could allow selective separation of suspended nanomaterials May 26th, 2020

MSU scientists solve half-century-old magnesium dimer mystery May 22nd, 2020

Researchers review advances in 3D printing of high-entropy alloys: SUTD collaborates with universities in Singapore and China to shine light on HEA manufacturing processes and inspire further research in this emerging field May 22nd, 2020

A stitch in time: How a quantum physicist invented new code from old tricks: Error suppression opens pathway to universal quantum computing May 22nd, 2020

Announcements

An EPiQS Pursuit: Physicist Andrea Young is chosen to receive an Experimental Investigator award from the Moore Foundation May 28th, 2020

Study finds electrical fields can throw a curveball: Particle-scale phenomenon akin to the swerving of a curveball could allow selective separation of suspended nanomaterials May 26th, 2020

Visualization of functional components to characterize optimal composite electrodes May 22nd, 2020

Researchers demonstrate transport of mechanical energy, even through damaged pathways: Topological pump can provide stability for communication technologies May 22nd, 2020

Aerospace/Space

Study finds electrical fields can throw a curveball: Particle-scale phenomenon akin to the swerving of a curveball could allow selective separation of suspended nanomaterials May 26th, 2020

Sustainable structural material for plastic substitute May 11th, 2020

National Space Society Supports NASA's New Lunar Lander Decision: Strong Letter of Agreement Supports NASA Administrator's Announcement of Commercial Contracts May 6th, 2020

Wiring the quantum computer of the future: A novel simple build with existing technology: The basic units of a quantum computer can be rearranged in 2D to solve typical design and operation challenges April 24th, 2020

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

An EPiQS Pursuit: Physicist Andrea Young is chosen to receive an Experimental Investigator award from the Moore Foundation May 28th, 2020

Electrons break rotational symmetry in exotic low-temp superconductor: Scientists previously observed this peculiar behavior in other materials whose ability to conduct electricity without energy loss cannot be explained by standard theoretical frameworks May 19th, 2020

2D sandwich sees molecules with clarity: Rice University engineers adapt 2D ‘sandwich’ for surface-enhanced Raman spectroscopy May 15th, 2020

Water-splitting module a source of perpetual energy: ‘Artificial leaf’ concept inspires Rice University research into solar-powered fuel production May 4th, 2020

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