The key difference between superfluidity and superconductivity is that superfluidity is the flow of helium 4 atoms in a liquid whereas superconductivity is the flow of an electron charge inside a solid.
The terms superfluidity and superconductivity are related phenomena of flow without resistance, but they describe these flows for different systems.
CONTENTS
1. Overview and Key Difference
2. What is Superfluidity
3. What is Superconductivity
4. Superfluidity vs Superconductivity in Tabular Form
5. Summary – Superfluidity vs Superconductivity
What is Superfluidity?
Superfluidity is a characteristic property of a fluid that has zero viscosity and able to flow without any loss of kinetic energy. If we stir a superfluid, it tends to form vortices that continue to rotate indefinitely. We can observe superfluidity occurring in two isotopes of helium: helium-3 and helium-4. We can liquify these two isotopes by cooling them to cryogenic temperature.
Superfluidity is a property of various other exotic states of matter that come under astrophysics, high energy physics, and quantum gravity. The theory regarding superfluidity was developed by Soviet physicist Lev Landau along with Isaak Khalatnikov. However, this phenomenon was originally discovered by Pyotr Kapitsa and John F. Allen in liquid helium.
Figure 01: Liquid Helium is Superfluidity
When considering the liquid helium-4, its superfluidity occurs at a very high temperature compared to that of helium-3. This is mainly because a helium-4 atom is a boson particle, by virtue of its integer spin while a helium-3 atom is a fermion particle that can form bosons only through pairing with itself at a low temperature. Moreover, the superfluidity of helium-3 was the basis for the Noble prize in physics in 1996.
What is Superconductivity?
Superconductivity is a quantum phenomenon where certain materials exhibit a high conductivity at particular magnetic and temperature regimes. This phenomenon was discovered by Onnes in 1911. However, there was no consistent microscopic theory that could describe why superconductivity occurs at the time of discovery. However, Bardeen and Cooper released a paper stating the mathematical foundation for conventional superconductivity.
The discovery of superconductivity happened during the study of transport properties of mercury (Hg) at low temperature. Onnes discovered that, below the liquifying temperature of the helium, (at about 4.2 K), the resistivity of mercury suddenly drops to zero. But the expectation was that the resistivity would either go to zero or diverge at a zero temperature but not vanish suddenly at a finite temperature. This vanishing indicated a new ground state and was discovered as a property of superconductivity.
What is the Difference Between Superfluidity and Superconductivity?
Superfluidity is a characteristic property of a fluid having zero viscosity and able to flow without any loss of kinetic energy. Superconductivity is a quantum phenomenon where certain materials exhibit a high conductivity at particular magnetic and temperature regimes. The key difference between superfluidity and superconductivity is that superfluidity is the flow of helium 4 atoms in a liquid whereas superconductivity is the flow of electron charge inside a solid.
The following infographic explores the difference between superfluidity and superconductivity in tabular form.
Summary – Superfluidity vs Superconductivity
Superfluidity is a characteristic property of a fluid having zero viscosity and able to flow without any loss of kinetic energy. Superconductivity is a quantum phenomenon where certain materials exhibit a high conductivity at particular magnetic and temperature regimes. The key difference between superfluidity and superconductivity is that superfluidity is the flow of helium 4 atoms in a liquid whereas superconductivity is the flow of electron charge inside a solid.
Reference:
1. “Superfluidity.” Wikipedia, Wikimedia Foundation, 7 May 2021.
Image Courtesy:
1. “Liquid helium Rollin film” By I, AlfredLeitner, took this photograph as part of my movie
“Liquid Helium, Superfluid” – Own work (Public Domain) via Commons Wikimedia