Physicists Erkki Thuneberg and Timo Virtanen of the University of Oulu have discovered that pendulums immersed in a quantum fluid speed up their movement rather than slow down.
How substances react to high temperatures is well-known. For example, atoms that are heated to extraordinary temperatures become ionic plasmas which respond to electromagnetic fields. But what happens when atoms are cooled to just a few tens of degrees Kelvin above absolute zero? The answer is superconductivity.
Superconductivity occurs when the temperature of a substance is cooled past a critical point and its electrical resistance is greatly reduced. As a consequence, other matter passing through this substance experiences very little resistance and can move more freely.
Ever since its discovery in 1911, physicists have been attempting to study superconductive properties. Thunberg and Virtanen joined these studies after hearing reports from researchers in Helsinki in the early 2000s claiming that pendulums sped up their movement when immersed in a mixture called Fermi liquid, which is a substance that has been cooled to a state that exhibits superconductivity.
Fermi Liquid is made of helium-3 atoms which are rare non-radioactive isotopes of helium with two protons and one neutron in its nucleus.
When in the Fermi liquid state, the particles within the atoms change into quasiparticles, which are characterized not only by particle type, based on its spin, charge and momentum, but also by how it affects the area around it. This is necessary because the way these particles interact with one another can change the nature of the system they inhabit.
What Thunberg and Virtanen discovered is that though these quasiparticles fly wildly throughout the liquid, they do no interact with each other as normal particles do.
Because the liquid is superconductive, the interaction between the particles produces minimal electrical resistance, which means that matter that moves through it — such as pendulums — will benefit from the particles’ movement rather than be hindered by it.
As a result, the pendulum will use the force exerted on it by the moving particles, without the hindrance of electrical resistance, and speed up its movement.
Thuneberg and Virtanen named this phenomenon the Landau force and hope to use it to discover more secrets within other quantum systems.
