A possible cause of the superfluidity of helium is two.

What is the viscosity of a certain liquid or gas from an atomic-molecular point of view?

It is quite obvious that atoms of monatomic gases or molecules of gases and liquids somehow “interlock” with each other.

At the expense of what?

Again, the only reasonable assumption is some kind of interaction (exchange) of their external electronic shells. This interaction has a twofold character: At very small distances, the interacting parts of their electronic shells begin to repel each other.

At a slightly greater distance from each other, the particles attract, and this is precisely due to the viscosity of liquids and gases.

At the time, I assumed that there are different viscosities: There is a certain Transverse viscosity, the usual Static, and a certain Longitudinal viscosity, Dynamic (or Kinematic), when certain currents arise in a gas or liquid, streams of moving particles. It is then that the second viscosity appears, Dynamic, Longitudinal, characterizing the adhesion of particles along the flow and it may be greater than the Static, Transverse viscosity.

Let us turn directly to the topic of the superfluidity of liquid helium two, discovered by P.L.Kapitsa in 1938, when liquid helium two flowed without the slightest adhesion through extremely narrow capillaries. Through which ORDINARY liquid helium could not flow at all due to a certain well-defined TRANSVERSE viscosity.

There are two experimental facts that “contradict” each other:

The first: This is the superfluidity of liquid helium two through capillaries whose diameter was one hundred thousandth of a centimeter or one tenth of a micron. The viscosity is zero!

Second: The viscosity of the same liquid helium two, measured by the time of attenuation of torsional vibrations of a disk immersed in helium two, turns out to be quite a “normal” NON-ZERO viscosity!

It would seem that in both cases, at a certain cryo-temperature, liquid helium two should exhibit superfluidity under ANY CONDITIONS, and not so strangely selectively!

This contradiction led me to the idea of two types of viscosity.

In the case of superfluidity of helium two through capillaries, this phenomenon can be easily explained by the fact that a monomolecular boundary layer is formed on the inner surface of any thinnest capillary, along which a stream of liquid helium two slides WITHOUT ANY internal friction (adhesion), without TRANSVERSE adhesion, but having a Dynamic, Longitudinal viscosity that LONGITUDINALLY binds the particles of the stream..

In the case of a disk, there is no Dynamic viscosity. There is only one Transverse viscosity, because there is no REAL MOVEMENT of the liquid, but only the movement of the solid surface of the lisk relative to the STATIONARY liquid helium two.

In 1940-1941, L.D. Landau described this phenomenon. It is like combining two helium atoms into pairs, and it is precisely because of this combination that fluidity arises.

Helium is known to be a monatomic gas.
Suppose that the outer electron orbits of helium atoms, in the case of their movement, are oriented along the flow and the Only Possible Coupling (exchange interaction) occurs their electronic orbits. There is no other possibility of their coupling! Then we have a kind of jet of atoms linked to each other, WHICH DO NOT HAVE any possibility of TRANSVERSE ADHESION. There is a superfluidity!

In the case of “standing” helium two, there is no flow of helium atoms and their possibility of exchange interaction with any other atoms remains free and chaotically suspended. Therefore, the boundary layer of helium stuck to the surface of the disk can adhere to the electrons of neighboring atoms open for exchange interaction and no superfluidity is observed in this experiment.

These are my assumptions.

Faciant meliora potentes.

28 VII 2024