The existence of so called supersolids was predicted long time ago by Russian theoreticians Andreev and Liftschitz, who proposed that 4He, which is a bosonic solid at low temperatures and as a noble element has weak bonds between atoms, could make under a high enough pressure a phase transition to a supersolid state which is the analog of super-fluid state. Supersolid can be regarded as a Bose-Einstein condensate behaving like single particle and having vanishing friction with respect to other solids.
What the loss of friction with respect to other solid means is not quite clear. The conservative view is that supersolid can glide along another solid without friction. A more radical view is that supersolid can flow through other solids, even ordinary, without any friction.
There is empirical support for the latter option. The experimental procedure used by M. Chan and his student E. Kim is roughly the following.
- Compress 4He gas into a small glass disk made of fused silica containing atomic-sized pores.
- Construct a torsional oscillator by hanging this disk to a string spinning with kHz frequency back and forth. Increase the pressure gradually from the solidification pressure 40 atm to 62 atm and monitor the oscillation frequency as the pressure is increased.
What is observed is a sudden increase of oscillation frequency at .2 K as if some of 4He had leaked out and the system would have lost some of its inertia. The experimenters have however excluded the leakage. Their explanation is in terms of the emergence of 4He supersolid phase which remains at rest since it has no friction: glass simply flows through it. The effect is absent for $^3$He, which is a fermionic solid, and this supports the conclusion of the experimentalists.
The ability to flow through another solid makes the notion of supersolid highly counterintuitive in ordinary single-sheeted space-time. Intuitively one tends to assign the friction with the boundary of the supersolid and solid rather than interior and this would mean that supersolid would only glide without friction along but not flow through another solid.
Quantum classical correspondence is the basic interpretational guideline of TGD and forces to ask what the space-time correlate for the formation of supersolid, or whatever is in question in the experiment, might be. The ability of the two solids to flow through each other can be understood if the formation of the supersolid involves the separation of supersolid phase to its own space-time sheet. This separation becomes possible if the friction between ordinary solid and supersolid vanishes. Obviously this interpretation is consistent with the conservative view and implies the radical view in many-sheeted space-time.
Large hbar supersolids could exist even at room temperature so that technological implications would be quite dramatic. Also the artifacts in wrong places could result by a temporary phase transition to large hbar supersolid phase. The low temperature of the phase transition suggests that 4He is not large hbar phase.
For more about interpretation of artifacts in wrong places as solid objects which have suffered temporary transformation to large hbar dark matter see the end of the chapter Quantum Coherent Dark Matter and Bio-Systems as Macroscopic Quantum Systems of "Genes, Memes, Qualia,...".