This is just messing with us right? Star trek level technobabble?
Just kidding, seems an exciting result, even if it flies way over my head.
- Supersolid: it's a state of matter when a system is both organised like a solid but presents superfluid-like flow without viscosity.
- Driven-dissipative: it's a qualifier for systems which are dissipative (excitations of the systems dissipate energy as heat) and driven by external fields (in this case strong electromagnetic fields are keeping the supersolid in shape). In physics, "driven" usually refers to an external influx of energy or force kept on the system.
- non-equilibrium system is what we call systems where the physics cannot be fully described by a statistical analysis of the whole over long times. These systems have transitory behaviours which are often complex before they return to equilibrium (unless they are driven away from it).
Exciton-polariton: excitons and polaritons are what we call quasiparticles. They're not particles in the sense of an electron or photon, but instead they are excitations of the collective system which look like particles. Kind of like how waves on the ocean aren't one water molecule, but a bunch of them. An exciton has no charge (it's essentially an electron and a missing electron stuck together). When an exciton couples to electromagnetic waves (photons), it can make a special type of polariton (another quasiparticle) which we call an exciton-polariton.
- Photonic = made of photons
https://en.wikipedia.org/wiki/Electron_hole
but it's more like a way of describing a system.
Which also means that nobody is making a solid object from photons, it's all "behaves like a solid would if you look at our system a certain way". Right?
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Also - I don't see how the phrases "behaves like a solid" and "presents flow" can agree. Isn't the whole point of a solid that it _doesn't_ flow?
First, just like a superfluid, a supersolid can have a portion that flows and one that doesn't (the normal fraction).
The second part is that, as you rightfully mentioned, holes are just vacancies in the structure. Here the vacancies in the crystalline structure they made are able to flow along the solid. But as they flow, the structure retains its shape. And at low enough temperature, these excitations condense into a macroscopic quantum state which makes them a superfluid.
So in a nutshell, you have an organised structure like a solide, but a portion of that structure flows without breaking the overall structure.