This IS interesting, good find..!
So once again, a common theme seems to be that the experimental conditions focus energy onto electrons at small spatiotemporal scales, causing exotic quantum states. Note in section 5 tho it is suggested that the density / weight of the material is integral to this condensation effect, and would be precluded in eg. Cu foil.. on that point, note that Al is ~3x lower-density again.. Bob G. needs to obtain some heavier foils (and a dished emitter or else waveguide to provide a focal point, maybe)..!
