[masteranza]

With all fairness don't you think this is not really time-crystal formation in the strict sense (those have been shown to be impossible), but rather an analogue to a "forced" crystal formation? I.e. the direct analogue would be setting up some spatially periodic potential and trapping some atoms in it then finding out it took every second spot. I admit that the doubling appears a bit mysterious from a condensed-matter point of view, but on the other hand period doubling is a well known phenomena in classical physics. I'm a physicist, though not working on time-crystals - some of my friends do.