The term "lower energy state" is a funny one, because isn't energy conserved? What's happening is a drop to a more spread out state, where you have several particles making great time flying away from each other instead of one high-energy-density locus in the center.
Edit: Just to clarify, the time-variant system exception does not apply in this case. It really is an entropy thing, moreso than an energy thing (which is constant in every particle decay that happens on Earth.)
The idea that spacetime itself has energy, which balances out the apparent lack of energy conservation in matter fields, is a far stronger interpretation than the article suggests. Spacetime energy bends spacetime, which is why gravitational waves exist. It's even called the stress-energy tensor.
This is lovely. Wikipedia sent me from energy not being conserved, to time translation symmetry breaking, to time crystals as a source of perpetual motion.
Just need to find a tie-in to 5G and I can write my own time-cube parody website.
(The article is also very interesting, of course!)
MengerSponge's article is raising an extremely subtle point about how we translate modern physical theories into English: we do it poorly.
Conservation laws (Noether's theorem) are dependent on the way the physics is voiced, mathematically. Saying "energy is conserved" is the moral equivalent of looking at Newton's laws and just ignoring GR. GR tells us new, precise, and amazing things about conservation laws. It's just that, unfortunately, they're a little hard to translate into English.
By Noether's theorem as long as you don't have the laws of Physics change over time then energy will be conserved. The problem is that the definition of energy changes when you model a different system or change the way you model an existing system (ie Newtonian -> GR). A follow up problem is that the energy definition that results from applying Noether's theorem can get hard to translate in plain English.
