Quantum Entanglement Drives the Arrow of Time

Sure (as far as my layman's understanding of quantum physics goes).

So, you have independent physical system (say, a photon). Before it interacts it exists in quantum superposition. It has the potential to exist in any possible configuration and, in fact, seems to exist in all of them simultaneously. Almost like a variable of a certain type but this type is kind of special in that some possible values are more likely than others.

You can combine these 'probability types' systems with others and get useful information out of them in aggregate (example, wave interference patterns) very easily. They seem very well suited to treating them in aggregate in bulk calculations -- IOW, it is computationally cheaper to keep them in this state until the individual values of the variables must be extracted and used. Then the universe accesses the actual value of that individual variable that, so far, has only been needed as part of the aggregate if at all, through an interaction. Then, and only then, is the variable loaded with a concrete value chosen from its probability type through entanglement and it becomes useless as part of these aggregate calculations since it must be treated as an individual entity with a value.

(I am ignorant of quantum physics outside of pop science articles, so if I have something egregiously wrong, please let me know).

Let's say you've made a video game. It is a MMO set in the Stone Age based around massive battles with slings and swords. There are hundreds of thousands of players and computer controlled NPCs in the same world simultaneously. To conserve server resources many calculations are done on the client computer. The clients cannot be expected to do a full calculation for every projectile in the world so there is an algorithm that chooses to load state of only those players that are near enough to actually act on that particular client.

Let's say a player has come onto the battlefield out of range of everyone else but has a scrying spell that allows that player to see an overhead map showing dots of troop formations. This is the aggregate calculation. This player doesn't need to know every other player's full state, just their general density (because he only gets a dot for every ten or so players). As this player moves toward the battle, some NPC comes in range. Suddenly the player needs to know much more state so it is chosen from the possible values and now that NPC must act in a certain way -- only have certain state changes, because only certain transitions make sense now that he's been interacted with. The NPC can't go from fully armored with a spear to in a loin cloth with a sling, for example. And any NPCs in range of that NPC must also de-cohere into a fully defined state and so on. They all become entangled.

Does any of that make any sense whatsoever? I know these are imperfect analogies.

This implies that atoms behave like little billiard balls, but nearly a century of quantum physics has shown us very clearly that belief is false. Unless you are looking at it, atoms exist as their wave function (and recent experiments have shown that a collapse won't occur while you are watching so e.g. a radioactive isotope will not decay while being observed), so any description of behavior needs to use their wave function to describe it.

Isn't that exactly what the paper this article references is stating a proof of: that the reforming is physically impossible?

A lot of people in this thread are questioning how this adds any new information about time or how it is different/better than a classical explanation of systems (coffee cup reaching equilibrium based on thermodynamic laws).

One way that this result makes sense to me is by considering the properties of light speed and "spooky action at a distance." Particles become entangled with one another at the speed of light -- photons or fields carrying the information between the two. Looking at this from the perspective of light speed, there has been an instantaneous change between the two particles. State A has led directly to a more complicated, entangled State B. Still looking at this from light speed, there is no time between the transition from one state to the next and from that one to the next and so on. The universe has already worked itself out from the initial disentangled state to all the states that are increasingly more entangled.

Thanks to Einstein, we know that all objects try to move at light speed, but that the more massive they are the slower they become. Because we are massive objects, we don't experience time instantaneously like the photons do. We see the propagation of entanglement and see the state transitions. Our massiveness has given rise to a direction of time, the order that we understand the states of the universe to be proceeding in. Unlike light, we have to experience all the intermediate states in the order of less entangled -> more entangled. Thus an arrow of time.

This is already subtly bundled up in the classical explanations. Coffee cools off because it reaches equilibrium. Classical physics says this is because the particles in the coffee are hotter than the surrounding air, so it is more likely for those particles to break free of the coffee, thereby reducing its average kinetic motion. Consider though how those particles are interacting with one another. They don't just "know" the direction they're supposed to go, they bump into each other's fields and communicate at light speed. Each particle informs the next and as they become more entangled and learn more about where they are, they progress from state to state.

What does classically correlated mean? Is it different than quantum correlated? (Is this analogous to the difference between pure and mixed states?)