Through Wave Collapse and the ensuing Entanglements it sometimes brings, QUANTUM PHYSICS CREATES A CAUSAL STRUCTURE, THROUGHOUT THE UNIVERSE, THUS, AN ARROW OF TIME.
Actually it’s more than a simple causal structure: it is an existential structure, as localization creates materialization, in the (Sub-)Quantum Theory I advocate. (It’s a theory where there are no dead-and-alive cats, but particles in flight are not particles… Contrarily to what Einstein thought, but more along the lines of Niels Bohr, horror of horrors…) It also means that time, at the smallest scale, is a nonlocal entanglement. This is not a weird new age poetry, but pretty much what the raw formalism of Quantum Physics say. I throw the challenge to any physicist to contradict this in any way. It’s completely obvious on the face of it.
You read it here first, as they say (although I may have said it before). Is time absolute? How could time be absolute? Where does the Arrow Of Time (Eddington) come from? Is there something else which grows with time?
The old answer is entropy, traditionally denoted by S.
Boltzmann’s equation S = k log P says that entropy augments during the evolution of a system. P indicates the number of states accessible by the system. Entropy was a construction from later Nineteenth Century physics, a successful attempt to understand the basic laws of thermodynamics (mostly due to Carnot).
A big problem for classical thermodynamics: what’s a state? That’s not clear.
However Quantum Physics define states, very precisely. However, very specifically: a situation, defined in space-time, what Bohr and Al. called an “experiment” (rightly so!) defines a number of possible outcomes: the latter become the “states”, a basis for the Hilbert Space the “experiment” defines.
Classical statistical mechanics does not enjoy such precisely defined states. So why not to use the states of Quantum Physics? Some could object that Quantum “experiments” are set-up by people. However Quantum Interactions happen all the time, independently of people. As in the Quantum experiments set-up by people, those Quantum Interactions grow something: Quantum Entanglement. ( Self-described “Quantum Mechanic” Seth Lloyd from MIT has also mentioned that entanglement and the arrow of time could be related.)
Quantum Entanglement has a direction: from where singularization (= localization = the collapse of the Quantum wave packet) happened first, to the distant place it creates the geometry of (yes, entanglement creates geometry, that’s why it’s so baffling to specialists!)

Quantum Physics, Or, More Precisely, What I call QUANTUM INTERACTIONS are irreversible processes. Hence the Arrow Of Time
So we have two things which grow, and can’t be reversed: Time and Wave Collapse/Quantum Entanglement. I propose to identify them. (After all, Maxwell proposed to identify electromagnetic waves and light, just because they are both waves and went at the same speed; it turned out to be a magnificent insight.)
Quantum Wave function collapse is time irreversible (actually, the entire Quantum Wave deployment is time irreversible, because it depends only upon the geometry it’s deployed in). The mechanism of wave function collapse is philosophically a matter of often obscure interpretations, and arguably the greatest problem in physics and philosophy.
My position here is perfectly coherent: I believe the Quantum Waves are real. (So I do not believe the waves are waves of ignorance, and an artefact, as some partisans of Quantum decoherence have it). Those objective waves are real, although not always in one piece (that’s how I generate Cold Dark Matter).
By the way, it is the collapse of the Quantum Wave which “creates” the Quantum Entanglement At least that’s how the mathematics, the description of the theory has it! The picture it creates in one’s mind (first the wave, then the collapse, then the entanglement) makes sense. Actually I am arguing that this is how sense makes sense!
Quantum Entanglement is a proven experimental fact. All physicists have to agree with that. Thus the Quantum Wave has to be real, as it is the cause of the Quantum Entanglement! (I am pointing out here that those, and that’s now nearly all of them, who believe in Entanglement are incoherent if they don’t believe in the wave too!).
Jules Henri Poincaré had seen that time and space were not equivalent. That was meritorious, as Poincaré had proposed the original ideas of “local time” and “local space” theories, which are the fundamental backbones of Special Relativity (they are deduced from the constancy of the speed of light).
Even Einstein publicly frowned on the concept of “spacetime”, which identifies space and time; “spacetime” was proposed by Minkowski, Einstein’s own professor at the EHT… They may not have been friends, as Minkowski compared Einstein to a “lazy dog”; Einstein, of course, respected Poincaré so much, that he grabbed the entire theory of Relativity from him, including its name…
Quantum Physics does not outright treat time as equivalent to space, quite the opposite (although Quantum Field theorists have tried to, and do treat space and “imaginary time” as the same!). In fundamental Quantum Physics, time is a one parameter group of transformation, not really a dimension.
When a glass falls and shatters, Classical Mechanics is at a loss:’Why can’t it reassemble itself, with as little work?” Classical Thermodynamics mumbles:’Because Entropy augments’. (That may be a tenable position, but one will have to count the states of the glass in a Quantum way. Even then, the full energy computation will reveal a lack of symmetry.)
I say, simply:’A glass which has shattered can’t be reassembled, because Quantum Interactions, and ensuing entanglements happen.’ The resulting topology of cause and effect is more complicated than what one started with, and can’t be reversed. Quantum Interactions and ensuing effects at a distance they provide with, create a partial, nonlocal, ordering of the universe. Time. (Once a set has been physically defined, it has been thoroughly interacted with, Quantum Mechanically, and then it becomes a “well ordering”!)
So what’s time? The causal structure of the universe as determined by irreversible, causal Quantum Wave collapse and Quantum Entanglement.
Patrice Ayme’