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Sunday, October 25, 2015

Time, Entropy & Entanglement (just a brief note)

A recent article posits that time is a side-effect of quantum entanglement ... a more thorough discussion of the same ideas seems to be here ...

Actually, this makes perfect sense ... since the directionality of time is often viewed as ensuing from entropy gradients ... why should some sort of time not emerge from "entanglement entropy" gradients ... the process of disentanglement provides an arrow of time...

However, if disentanglement is due to "measurement" which has to do with decoherence ... then, this sorta boils down to good old entropy once again, in a sense ... because measurement/decoherence has to do with coupling to a "macroscopic" observer, and the crux of being macroscopic is to be thermodynamically analyzable, i.e. to experience the Second Law...

So quantum measurement consists of coupling to a system that experiences an arrow of time (via being "macroscopic") -- and this coupling then causes disentanglement which gives the observed quantum system its own arrow of time, induced via the observing system's arrow of time...


Thermodynamic/informational entropy ensues from coarse-graining of a system's state-space.   A macroscopic system is, perhaps, one whose state space can meaningfully be coarse-grained....    Relative to such a coarse-graining, we can get decoherence, and thus entanglement-entropy-induced microscopic time-arrows....  

So the path to time begins with the decision to look at a system's set of states approximately -- which is a natural step for any observer with significantly limited resources...

Coarse-graining is basically another word for generalization -- it's to do with grouping similar states into categories, and then looking at these categories instead of the original sets.   Coarse graining and generalization are basic operations of intelligence.


Intelligence approximates state-spaces, as an intrinsic part of its nature; this (coupled with the intrinsic chaos in the universe) leads to entropy which leads to decoherence which leads to disentanglement, so we have macro and micro time arrows....

With infinite resources, we don't need intelligence, so we don't spawn time...

1 comment:

YYZ said...

Ben, I nearly mentioned this experiment in my comments on the CTMU post from Monday, October 19, 2015.

One of these articles here begins: "Time is an emergent phenomenon that is a side effect of quantum entanglement, say physicists. And they have the first experimental results to prove it." This seems conceptually quite similar to the CTMU's model where essentially time, space, & motion emerge from the unified multiplex (entanglement?) of the internalized parameters of operators in a closed system. While certainly there are vast differences between them, at least on the surface the similarity seems noteworthy.