Research  Causal order doesn’t work, physicists find. Now what?

#1
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VIDEO INTRO: To us normal people, cause and effect are linked together in a distinct order. The cause occurs first, and the effect follows after. But according to a new paper, that causal order breaks down if you apply quantum mechanics to gravity. Join me in my quest to wrap my head around this head-spinning (but also plausible) paper. [The latter's abstract is in spoiler.]

ABSTRACT: We derive multiparty games that, if the winning chance exceeds a certain limit, prove the incompatibility of the parties' causal relations with any partial order. This, in turn, means that the parties exert a backaction on the causal relations; the causal relations are dynamical.

The games turn out to be representable by directed graphs, for instance by an orientation of the Möbius ladder. We discuss these games as device-independent tests of space-time's dynamical nature in general relativity.

To do so, we design relativistic settings where, in the Minkowski space-time, the winning chance is bound to the limits. In contrast, we find otherwise tame processes with classical control of causal order that win the games deterministically. These suggest a violation of the bounds in gravitational implementations.

We obtain these games by uncovering a “pairwise central symmetry” of the correlations in question. This symmetry allows us to recycle the facets of the acyclic subgraph polytope studied by Grötschel, Jünger, and Reinelt in the mid-80s for combinatorial optimization.

In addition, we derive multiparty games in a scenario where the polytope dimension grows only linearly in the number of parties. Here, exceeding the limits not only proves the dynamical nature of the causal relations, but also that the correlations are incompatible with any global causal order.

PAPER: Möbius games and other Bell tests for relativity ..... FREE: https://arxiv.org/abs/2309.15752

Causal Order Doesn’t Work, Physicists Find. Now what? ... https://youtu.be/C6c2R6VgGnc

https://www.youtube-nocookie.com/embed/C6c2R6VgGnc
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#2
Magical Realist Offline
So then either gravity is emergent or causality is emergent? Thinking now of another video of her's where time is also put into question. That would definitely be a stake in the heart of causality as well. I'm presently having my doubts about time as well, at least as an objectively physical phenomenon. What I prefer to call "the flow of Being" is what is fundamentally real and underlies everything. Something along the lines of Bergson's concept of "duration"..
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