Something about the universe watching itself

I see that the currently dysfunctional Twitter is still getting some interesting tweets.  This one, for example:

The comments following included a link to this tweet:

The paper linked to there is new, and here is the (not easy to follow!) abstract:

We recently showed that if a massive (or charged) body is put in a quantum spatial superposition, the mere presence of a black hole in its vicinity will eventually decohere the superposition. In this paper we show that, more generally, decoherence of stationary superpositions will occur in any spacetime with a Killing horizon. This occurs because, in effect, the long-range field of the body is registered on the Killing horizon which, we show, necessitates a flux of "soft horizon gravitons/photons" through the horizon. The Killing horizon thereby harvests "which path" information of quantum superpositions and will decohere any quantum superposition in a finite time. It is particularly instructive to analyze the case of a uniformly accelerating body in a quantum superposition in flat spacetime. As we show, from the Rindler perspective the superposition is decohered by "soft gravitons/photons" that propagate through the Rindler horizon with negligible (Rindler) energy. We show that this decoherence effect is distinct from--and larger than--the decoherence resulting from the presence of Unruh radiation. We further show that from the inertial perspective, the decoherence is due to the radiation of high frequency (inertial) gravitons/photons to null infinity. (The notion of gravitons/photons that propagate through the Rindler horizon is the same notion as that of gravitons/photons that propagate to null infinity.) We also analyze the decoherence of a spatial superposition due to the presence of a cosmological horizon in de Sitter spacetime. We provide estimates of the decoherence time for such quantum superpositions in both the Rindler and cosmological cases.

The paper itself talks about the cosmological horizon being a Killing horizon:

The event horizon of a stationary black hole is a Killing horizon [ 16– 18 ], so spacetimes with Killing horizons encompass the case of stationary spacetimes that contain black holes.  However, there are many cases of interest where Killing horizons are present without the presence of black holes.  One such case is that of Minkowski spacetime, where the Rindler horizon is a Killing horizon with respect to the Lorentz boost Killing field. Another such case is de Sitter spacetime, where the cosmological horizon is a Killing horizon.

One of the other authors thus tweets:

His thread perhaps gives a more general explanation of the potential importance of the idea:

And here are another series of tweets trying to explain:

Of course, I can't tell how much merit or significance there is to this idea.  I would guess Sabine Hossenfelder will get to it on one of her videos soon.   

Update:  it just occurred to me - does this mean that proximity to a black hole has an effect on quantum experiments?   If one is passing through your solar system, does it matter to a lab experiment?