Entanglement and Spacetime


This research never ceases to amaze me, because it could be the meeting point between two totally incompatible theories; like general relativity and quantum mechanics. Following very recent theoretical research  it would appear that the entanglement mechanism (a purely quantum phenomenon valid for elementary particles) would be the basis of the geometry of spacetime itself, in turn described by the theory of general relativity. Entanglement would ensure that spacetime is a whole that is not detached from itself. So this is a problem of “quantum gravity” and not of simple quantum mechanics.

The test of these physicists was of an exclusively mathematical nature using the technique of “tensor networks” (obviously not experimental, which cannot be done for now) and was set up imagining what would happen if spacetime were entirely deprived of entanglement that binds him to itself: it would break into disjointed parts that would be stretched like  chewing gum. This is what mathematical modeling shows where formulas lead to geometric surfaces. What emerges is that, visualizing it for simplicity as a sphere depicting a model of the universe, spacetime within the sphere is conditioned by the entanglement on the surface of the sphere itself: in fact, it results that even when this spacetime universe is empty (without matter in the interior) the quantum fields on two points at will of that surface are in a state of entanglement between them.

From theoretical calculations it then emerges that if the entanglement between the two points is reduced this spacetime universe tends to split into two, while when the entanglement is brought to zero two separate universes are formed. This would demonstrate that the quantum entanglement mechanism is the main prerequisite for spacetime to exist. The fascinating aspect here, precisely where quantum physics and the theory of general relativity meet, is that this splitting into two separate universes corresponds exactly to what happens when a wormhole (spacetime tunnel) is formed through the so-called “Einstein-Rosen Bridge”.

At this point the two entry points between one universe and the other (born from a single spacetime universe) would be in a perfect state of entanglement between them. We would therefore have two connections, in the way that the quantum one generated by the entanglement and the relativistic one generated by the wormhole would be the exact same thing, even if in the case of the wormhole this would happen on a macroscopic scale.

Therefore here we have no entanglement between elementary particles (as it typically happens), but rather entanglement within spacetime. And therefore the entanglement would be the essential ingredient that holds together the spacetime itself, to the point that entanglement would work as a kind of “geometric glue” for spacetime. Conversely it does not take much to understand that if this theory is correct then two particles in a state of entanglement would be connected to each other by a wormhole in turn, since matter and spacetime are joined together by Einstein’s geometrodynamic theory. At this point the quantum entanglement mechanism would be the main basis supporting the reality in its entirety. All this seems to open up revolutionary doors towards a greater understanding of the Universe.

Reference Article published on Nature

Figure shows two Powerpoint slides from a recent lecture of mine.