ENTANGLEMENT AND BRIDGES IN SPACE-TIME

In previous articles, we saw how 4-dimensional space-time curves under large, massive bodies, giving rise to incredible phenomena. In this article, we'll include certain aspects of quantum mechanics, which will open the door to even more impressive processes.

In this article, we're going to discover one of the most incredible and fascinating recent proposals in theoretical physics and take a journey that could overshadow the script of the best science fiction movie. No one knows yet if this proposal is correct, however, there are serious indications that it may be. If it is finally

If proven correct, this proposal would have a profound impact on how we understand space-time and quantum phenomena. This proposal links two of the most exotic and strange phenomena in existence: wormholes and quantum entanglement.

Wormholes: bridges in space-time

In maximally extended coordinates the equations of general relativity have the following solution for a static spherical black hole (Schwarzschild black hole):

This solution represents two black holes connected by a kind of neck or throat. This neck represents a "bridge in space-time" or a "wormhole." The first physicists to discover this solution were Einstein himself and his student Rosen, which is why this wormhole is called the "Einstein-Rosen Bridge" (ER). For symmetry reasons, the two holes have "reversed" time; that is, while one is a "normal" black hole with attractive gravity, the other is a white hole where bodies are expelled from the hole as if it were repulsive gravity. It should be noted that this wormhole is not traversable; to traverse it, we would need to travel faster than light, which is not permitted.

Entanglement: The Strangest Quantum Phenomenon

Two particles that have been generated under certain special conditions (for example, by the decay of a gamma ray into two photons) behave as if they were a single system (as if they were described by the same wave function) even though they are separated by great distances. It is as if these particles were entangled. This produces truly strange phenomena: suppose both particles have two possible states (for example, spin up and spin down), and suppose we measure the state of one of the particles here on Earth, if

We find that the measurement result is spin up, so the other entangled particle must "automatically" be in the opposite state, i.e., spin down. It's as if by measuring the state of one, we automatically "collapse" the state of the other . Even though these particles are light years apart! How is this possible?

It should be noted that it is not possible to send information faster than light using quantum entanglement. To send any type of information, we always need the support of a classical channel, while it is impossible to transmit information superluminally.

Quantum entanglement was first predicted by Einstein (again the great genius), Podolsky and Rosen, which is why the phenomenon of quantum entanglement is also often referred to as the Einstein-Podolsky-Rosen (EPR) experiment.

Recently, there has been a great deal of work based on a magnitude called "entanglement entropy," which basically measures the degree of entanglement that exists between two quantum systems. In 2010, an article that caused a stir

quite an impact provided evidence that quantum entanglement behaves like the "glue" of space-time: by reducing the degree of entanglement between the degrees of freedom associated with two regions of space-time, the two regions separate and disintegrate! This seems to indicate that, in some way, entanglement would be the glue that holds space-time together!

ER=EPR

It is now that we formulate the incredible proposal recently put forward by theoretical physics: there are studies that demonstrate that the microstates formed by the two black holes connected by an Einstein-Rosen bridge are maximally entangled, that is, the two black holes in the first figure are quantumly entangled.

This means that the Einstein-Rosen bridge implies entanglement, as in the Einstein-Podolsky-Rosen experiment, which is symbolized by the expression ER=EPR. This statement is based on fairly solid principles, so it seems natural to ask whether the converse is also true: whether every pair of entangled particles or systems are linked by an Einstein-Rosen bridge. This is precisely what physicists propose: every entangled quantum system could be linked by a wormhole. Although we know that the ER=EPR proposal is based on more or less solid principles, its converse, EPR=ER, is much more speculative.

If the ER=EPR proposal and its opposite are correct, the particles that form the Hawking radiation emitted by black holes that are quantumly entangled with them would be linked to them through wormholes.

Entangled black holes: a quantum bridge in space-time

Next, we are going to take one of the strangest and most incredible journeys that could, in principle, be made in our Universe. Imagine an area of our Universe millions of years ago: two large clouds of molecular gas immersed in

A magnetic field begins to compress due to the effect of gravity. Due to the presence of the magnetic field, the particles of the molecules that make up the gas will acquire a degree of quantum entanglement, which means that both gas clouds will be entangled. Both clouds continue to compress until they reach critical density (when the mass is compressed to a radius less than R = 2GM/c2) and collapse, forming two spherical, static black holes. Both holes are subsequently attracted by nearby galaxy clusters in opposite directions.

(let's assume something like this were possible) and they end up separating over great distances: one ends up in our galaxy (near Earth) and the other in the Andromeda galaxy 2.5 million light-years away. Now imagine that Earth has managed to establish communication with a civilization in Andromeda (a not very fluid communication with 2.5 million years of waiting between each message) and a scientist named Bob has established friendship with a scientist from Andromeda named Alice. Due to the enormous distances that separate them, Bob will never be able to physically meet Alice, or could he? Now comes the most impressive part: if Bob contacts Alice and they both agree to travel in a spaceship to their respective entangled black holes, they could, in principle, do something incredible: let themselves fall into their respective black holes and physically meet each other inside!

But how is this possible? Because both black holes are entangled, the microstates of both holes are linked by an Einstein-Rosen bridge, and the space-time inside is the same space-time! Bob and Alice could meet inside, bridging the millions of light-years that separate them!

The bad news, of course, is that they would never be able to escape the black hole or their tragic end before colliding with the singularity. Because of this, any information transmitted inside the black hole would be isolated from the rest of the universe, and again, this mechanism could not be used to send information faster than the speed of light.

Conclusions

The ER=EPR proposal is a fascinating, though still speculative, idea. Despite this, there are strong theoretical indications that it could be correct. Indeed, there is theoretical work showing that quantum entanglement may be a fundamental component of the nature of space-time. One thing seems clear: the future of theoretical physics promises to be fascinating and full of surprises.

Sources: Cool horizons for entangled black holes Entanglement: Gravity's long-distance connection Building up spacetime with quantum entanglement ;