# Spacetime entanglement

1. Feb 7, 2010

### Auxon

I was just thinking about teleportation and wondered if spacetime could be entangled. Or if you could entangle just selected dimensions. Then that would flip the teleportation problem on it's head.... Any thoughts?

2. Feb 7, 2010

### Frame Dragger

That isn't really a question of physics at all. There is no THING called spacetime that can exchange momentum or some other property with another particle. What would be entangled? This is akin to asking "What would be infinity times zero divided by hope". The answer is that you didn't ask a question in the realm of physics.

3. Feb 7, 2010

### Auxon

So you are saying it's completely outside of the realm of physics to ask if it's possible to, for example, entangle a region of space with another, then apply mass to one, thus effecting the curvature of the other region of space? Perhaps ... but I need more of an explanation why than you are providing, because spacetime has properties ... like coordinates and curvature, so if you can entangle the spin of two photons, could you entangle the coordinates of two points in spacetime? Physically, it may not be meaningful or possible, but mathematically, why not? Is spacetime not a "real thing"? Is curvature of space information? Isn't information and energy equivalent?

If you could entangle regions of spacetime itself, would you be able to create a wormhole, that's the question.

4. Feb 7, 2010

### SpectraCat

Yes, that is what we are saying. You are not using physical terms and concepts in a meaningful way .. for example, how do you "apply mass" to a region of spacetime.

Ok, so write down a mathematical expression of this concept for us to consider.

All semantic (at best), or metaphysical questions.

As Frame-Dragger pointed out, that's not really a question at all, not without a better definition of what you mean by "entangled regions of spacetime".

5. Feb 7, 2010

### DrChinese

First, welcome to PhysicsForums!

You must understand that they "laws of physics" are the laws of physics here. They didn't obtain the status of laws on a whim or because someone forget to check something in an experiment.

Basically, your question amounts to: can I break the laws of physics? Entanglement is a feature of quantum mechanics (QM), which is a generally accepted physically theory. There are many many types of entanglement, mostly discovered by applying known laws to new situations. There is nothing conceptually "new" that wasn't a part of early principles of QM.

On the other hand, General Relativity (GR) describes the laws of spacetime. There is no analogous attribute to GR like entanglement. There is no place for it in the theory at all.

Now, if these theories were actually wrong - always a possibility - then perhaps something like entanglement of sapce, teleportation of matter, or time travel would be possible. But that is unlikely considering the many thousands of experiments that have been done confirming existing laws.

You see, those experiments put such heavy constraints on what the "new & better" theory would look like... it couldn't be much different than the existing one and still explain all of the thousands of experiments which have been run previously. Nonetheless, scientists are always looking for new phenomena. But the place to start is either with a new experiment and/or a new theory that continues to explain the phenomena explained by the old superceded theory. A hypothesis alone - one that violates known laws at that - is not worth much.

6. Feb 7, 2010

### Frame Dragger

You know, I'm not a huge cat fan, but I'll make an exception for you SepctraCat. ;) Thank you for clarifying the matter.

Auxon Why would entanglemnt of any kind lead to a wormhole? You do not understand what Entanglement is, it seems, as the fundamental notion of how particles 'entangle' makes no sense when applied to the concept of space-time.

There is no single "Spacetimeion" to be entangled with a partner. There is no conservation of... anything since what you'd be entangling is the system itself.

What exactly do you think a 'wormhole' would be? What does this have to do with teleportation, and what does ANY of this have to do with Non-Locality?!!?!?!

EDIT: Dr. Chinese is being kind, which he is on a regular basis. Don't be fooled however, you're asking a non-scientific question. There was a fine book I read about Bernhard Riemann, 'Prime Obsession' in which the author (John Berbyshire) talks about a similar issue:

Last edited: Feb 7, 2010
7. Feb 7, 2010

### Auxon

I have a pretty decent layman's understanding of entanglement I thought. I admit this was a crazy idea, it just came to me and I posted it. That being said, I think you guys are a bit quick to call it a non-physical question, that seems extreme, and it's not a metaphysical question. QM and GR are related somehow, obviously. Why can't entanglement apply to spacetime as well - if spacetime does not have a wave function then it makes no sense to ask, is that the bottom line? Is spacetime itself energy or not, if it is energy then surely it has a wave function? That's not metaphysical, is it??

The question then becomes, can entanglement occur in any form of energy. We already know it can be produced with photons and also with macroscopic molecules. How would you entangle mass? Well, if a particle gives mass to all particles, then if you entangle that quantum state, like you do spin, with another particle, then you'd think you could alter the mass of a particle which was entangled in some way. If you alter the mass of one body in space and that gravity force carrier, or Higg's or whatever it is, is entangled with another, then you could curve space by altering the mass of large bodies, and maybe curve space enough to create a wormhole.

Ok, so, the part that you guys seem to say is way off, is the very concept that you could do anything to spacetime in such a way, and that makes sense from the perspective that there is nothing to "grab" ahold of in empty space. You can't grab a point in space, it's relative to the observer, and there's not anything to observe ... or maybe you could think of it as being, all points in space are equivalent in this sense, so there would be nothing you could actually do. However, I also think perhaps if mass curves spacetime, then there has to be some property to measure the curvature (ok, you measure the gravity, no problem but that's not the same thing - I mean, the curvature of spacetime is caused by the presence of mass, but the curvature itself is a property of spacetime that has some field or particle associated with it.

So, then I come around and say, how do we know there isn't a Spacetimeion? I am not saying there is! Just wondering.

What does this have to do with teleportation or non-locality. Well, I was thinking about how it would be easier to try to entangle less particles, less information, so how would you do that? Well, if you move spacetime rather than the object you want to teleport, that's a wormhole, because you curve space to bring point A and B closer together, by somehow controlling mass in the universe at will. Now that sounds impossible, yeah, I know. Not saying it is possible, just a crazy idea. Another effect might be that you are in two places at once, that is, two regions of spacetime would be in superposition.

8. Feb 7, 2010

### Auxon

Yeah, I know it's a crazy thought, I am not a physicist, but I read a ton about physics, and have studied it in some university courses (up to 2nd year). The only problem I have understanding here is why entanglement cannot apply to spacetime, if all things are energy and have equivalence (which we anticipate to be what a TOE would reveal, no?), then why couldn't you also entangle properties of spacetime itself.

Either way I appreciate efforts to help me understand this; just try to explain why spacetime doesn't have particles or wave functions associated with it ... if that's possible or known. If it's unknown, then great.

9. Feb 7, 2010

### Frame Dragger

You need to research the term "Space-Time" in terms of General Relativity. I don't know what else to say that would be plainer? What you're positing is essentially that space is composed of something (like the 'Ether') and those things can be entangled as though they existed in a quantum system.

1.) Space and Time are defined by a different theory than the one which described Entanglement.

2.) Please understand that this is something that arises from the mathematics of GR on one hand, and QM on the other.

Space-Time is deformed by energy-momentum as described by the SET(MET whatever) or RSET in some QM application. Space-Time could be described as, "that which is warped by the passage of energy, and by which warping the path of said energy is determined."

You're mixing popsci concepts of entanglement, general relativity and a very very VERY skewed view of spacetime geometries (and wormholes).

This has all been done before here... https://www.physicsforums.com/archive/index.php/t-14154.html

and to be blunt, before you start asking non-questions, please take the time to at least google "what is space-time made of". :/

10. Feb 7, 2010

### Auxon

I googled "what is space-time made of" and there is no clear answer at all, besides, it's a continuum of space-time coordinates, points of space relative to an observer. I can't find anything that says what space-time actually is.

"Space-Time is deformed by energy-momentum" ... what is deformed? Well I have read some of the posts in the thread you mention but it's late and I don't care anymore except to say two more things:

One: Why does it matter if the concepts came from two separate theories???? So? There has to be relationships and a connection somewhere, entanglement must exist in GR too, and GR in QM and vice-versa, how can they not occupy the same physical principles? I have no idea why that's a problem.

Two: Judging my understanding when I have made one post on this forum is BS. Obviously you don't like to talk to people who have questions about things you are interested in, because otherwise you'd really, really, REALLY learn to just explain what you know and drop your attitude. I'm looking for answers not "YOU DIDN'T GOOGLE IT" BS, when I did, and there isn't a clear answer. You are so full of absolute certainty about something that is not clearly understood or known, and spitting in the face of someone who asks your opinion. How are the research grants going for ya? Make many friends? Yeah I know I am not a physicist! That's why I came and signed up and posted here. Just forget it I regret ever posting at all.

11. Feb 8, 2010

### SpectraCat

Sorry your experience was less than you were hoping for. What we are all trying to tell you (some more gently than others), is that there are a lot of important details that you are ignoring or glossing over in the very phrasing of your questions. Thus we can't even begin to address your questions, because they aren't phrased in meaningful way within the context of physics. It takes most of us a few years of study to get to the point where we can understand why questions such as yours are ill-posed. That also means that there is not likely to be a nice, short explanation of all this that we can just post here for you to read and understand.

EDIT: Furthermore, while both GR and QM have both been verified time and again by experiment, there is currently no *accepted* over-arching theory that unifies both of them, although there have been plenty of attempts. As Dr. Chinese told you in his response, there is no way to describe entanglement in the context of GR. There is also no gravity within the context of QM (loosely stated). In order to answer your question, assuming that it *were* properly phrased, we would need a unified theory, which we do not have.

Last edited: Feb 8, 2010
12. Feb 8, 2010

### Frame Dragger

THANK YOU. If you hadn't posted my next response was going to be one of those less gentle ones you hinted at.

Auxon This isn't easy for me... I'm sorry I was harsh... or even nasty. Yes, it is a difficult question with no answer: 'What is space-time'. Please understand however, that the understanding of entanglement that you believe you possess MUST be terribly incomplete. To understand the theories surrounding it would be to already realize this is a question who's only scientific answer can be: Space-Time is that thing which is deformed by the SET, and by which deformation space and time -like geodesics are determined.

You're going to be dissapointed if you learn more however... there are more questions to work with than answers. Theories that exist now MODEL aspects of reality, but there is no true 'space-time simulator' except the entire uiniverse itself I supppose. Finally... do you think that there is a single unified concept of what 'Time' and 'Space' are?

Particles have some known properties. When a pair are 'created' because of conservation laws, one must act in a manner to conserve some property of the other. Lets say 'spin'. One is up, one must be down. That relationship persists in an Entangled state such that a SINGLE particle and its pair must continue to conserve 'spin'. If one particle becomes an
'up' spin, the other simultaneously becomes 'down'. It's not that simple, but that's the basic idea, that I believe you already understand.

It might seem logical then, that any system has this kind of relationship. WHY do we believe those particles are entangled however? CONSERVATION of 'x'. What is that? A Feature of a given Theory. Outside of that theory, even talking about conserving anything, or spin/charge/momentum/marshmallows etc... doesn't MEAN anything.

Furthermore... you asked about all of this in the context of teleportation, and then wormholes (two different things). A wormhole of a classic type, an Einstein-Rosen Bridge (ERB) may exist, but not even a photon could traverse it. Either way, a 'Wormhole" has to do with the geometry of space-time, not an entangled property. In theory two space-like slices are 'bent' to be closer and connected in such a manner as to bypass the geodesics of 'normal' spacetime.

Finally, the math. GR, and QM are first and foremost theories of math, by math, and for math. ESPECIALLY in the case of QM, language doesn't do it justice unless you already have some knowledge of WHY... and the WHY is in the MATH. Of course, that 'why' and math are always changing, as are interpretations. If you asked Newton what spacetime was, he'd give you a strange look, then say, "You mean to see, what is The Ether which pervades the othwerwise empty space betwixt the fixed stars?". Get it?! PLEASE?!