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Tangled Up in Spacetime

scientificamerican.com

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Re: Tangled Up in Spacetime

#11

Post by wbhart »

anindha wrote: post #2

I always thought of Einstein's theory of General Relativity as a model. For me it doesn't explain the execution. This to me makes more sense that at a quantum level there are discreet particles that are being acted on according to relativity. I think of it more like a CPU where this is a clock input.

I'm not sure that the idea here is that spacetime is made up of particles, but that it consists of nothing more than (mathematical) relationships between fundamental bits of information. In a sense, the only things that actually exist are the physical things that populate spacetime. Spacetime itself is effectively an illusion that can only be properly described as a set of relationships between the actual real stuff.

Re: Tangled Up in Spacetime

#12

Post by anindha »

anindha wrote: post #8
johncolanduoni wrote: post #6

Earlier quoted context omitted.

Quantum mechanics is pretty field oriented (doubly so for QFT, which is what you're dealing with at that scale) so I don't understand why it would be any less of a "model" than general relativity.

Space and time are very macro concepts according to general relativity. It doesn't actually explain how time elapses differently on one atom vs. another atom only that it does. I am traveling close to the speed to light how is my watching running slower? How do the atoms in my watch know to run slower? I am not suggesting that current quantum mechanics is more than a model, but I think we are along the right path to…

"quantum entanglement of whatever the underlying ‘atoms’ of spacetime are"

If we use this idea there are some space-time atoms, to explain entanglement. That same concept could explain space-time itself better.

It is similar to how Einstein used anomalies in the application of Newtonian physics to light to postulate a more accurate model. Explaining entanglement might be the gateway to explaining space-time more accurately.

Re: Tangled Up in Spacetime

#13

Post by anindha »

wbhart wrote: post #11
anindha wrote: post #2

I always thought of Einstein's theory of General Relativity as a model. For me it doesn't explain the execution. This to me makes more sense that at a quantum level there are discreet particles that are being acted on according to relativity. I think of it more like a CPU where this is a clock input.

I'm not sure that the idea here is that spacetime is made up of particles, but that it consists of nothing more than (mathematical) relationships between fundamental bits of information. In a sense, the only things that actually exist are the physical things that populate spacetime. Spacetime itself is effectively an illusion that can only be properly described as a set of relationships between the actual real stuff.

I think the article is suggesting the opposite to what you are saying.

"quantum entanglement of whatever the underlying ‘atoms’ of spacetime are"

You are arguing Einstein's version of the universe. The disproval of his EPR paper [1] led to the discovery of entanglement.

[1] https://en.wikipedia.org/wiki/EPR_paradox

Re: Tangled Up in Spacetime

#14

Post by johncolanduoni »

anindha wrote: post #12
anindha wrote: post #8

Earlier quoted context omitted.

Space and time are very macro concepts according to general relativity. It doesn't actually explain how time elapses differently on one atom vs. another atom only that it does. I am traveling close to the speed to light how is my watching running slower? How do the atoms in my watch know to run slower? I am not suggesting that current quantum mechanics is more than a model, but I think we are along the right path to…

"quantum entanglement of whatever the underlying ‘atoms’ of spacetime are" If we use this idea there are some space-time atoms, to explain entanglement. That same concept could explain space-time itself better. It is similar to how Einstein used anomalies in the application of Newtonian physics to light to postulate a more accurate model. Explaining entanglement might be the gateway to explaining space-time more accu…

That's not what they're doing at all though... they're looking to use entanglement to explain space time, not use space time to explain entanglement.

Re: Tangled Up in Spacetime

#15

Post by M_Grey »

Scientific American has turned into such a rag... their recent bit about "entangled black holes" was especially cringy.

It's Michio Kaku level of hand wavery and lack of rigor.

Re: Tangled Up in Spacetime

#16

Post by Xcelerate »

M_Grey wrote: post #15

Scientific American has turned into such a rag... their recent bit about "entangled black holes" was especially cringy. It's Michio Kaku level of hand wavery and lack of rigor.

Meh... I thought the article did a decent job given the readership. The goal of putting quantum mechanics on an information-theoretic foundation is indeed a hot research topic lately.

Re: Tangled Up in Spacetime

#17

Post by wbhart »

anindha wrote: post #13
wbhart wrote: post #11

Earlier quoted context omitted.

I'm not sure that the idea here is that spacetime is made up of particles, but that it consists of nothing more than (mathematical) relationships between fundamental bits of information. In a sense, the only things that actually exist are the physical things that populate spacetime. Spacetime itself is effectively an illusion that can only be properly described as a set of relationships between the actual real stuff.

I think the article is suggesting the opposite to what you are saying. "quantum entanglement of whatever the underlying ‘atoms’ of spacetime are" You are arguing Einstein's version of the universe. The disproval of his EPR paper [1] led to the discovery of entanglement. [1] https://en.wikipedia.org/wiki/EPR_paradox

I don't think I am. Entanglement and nonlocality are the best illustrations of the concept. Rather than spacetime being like a fabric, or an actual thing, it is defined only by relationships. This allows particles to be entangled without being right next to each other. In some sense, that entanglement makes those particles right next to each other.

Re: Tangled Up in Spacetime

#18

Post by soVeryTired »

anindha wrote: post #8
johncolanduoni wrote: post #6

Earlier quoted context omitted.

Quantum mechanics is pretty field oriented (doubly so for QFT, which is what you're dealing with at that scale) so I don't understand why it would be any less of a "model" than general relativity.

Space and time are very macro concepts according to general relativity. It doesn't actually explain how time elapses differently on one atom vs. another atom only that it does. I am traveling close to the speed to light how is my watching running slower? How do the atoms in my watch know to run slower? I am not suggesting that current quantum mechanics is more than a model, but I think we are along the right path to…

>I am traveling close to the speed to light how is my watching running slower? How do the atoms in my watch know to run slower?

I think in some sense this is the wrong question to ask. Your watch isn't running slower. The point is that if you're moving, you must be moving relative to something else. Their watch will appear slower to you, and your watch will appear slower to them. The counterintuitive part is that you're both correct.

The reason all this comes about is that both observers measure the speed of light as traveling at the same speed, but they can't agree on the path that the light has taken.

Re: Tangled Up in Spacetime

#19

Post by akiselev »

ianai wrote: post #4

I thought quantized spacetime had already been disproven below a testable range? I.e. Any theorized particles wouldn't be seen by particle accelerators smaller than say a solar system or drastically larger.

Yeah I thought so too. AFAICT the standard model and general relativity are incompatible with any spacetime quantization larger than the Planck scale and that's very far outside of our testable range.

Re: Tangled Up in Spacetime

#20

Post by jsprogrammer »

ianai wrote: post #4

I thought quantized spacetime had already been disproven below a testable range? I.e. Any theorized particles wouldn't be seen by particle accelerators smaller than say a solar system or drastically larger.

The end of the article states that everything it discussed prior is only part of a "toy". It is known that the toy being studied does not fully correspond to our universe.
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