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#1 2012-10-11 04:10:16

Terraformer
Member
From: Logres
Registered: 2007-08-27
Posts: 3,362
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Cross-temporal quantum entanglement

http://www.newscientist.com/article/mg2 … trick.html
http://arxiv.org/pdf/1209.4191v1.pdf

Presumably, this can be done with other quantum particles, such as electrons.

What I want to know is, since the state of photon 1 was already known prior to it's entanglement with photon 4, then surely that means that there were constraints on photon 4 - before it was entangled. Which poses the question of whether they had to use photon 1, or whether they could have decided to use one which has a state they are happy with. The problem with that is, they can then knowingly influence the state of photon 4 instantaneously. That is, they can send classical information instantaneously, backwards and forwards through time, with all the problems that poses for physics...

Say Alice generates an entangled pair of photons. She then sends on photon to Bob, with the previously agreed instruction that he will measure it at a specific time. She then generates entangled photons until she measures one with a specific state, after which she performs an entanglement swap with it's pair and the photon she has remaining from her original pair. Now the photon she has measured is entangled with Bob's photon, and thus the quantum state of Bob's photon depends upon Alice's measurement. However, Alice got to choose which photon she entangled with Bob's *after* she'd measured it, and thus could determine the state of Bob's photon - however far they were separated by.

It's a fiddly ansible, but it's an ansible nonetheless. Any ideas where my reasoning may be wrong?


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#2 2012-10-11 08:28:24

louis
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From: UK
Registered: 2008-03-24
Posts: 6,859

Re: Cross-temporal quantum entanglement

I think this conundrum has been around for many years. I am sure I read something to the effect that you could take one sub atomic particle to the other end of the universe and it would still interact instantaneously with the other entangled particle.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#3 2012-10-11 10:27:28

Terraformer
Member
From: Logres
Registered: 2007-08-27
Posts: 3,362
Website

Re: Cross-temporal quantum entanglement

Well yes, but the trouble was that you couldn't change the state of the particle without breaking the entanglement, so causality was safe. Now, I'm not so sure. Even if a single bit of classical information can be transmitted instantaneously, a lot of modern physics comes crashing down. Which is why I suspect my reasoning is wrong somewhere... It seems too obivous to miss.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#4 2012-10-11 17:00:03

SarK0Y
Banned
From: Russia
Registered: 2012-08-23
Posts: 19

Re: Cross-temporal quantum entanglement

HD (hyperdimensional) Physics it can explain as transition of particle from one subSpace to another.

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#5 2012-10-11 20:48:53

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,742
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Re: Cross-temporal quantum entanglement

Quantum mechanics was first discovered by Dr. Schrödinger. Scientists couldn't understand how subatomic particles moved, but Dr. Schrödinger took a different approach. He didn't try to explain why, he said they just do. We have observed they move in a predictable way, and these mathematical formulae match what we see. So those formulae must be it. There is no "why", it just does. Dr. Einstein really didn't like the fact there wasn't an explanation why, but it works. Since Dr. Schrödinger, quantum mechanics has grown greatly, but it's still based on "there is no why, the formulae just work".

Then there's my idea. I have looked at various problems in physics and came up with my own idea. It's strongly based on relativity. I start with the fact relativity predicts an object moving very quickly will shrink in its direction of motion. As it approaches the speed of light, its length approaches zero. My idea is that the dimension in the direction of travel collapses as you approach the speed of light. If you could achieve the speed of light, the dimension would collapse entirely. It would become a 3 dimension object in our 4 dimensional space-time universe. Photons are such a particle. Also relativity calculates that time inside the object slows, at the speed of light time stops. So the waves that compose a photon act like a solid object because time inside the photon has stopped entirely. On the other had, an electron travels very close to the speed of light, but not quite. That means it has 3 and a fraction dimensions. That fractional dimension is described by fractal mathematics. And fractal mathematics is the mathematics of chaos. That's why electrons act to chaotically. The faster they go, the more their 4th dimension shrinks, changing the fractal.

I call my idea "flexible dimension theory". There's an even longer explanation why. More physics stuff.

Quantum mechanics says entangled particle pairs respond instantaneously across any distance. There is no signal, no propagation delay, and no limit to its range. According to flexible dimension theory, the dimension between the particles has collapsed, so from the perspective of the particles they're sitting on one another. There is no propagation delay because there is no distance separating them. You can separate them by any distance in real space, but because they particle has the dimension between them collapsed, the particles to not "see" that distance. The following analogy is crude, but it makes it easy to understand. Let the 3 dimensions of space be represented by a 2 dimensional sheet of paper. Place to markers (marbles, post-it-notes, or whatever) on the sheet. Now bend the sheet around so the paper touches between the markers. The markers are now separated by twice the thickness of that piece of paper, but they're pressing against each other. If you jiggle one marker, the other marker moves with it. The signal does not pass across the length of the paper; it passes though where they touch. The distance along the paper could be any distance, the length of 8.5"x11" office paper, a piece of newspaper, or a paper tape that's miles long, it doesn't matter. The "signal" when you jiggle one marker does not pass along the length of the paper, passes through where the two makers are pressed against each other.

Of course if you were to knock one particle so that the collapsed dimension no longer aligns with its partner, then the quantum link will be broken. As soon as the collapsed dimension no longer aligns, any signal has to pass through real space, so distance then becomes real. The trick is to "entangle" the waves within the particles so they interact with one another, then they'll hold onto each other. A gentle push will just cause the waves to push back. But if you push a particle hard enough so the collapsed dimension no longer aligns with it's partner, then the link is broken.

Establishing a link would be very difficult. Imagine aiming a bullet where your target is the diameter of an electron, while it's moving randomly at greater than 90% the speed of light. Good luck hitting that! But two electrons in the same orbital of an atom are so close, the alignment could be off by something like 60% and the dimension would still pass through its partner. The trick is to tease a pair of electrons out from a single atom without breaking the entanglement link. Then place one electron in the quantum well in one microchip (Integrated Circuit), place it's partner in the quantum well of another. Viola, you have a quantum communication device.

Because a photon travels at the speed of light, it has no randomness and its range is infinite. However, if flexible dimension theory is correct, an electron on partially collapses one dimension. That means randomness and a limit to its range. I have no idea how to calculate that range. I would hope it's significant, such as the distance from Earth to Mars. Containing a photon is very difficult, basically no one can do it now. So using photons is not practical. Electrons require a microchip; something modern electronics knows how to make quite well.

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#6 2012-10-12 01:11:48

bobunf
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From: Phoenix, AZ
Registered: 2005-11-21
Posts: 223

Re: Cross-temporal quantum entanglement

My favorite quote from Erwin Schrödinger with respect to quantum theory: "I don't like it, and I'm sorry I had anything to do with it."

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#7 2012-10-12 01:42:39

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,742
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Re: Cross-temporal quantum entanglement

Reading the article, it's not a dramatic as the author makes it sound. They entangle photons 1 & 2, then measure #1 with a destructive method. Then entangle 3 & 4. Then entangle 2 & 3. The result, they claim, is that 4 is now "entangled" with 1, after 1 is destroyed. But then they didn't manipulate the particle, they just measured it. That's like saying person 1 writes a book in collaboration with person 2. Then years later a pair of younger people, persons 3 & 4 write a book. Then they introduce senior citizen called person 2 to university student person 3. But while they do so, person 3 is still talking to his locker partner from university, person 4. Then someone notices that a book written by person 4 somehow looks just like something that person 1 wrote! Un huh. Right. The idea was passed on, so why are you surprised that person 4 now writes something similar to person 1, long after person 1 died. You know, this can be done much simpler by having person 4 read a book written by person 1 long after person 1 died. Is that "quantum entanglement" across time? No, I would call it "reading". The quantum state of a series of photons were set, using one to set the state of another. It's a chain. Once you set the state, it stays.

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#8 2012-10-12 06:01:30

Terraformer
Member
From: Logres
Registered: 2007-08-27
Posts: 3,362
Website

Re: Cross-temporal quantum entanglement

Well, not quite. My problem with the entanglement here is that Alice is free to choose which photon she entangles with Bob's, so she is able to determine Bob's photon's state from an arbritary distance...

Of course, doing so might cause the entanglement swap to fail, preserving causality.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#9 2020-09-10 14:04:37

tahanson43206
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Registered: 2018-04-27
Posts: 7,305

Re: Cross-temporal quantum entanglement

For SpaceNut ... I think it might be time to bring this topic back into view.

It turns out that RobertDyck was a contributor to the first round, and he has reenergized the topic in his Large Ship topic.

He asked a question along the lines of "how do you maintain a photon across a distance"  Apparently there are teams hard at work in an attempt to answer that question.

I thought this quote from Wikipedia was helpful ... it indicates entanglement has been observed in a wide variety of particles ...

Quantum entanglement has been demonstrated experimentally with photons, neutrinos, electrons, molecules as large as buckyballs, and even small diamonds. The utilization of entanglement in communication, computation and quantum radar is a very active area of research and development.
Quantum entanglement - Wikipedia
en.wikipedia.org/wiki/Quantum_entanglement

(th)

Last edited by tahanson43206 (2020-09-10 14:05:09)

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#10 2020-09-10 17:34:46

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,078

Re: Cross-temporal quantum entanglement

The photon and its data elements over distance is not the issue its how a collection of them move from the start towards a far off destination. Much like the rays of them blasting away from the sun they tend to spread out and once far enough away from the source gravity of anything that passes by them will influence that straight line that they are leaving on. This is what happens with solar energy collection the farther you are from the sun as the m^2 power creation drops with distance....

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#11 2021-01-26 13:44:40

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,305

Re: Cross-temporal quantum entanglement

Here is a hint of work ongoing in China ...

It is taken from an advertisement for an eNewsletter. 

Scientists create integrated quantum communication network

Scientists from the University of Science and Technology of China have established what they claim is the world's first integrated quantum communication network.

if anyone in the forum readership is interested my guess is it would not be difficult to find the original source material.

As stated earlier in this topic, such a communications system would be advantageous for the Large Ship project.

(th)

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#12 2021-03-26 09:36:00

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,305

Re: Cross-temporal quantum entanglement

Here's another update in the Quantum space ...

https://www.msn.com/en-us/news/technolo … d=msedgdhp

Quantum computing: How basic broadband fiber could pave the way to the next breakthrough
Daphne Leprince-Ringuet  2 hrs ago
The usefulness of most quantum computers is still significantly limited by the low number of qubits that hardware can support. But simple fiber optic cables – just like the ones used for broadband connections – could be the answer.

The implication of this announcement, if I understand it correctly, is that quantum computing may develop even faster than it already is.

One detail included in the article is that the temperature at which quantum computing takes place is millikelvins.  I'd not heard this detail before, so appreciate the update.

(th)

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#13 2021-05-12 07:07:11

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,305

Re: Cross-temporal quantum entanglement

https://www.yahoo.com/finance/news/dutc … 43063.html

I noted that there’s more than one type of quantum computer. He countered “We are in principle agnostic to what kind of quantum computer it is. All we do at the moment is we focus on the microwave part, so we can work with superconducting qubits, topological qubits etc. We can convert microwaves to optical signals and they can talk to each other. Currently, the only competitors I know are all the in the academic world. So this is we're the first company to actually starts building a real product.”

Rick Hao, Principal with Speedinvest’s Deep Tech team, added: “ We want to invest in seed-stage deep technology startups that shape the future and QphoX is well-positioned to make a major impact. Over the next couple of years, there will be rapid progress in quantum computers. Quantum Modem, the product developed by QphoX, enables the development of quantum computers that demonstrate quantum advantage by combining separate quantum processors."

(th)

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#14 2021-08-01 16:18:01

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,305

Re: Cross-temporal quantum entanglement

For SpaceNut .... there is only one topic with "quantum" in the title, but I think it should work for this post:

248,939,925 km [22.0 km/s] at 9:30

1050 1113 1177

https://www.yahoo.com/entertainment/goo … 41870.html

Google’s time crystal discovery is so big, we can’t fully comprehend it
Chris Smith
Sun, August 1, 2021 1:09 PM

To understand Google’s time crystals, The Next Web offers a great analogy with snowflakes. They have unique designs, as the atoms are arranged in specific ways. Snow falls, melts, water evaporates, and then it’ll eventually become snow again. All these processes involve energy exchanges. A time crystal would be like having a snowflake that can change between two configurations back and forth with no energy usage or energy loss. Time crystals can have their cake and eat it too, and they can do it perpetually.

This is speculative, but the article is written for a Scientific American audience, so I think it might of interest to NewMars.

(th)

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