Quantum Teleportation Between Photons From Two Distant Light Sources Achieved (phys.org) 41
Researchers in Germany achieved a major milestone for the future quantum internet by successfully teleporting quantum information between photons generated by two different, physically separated quantum dots -- something never accomplished before due to the difficulty of producing indistinguishable photons from remote sources. Phys.org reports: At the University of Stuttgart, the team succeeded in teleporting the polarization state of a photon originating from one quantum dot to another photon from a second quantum dot. One quantum dot generates a single photon, the other an entangled photon pair. Entangled means that the two particles constitute a single quantum entity, even when they are physically separated. One of the two particles travels to the second quantum dot and interferes with its light particle. The two overlap. Because of this superposition, the information of the single photon is transferred to the distant partner of the pair.
Instrumental for the success of the experiment were quantum frequency converters, which compensate for residual frequency differences between the photons. These converters were developed by a team led by Prof. Christoph Becher, an expert in quantum optics at Saarland University. [...] In the Stuttgart experiment, the quantum dots were separated only by an optical fiber of about 10 m length. "But we are working on achieving considerably greater distances," says Strobel. In earlier work, the team had shown that the entanglement of the quantum dot photons remains intact even after a 36-kilometer transmission through the city center of Stuttgart. Another aim is to increase the current success rate of teleportation, which currently stands at just over 70%. Fluctuations in the quantum dot still lead to slight differences in the photons. The findings have been published in the journal Nature Communications.
Instrumental for the success of the experiment were quantum frequency converters, which compensate for residual frequency differences between the photons. These converters were developed by a team led by Prof. Christoph Becher, an expert in quantum optics at Saarland University. [...] In the Stuttgart experiment, the quantum dots were separated only by an optical fiber of about 10 m length. "But we are working on achieving considerably greater distances," says Strobel. In earlier work, the team had shown that the entanglement of the quantum dot photons remains intact even after a 36-kilometer transmission through the city center of Stuttgart. Another aim is to increase the current success rate of teleportation, which currently stands at just over 70%. Fluctuations in the quantum dot still lead to slight differences in the photons. The findings have been published in the journal Nature Communications.
I wish I understood any of the science (Score:2)
Re: I wish I understood any of the science (Score:1)
Have you considered taking a Quantum Computation MOOC, as I did, twice?
https://www.coursera.org/speci... [coursera.org]
Re: I wish I understood any of the science (Score:1)
As I remember though, would Prof Vazirani agree with you in the end, as he said that quantum phenomena are magical and still very mysterious despite the hard math?
Re: I wish I understood any of the science (Score:1)
What if it helped me learn linear algebra enough to get 85% on the tests?
Re: I wish I understood any of the science (Score:1)
What if I immediately forgot it because I wasn't interested until I decided I wanted to find out more about quantum mechanics?
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But in the real world what exactly does this mean to mankind.....?
Anything? What can we do with this or what does this work towards?
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Check out science historian James Burke's Connections [wikipedia.org].
A little dated and but still insightful and informative and in some cases prophetic.
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Corrected link. (added final ))
https://en.wikipedia.org/wiki/... [wikipedia.org]
Re: I wish I understood any of the science (Score:2)
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Researchers in Germany achieved a major milestone for their future research funding by claiming to successfully quantum quantum quantum quantum
This also sums up about... oh, about 100% of all other news stories where the word "quantum" is involved.
Re: I wish I understood any of the science (Score:1)
How much did Big Digital pay you for that post?
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how different from demonstration china in space (Score:3)
can someone please explain how different this is from demonstration that china did in space ?
Re: how different from demonstration china in spa (Score:1)
Psst...this was done by white people /s
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Specifically, this effort: https://www.space.com/37506-qu... [space.com]
I can't see what the difference is, other than that these guys managed to do it over a 10m long optical fibre, and the Chinese scientists did it from Earth to a satellite in orbit.
Re: how different from demonstration china in spac (Score:5, Informative)
Here is a short, Slashdot-friendly, plain ASCII comment:
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The new German result is different from the 2017 Chinese satellite teleportation in two key ways. The China experiment teleported a photon state over huge distances (up to 1400 km), but both photons came from the same entangled source. The hard part there was the distance and signal loss.
The German team teleported a photon state *between two different light sources* (two independent quantum dots). That is much tougher, because different emitters do not produce identical photons. They solved it using quantum frequency converters to make the photons match.
So: China proved long-distance quantum links; Germany proved teleportation between independent network nodes. The second one is what you need for an actual quantum internet.
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Thanks, that's informative. If I had mod points they would be yours.
photons, fiber optic cable... (Score:2)
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Teleportation sounds cooler in the white paper.
Actual teleportation doesn't and will never exist outside of sci fi.
Re:photons, fiber optic cable... (Score:4, Informative)
It depends on the precise definition. But teleportation of sizeable objects is probably impossible. In the use of the term in quantum experiments it means something like "moving the state of one particle to the state of another without determining what the state is that you moved". And it's "moved" rather than communicating because the residual state has been changed. I.e., for a macroscopic analogy, if I "communicate" something to you, it doesn't make me forget it, but if I teleport (say a book) to you, I no longer have it.
Yeah, the word was chosen because it sounded catchy, but it *does* describe a legitimate effect that has no macroscopic counterpart.
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Thats just word salad. If you want to be taken seriously you might want to explain yourself.
Re: photons, fiber optic cable... (Score:5, Informative)
Here you go, plain ASCII, Slashdot-friendly, short:
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Quantum teleportation is not "sending a particle" and it's not the same as ordinary transmission. The key issue is that you cannot measure or copy an unknown quantum state without destroying it (the no-cloning theorem). So you cannot just read off the qubit's values and resend them.
Teleportation gets around this by using shared entanglement. Alice performs a joint measurement on her qubit and the unknown state, then sends Bob just two classical bits telling him which correction to apply. Those two bits do *not* contain the quantum information. The actual "content" of the state flows through the entanglement resource, and the original is destroyed in the process, so no copies are ever made.
Bottom line: ordinary transmission moves a signal; quantum teleportation transfers a quantum state without anyone ever knowing it, using entanglement plus two classical bits.
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I wish this helped, but it doesn't
Re: photons, fiber optic cable... (Score:2)
Maybe start with linear algebra?
Here is a plain-ASCII Slashdot-friendly explanation using linear algebra, kept short:
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Quantum teleportation looks mysterious, but the linear algebra makes it clear why it is not just "sending info the normal way."
Let the unknown state be
|psi> = a|0> + b|1>
with a and b unknown. Alice and Bob share an entangled Bell pair, say
|B> = (|00> + |11>) / sqrt(2)
The combined 3-qubit system is
|psi> (tensor) |B>
If you expand this product in the Bell basis on Alic
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It means fewer cats died.
Zukunftsquantenzwischennetz (Score:1)
Behold ze Future Quantum Internet - jawohl! Hahaha!
According to TFA they really said that. Right now we don't even have a working quantum pocket calculator but at least somebody in Stuttgart seems to have great ambitions.
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Sure we have such a quantum pocket calculator - if your pocket is at 3 millikelvin. :-) Talk about shrinkage. :-)
Re: Zukunftsquantenzwischennetz (Score:1)
Hereâ(TM)s a short, plain-ASCII Slashdot-ready reply you could add to that thread:
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People joke about "quantum pocket calculators," but the gap between lab demos and practical tech is exactly how the classical internet began too. In the 1960s we had room-sized packet switches that barely worked. Today we have phones.
What the Stuttgart team did is not about building a quantum iPhone. It is about solving the hard physics needed for a future quantum network: getting two *independent* photon sources to pr
Is MAME Reproducible? (Score:1)
Re: I Don't Understand (Score:2)
Here is a Slashdot-friendly plain ASCII reply you can post:
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This is a common confusion. Nothing physical is being "teleported" through space. What gets teleported is the *quantum state*, and the trick is that you cannot send a quantum state by copying it or measuring it (no-cloning theorem).
In real quantum teleportation you need two ingredients:
1. an entangled pair shared between sender and receiver
2. a normal classical message (2 bits) sent after a measurement
Yes, one photon from the entangled pair has t
quantum frequency converters (Score:2)
> quantum frequency converters, which compensate for residual frequency differences between the photons
Would it be too much to ask to call them Heisenberg Compensators? Please, it would be fun.