Quantum internet within grasp as scientists show off entanglement demo Researchers in the Netherlands have shown they can transmit quantum information via an intermediary node, a feature necessary to make the so-called quantum internet possible. In recent years, scientists have argued that the quantum internet presents a more desirable network for transferring secure data, in addition to being …
Quantum teleportation via entanglement is notorious for taking place instantly, with the information travelling faster than light. Before getting all het up about breaking the laws of physics, it is worth recalling somebody-or-other's theorem that the quantum information cannot be read and interpreted classically until some reference information is received. This reference information is obliged to travel no faster than light - in the present case, the setting-up of the entanglement between Bob and Charlie. In everyday terms, what with the various delays while everybody fiddles around, the connection still works at sublight speed. Still cool, though.
No objects accelerate to the speed of light. Massless bosons (photons) travel at the speed of light, all other particles have rest mass and therefore are doomed to be subluminal ( though some, such as neutrinos, tend to travel so close to lightspeed that we are unable to measure the difference).
Another way of looking at the inconsistency is to note that for massive particles, velocity is always relative to the observer, whereas entanglement is an absolute property. They are not related in any way.
You can split photons into 2 lower energy photons, but can you split them into 3? If you can, I can show you why Entanglement is really a bogus filtering effect (your "filter for photons that are successfully entangled", as you put it in that Delft "loophole free proof of entanglement").
Split a photon into 3, P1,P2,P3. By definition they are entangled, but you always add an extra filtering step before your Bells test... you filter for photons with one or two identical properties ("CheckProperties") as proof of successful entanglement, then you measure the other properties ("ProofProperties") and "hey presto" those are the same, so the act of measuring the properties must have set them, you claim.
So, we have 3 "successful" entangled photons, filter for the photons such that CheckProperties(P1) == CheckProperties(P2), ok, so now we have the triplet of entangled photons. If entanglement worked as claimed, then P3 is also entangled, and there is no need to filter for CheckProperties(P3) == CheckProperties(P1) or CheckProperties(P3) == CheckProperties(P2), ProofProperties(P3) will equal ProofProperties(P1) and ProofProperties(P2).
BUT IT WOULD NOT WORK. You would indeed have to filter also for the subset of photons P3 whose CheckProperties(P3) also match CheckProperties(P1) or CheckProperties(P2)....
You do not set the state of photon (or matter), simply by measuring it, and as if by magic the interactions it had in the past, which now are defined, fix themselves up to work with the newly known state, and in turn, the photons/matter that *those* secondary photons/matter interacted with are also partly know, so they change too, and so on propagating throughout the universe, faster than light, backwards in time.... just because you took a measurement, the universe changed to fix itself such that your result would now be correct. When I put it that way doesn't it sound ridiculous?
So what's happening?
You are not measuring the properties of P1, you are measuring the properties of the net effect between detector D1 and the photon P1, between D2 and its photon P2, and between D3 and its photon P3.
It honestly should be obvious to you, that two oscillatory components form a spin, and 3 form a translational 'waddle' ('velocity'), and that you're ignoring the motions in the detector when assuming those properties are solely properties of the 'entangled' photons. You already know from red shift the detector and photons are some sort of net effect, you are ignore that.
It is true that P1, P2 and P3 are in a defined connected state, because you split them from 1 photon. But the detectors are *not* in a unified state. When you filter for CheckProperties(p1) == CheckProperties(p2), you are actually filtering for CheckProperties(net(p1,d1)) == CheckProperties(net(p2,d2)), ensuring that the detector's relationship to the photon is the same for P1 and P2.
The unknown remaining for P3 is D3, or rather net(P3,D3).
That is why you still need to filter for P3 (as measured by detected D3).
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If you cannot split photons into 3, split them into 2 and 2 again to get P1, P2, P3, and P4. Filter to ensure entanglement for P1 to P2 and P2 to P3, then run your ProofProperties against P4 vs the rest.... it won't work. It's just a bit more complicated, and gives you more room to self-delude.
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You can deduce a lot, if you stop simply parroting the falsehood you learned to parrot. Electric must be an oscillating force, all forces must be oscillating because they take time to propagate, time = oscillations of the underlying field. The universe cannot be uniform, and particles, if you could ever see one, (and not just the net effect between them), would be close to specific orientations in that field. Think of a half spin, the F2 flip of that is from the electric field, not the particle. There cannot be 3 independant dimensions, because the 3 dimensions we preceive are 3 net effects. The underlying single force must propagate infinitely fast (H0), and 'mass' must be a repeating pattern that moves net zero in a field relative to an observer.
See those particles apparently spinning backwards in time, as observed in a cloud chamber? Merely shutter effects. The net interaction between the oscillating field and particle. Well seriously, did you never question why those go back in time?
So much is there right in front of you, but first, set aside Schroedinger.
Yes indeed. I assume you mean, can a photon be split into three entangled photons? Based on that, you ask, "So what's happening?"
For that you must turn to the combined Hamiltonian of the three photons and what happens to it when one of them is measured. And for that you need to understand what a Hamiltonian is and how to manipulate the maths. No. I'm not going to help you there.
Often, rather than split a quantum, it can be easier to entangle two pre-existing quanta. So you would end up say splitting one photon into Alice and Bob's pair, and then entangling Charlie's with Bob's. That's even if photons are the quanta used to create and store the entangled states, as opposed to just transferring them.
The key takeaway here is that you are way out of your depth and talking bollocks.
"The photon is a fundamental particle. That means it can't be split or decomposed."
Actually, it can. A rare example of our AC getting it right. It only happens spontaneously with very high-energy gamma rays, but a gamma-ray photon can split into two lower-energy photons.
With the help of some unusual materials it can also go the other way; shine a beam of a certain frequency in, and you get a beam of twice the frequency out.
In all cases, energy is conserved.
More generally any fundamental particle can, with sufficient mucking about, be persuaded to become one or more different ones. What else could the LHC create Higgs bosons from, if not from the detritus of the other fundamental particles being fed into it?
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Quantum, like fusion or AI, always seems to be within our grasp and they have been for years.
The human mind, let's call it Real Intelligence (RI), is a marvelous thing for generating ideas. But implementing those ideas always seems to be a bit beyond our grasp.
I am not a scientist, so I can't comment on the significance of these developments (like today's other announcement - using the quantum technique Stimulated Raman Adiabatic Passage in very-long baseline interferometry). But as an observer through the years, I don't expect we will be grasping anything any time soon.
Still, a pint for the boffins who continue to try and understand what's what.
My point was that the phrase 'within our grasp' almost always over promises.
Computers are a good example. Semiconductors were discovered in the mid 19th century, decades before the electron was discovered. Decades later the transistor was proposed but it would be more decades before one was produced. Integrated circuits followed about a decade later and a decade after that we got the first microprocessor - the Intel 4004 in 1971. Five years later we got Woz's Apple 1 circuit board and in 1977 we got the first real personal computers: the Apple II, the PET 2001 from Commodore Business Machines, and the TRS-80 Model I from Tandy Corporation).
Implementation of ideas takes time. And, as they say, "There's many a slip 'twixt the cup and the lip."
But I remain hopeful of eventual success.
As I see it, if this technology matures it will be used to build an even more centralized internet than the one we already have. If I understand correctly, this is all physical layer stuff and not inherently secure. Maybe I have not followed the idea.
OK - I understand quantum entanglement. In fact I understood it before it started getting called quantum entanglement. (It was the EPR paradox when I were a lad). So the result of observing one half of the entangled subsystem is that it then forces the other half into a known state
What I've not got my head around, and never seems to be explained, is how you use this for useful information transmission ? Thing is that the outcome of the first observation is random (quantum acausality). You can't decide what state you're forcing the remote half of the system into - you're stuck with whatever you're given.
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