This is a most excellent place for technology news and articles.
The firm’s T‑Labs used commercially available Qunnect hardware to demo quantum teleportation over 30km of live
Bit disingenuous to talk about teleporting things along a fiber line...
Also shows a fundamental misunderstanding of how quantum entanglement works...
But it's actually pretty huge that they're able to do this.
As someone who also doesn't fully understand quantum entanglement.. is it that when two particles are entangled and far apart, when we observe them they will always be in the same state? Is there any way to manipulate that state? If so, it seems like it would be pretty straight forward to use it for faster than light communications.
when we observe them they will always be in the same state?
The two particles are in different but directly related states. For example in some circumstances with two entangled photons, it will necessarily be the case that one photon has horizontal polarisation and the other vertical polarisation. The two will never have the same polarisation.
You can't know which photon is in which state without measuring one. The effect of taking the measurement travels faster than the speed of light. Measurement is not manipulating though; you can't say "I want this photon to be measured as vertically polarised", you can only ask "what is the polarisation of this photon?". So you can't transmit information faster than light, unfortunately.
Quantum is a struggle for me to understand because, I feel like the current explanations don’t suffice why you can’t transmit information. To me, this still sounds perfectly viable for information transfer… just don’t encode information via polarization. You would encode it as a primitive derived from whether or not state collapse has happened yet or not.
Using the same/similar mechanism they can use to determine collapse happens to both entangled particles at the same time (faster than light), can they not also determine whether or not collapse has happened at all?
Maybe it’s that checking for collapse will actually cause collapse, thus ruining the information channel. But, perhaps then, you just add more entangled particles. Have some mechanism established with “throwaway” particles that can have their state collapsed either as a chain reaction or via the polling process.
Obviously I’m not the smarted person here… probably a lot wrong with my above assumption. But my point is really that explanations about quantum seem to be unsupportive to the claims they make about quantum.
I'd recommend this excellent series if you want a good grounding:
https://www.rigb.org/explore-science/explore/video/arrows-time-back-future-1999
And I also found this video which I haven't watched but I expect will be good and probably attacks your pondering more directly:
AFAIU you can't determine whether the state on the other side has been collapsed. All you can say with certainty is the state on the other side after you have collapsed yours.
Yep
The thing is if it's entangled, why is there a fiber cable?
If it's teleportation, why is there a cable?
However what actually makes consciousness in a brain is (hypothetically, technically) microtubules forming a very tiny cable inside of which quantum superposition is able to be maintained while we are conscious. When even brief quantum entanglement used to be insanely hard anywhere and an environment like the brain considered impossible.
Like, it's hard to tell what really happened from OPs article. But there should be much better articles explaining it, and this could actually end up being crazy important. Like, 20-30 years from now this might be how we finally get a real AI.
Quick edit:
Like, rather than one straight line to send data, if this can maintain even just entanglement in a simple fiber optic cable...
Then that's huge.
If they just stretched a string between two containment chambers that each have an entangled particle, then what purpose is the string even serving?
what actually makes consciousness in a brain is (hypothetically, technically) microtubules
This is only a proposed theory, it's very far from accepted fact.
Any source on your claim about consciousness? Sounds very speculative.
Thanks, that’s an interesting read. Still stand by my opinion that your statement is overly confident in explaining consciousness.
Penrose published a book on it in 1989.
For literal decades the only thing that ruled it out was the ability for quantum entanglement in the brain. Less than 2 years ago we proved not only was that possible, but quantum super position could be sustained for as long as we're awake.
It's a pretty safe time to be confident, even without accounting for Penrose being the literal smartest person on the planet.
Like, I'm not big on "appeals to authority" but if Sir Roger Penrose spends 37 years saying something is true, and just continually gets proven more right over the decades...
It's not as far reaching as you seem to believe.
Like, gravity is just a theory too, shit is harder than people realize it is to prove.
not a big fan of 'appeal to authority '
Literally glazing the guy sloppy style and basing their whole world view on a single random dude. Sorry, on 'the smartest guy in the planert'.
Gravity is just a theory
Ah I see the problem. I opened a thread with the word 'quantum' on it. Lmao
I think you’re doing your argument a disservice by comparing it to theory of gravity. But I do appreciate learning about this hypothesis and that there is actual experimentation going on. Thanks again for sharing.
My non scientific intuitive guess is that the cable is there to reliably create the entanglement conditions.
when two particles are entangled and far apart, when we observe them they will always be in the same state?
They will be opposite states of each other the moment observing collapses their waveform. This effectively removes their entangled state. It cannot be used to communicate information faster than c.
So there's a lot of incorrect assumptions and outright wrong ideas of how quantum entanglement is going to be used in a quantum network, or even a quantum Internet.
A hard rule: information cannot be sent faster than the speed of light.
When news articles try to summarize quantum teleportation, they incorrectly imply that information is being transmitted instantly. Quantum entanglement is not intended to send information. It's meant to act like a hash or checksum. The magic in it is it enables both sender and receiver to know that their communication has been tampered with.
It has further use with encryption, but again, it's to facilitate the encryption. The information is still being transmitted as light through the fiber network.
Quantum cryptosystems don't move data faster than light but the payload is 'teleported' as in the data isn't sent over the connection.
The entangled states are sent in such a way that when combined with previously transmitted qbits and sampled, the data appears at the receiving end without it ever going through the intermediary (a bit of handwavery because nobody actually understands quantum mechanics, especially physicists.
It is teleportation but not in a way that is FTL, all of the components of the data transmission obey the laws of physics... we just live in a world where the laws of physics allow for some weird and unintuitive shit.
You're not wrong in that the connection's security is absolute, any attempt by an attacker to read the data would disrupt the entangled states in unexpected ways which will result in an essentially random output. So if you're getting data through the link then you know 100% that it is not being intercepted. It isn't possible to copy quantum states for spooky physics reasons, so there is no such thing as a quantum wire tap.
There are nonlocal effects in quantum mechanics but I am not sure I would consider quantum teleportation to be one of them. Quantum teleportation may look at first glance to be nonlocal but it can be trivially fit to local hidden variable models, such as Spekkens' toy model, which makes it at least seem to me to belong in the class of local algorithms.
You have to remember that what is being "transferred" is a statistical description, not something physically tangible, and only observable in a large sample size (an ensemble). Hence, it would be a strange to think that the qubit is like holding a register of its entire quantum state and then that register is disappearing and reappearing on another qubit. The total information in the quantum state only exists in an ensemble.
In an individual run of the experiment, clearly, the joint measurement of 2 bits of information and its transmission over a classical channel is not transmitting the entire quantum state, but the quantum state is not something that exists in an individual run of the experiment anyways. The total information transmitted over an ensemble is much greater can would provide sufficient information to move the statistical description of one of the qubits to another entirely locally.
The complete quantum state is transmitted through the classical channel over the whole ensemble, and not in an individual run of the experiment. Hence, it can be replicated in a local model. It only looks like more than 2 bits of data is moving from one qubit to the other if you treat the quantum state as if it actually is a real physical property of a single qubit, because obviously that is not something that can be specified with 2 bits of information, but an ensemble can indeed encode a continuous distribution.
This is essentially a trivial feature known to any experimentalist, and it needs to be mentioned only because it is stated in many textbooks on quantum mechanics that the wave function is a characteristic of the state of a single particle. If this were so, it would be of interest to perform such a measurement on a single particle (say an electron) which would allow us to determine its own individual wave function. No such measurement is possible.
Dmitry Blokhintsev
Here's a trivially simple analogy. We describe a system in a statistical distribution of a single bit with [a; b] where a is the probability of 0 and b is the probability of 1. This is a continuous distribution and thus cannot be specified with just 1 bit of information. But we set up a protocol where I measure this bit and send you the bit's value, and then you set your own bit to match what you received. The statistics on your bit now will also be guaranteed to be [a; b]. How is it that we transmitted a continuous statistical description that cannot be specified in just 1 bit with only 1 bit of information? Because we didn't. In every single individual trial, we are always just transmitting 1 single bit. The statistical descriptions refer to an ensemble, and so you have to consider the amount of information actually transmitted over the ensemble.
A qubit's quantum state has 2 degrees of freedom, as it can it be specified on the Bloch sphere with just an angle and a rotation. The amount of data transmitted over the classical channel is 2 bits. Over an ensemble, those 2 bits would become 2 continuous values, and thus the classical channel over an ensemble contains the exact degrees of freedom needed to describe the complete quantum state of a single qubit.
They do everything, just to avoid direct peering with Cloudflare
I would like to know what the advantages are. I mean whats the point?
Theoretically, zero latency. If you don't have to wait for a photon to get all the way from one end of a line to another, that can improve a lot of things.
I'm not sure what the fiber is doing here, but if they can get it working without that, they could drive rovers around Mars in real time, instead of waiting the 4-24 minute delay each way when sending/receiving signals.
Or streaming video games could be actually playable instead of frustrating messes.
Have we ever actually proved it can exceed the speed of light in information travel? I swear I have seen stuff where its theorized the speed of light is also the speed of causality
Nope, the actual information must still be transported via a classical no quantum (and trusted) channel so that both ends can match their statistics and thus deduce the crytographic keys from the qunatum signals. And thats it what its all about: key exchange
thanks. I had forgotten about that I think mainly because I can't wrap my mind around how it works like if its intercepted and used then it will confirm that its void and produce a new one or such.
Yes. If you could transport information faster than the speed of light, it's easy to find examples that break causality, where an observer sees a message arrive before he sees it being sent.
I'd argue that that would be breaking our ability to properly interpret causality, not that causality itself breaks. Things still occur in the order they happen regardless of what order we see them happen from different perspectives.
No, not if the observer can see the message arrive first, and immediately send a faster than light signal to the sender that turns off their transmitter, preventing the sending of their message.
If they see the message arrive, it has already been sent (and received). Not seeing it get sent yet doesn't mean it hasn't happened yet. You're not accounting for the frame of reference translation involved. Some of the information in your example has travel time. None of that information starts traveling before the things that created that information occurred, though. Even if it might look like that from some perspectives. It won't look like that to others.
God damn it, they're going to use this to force cloud gaming on us.
The lack of affordable consumer: harddrives, ssds, RAM, and gpus will do that long before they get this working.
But latency is the determining factor in cloud gaming, not the hardware. The speed of light is the bottleneck.
I'm aware. It's a trash experience currently. But that won't stop them from pushing it anyway, now that personal machines are being priced out of the market.
I mean, if you have enough hardware in the form of giant power-sucking data centers in every town, the latency could get pretty low! /s
The fiber is there because the data is being sent through the fiber as photons like usual. There is no zero latency happening at all and it will not allow rovers to be controlled remotely in real time. That would break causality. This has more to do with encryption and the inability to wiretap without detection.
automated quantum stock trading in 5....4....3....2....1...
As far as I understand this, it's not zero latency, it's safer key exchange possible for some encryption based on a physical and not mathematical principle.
Would be cool, of course, if they really could achieve zero latency. That could do wonders to various infrastructure efficiency. Say, allow for electric grids and internet backbone lines to know of spreading load changes to optimize for them.
There's going to be latency because the NIC on both ends still communicates with copper to the rest of the computer system(s.)
Still going to be faster than a fiber connection or copper. Not to mention the latency induced by say the IEX Magic Box.
Is there a quantum block chain for crypto currency yet?
