Technology

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.

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.

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?

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.

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.

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

God damn it, they're going to use this to force cloud gaming on us.

Not just latency, but any connection at all. Somewhere there's no signal, like in a submarine.

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.