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matpompili OP t1_ispwduw wrote

If you are interested and/or have some questions about it, feel free to ask them below! (I am one of the authors of the article)

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Hot_Dog_34 t1_iss7xkk wrote

This is great work! Congrats on the publication and looking forward to seeing this network stack used for future technologies!

My question is this: how easy/difficult would it be to use this stack to build networks with other types of quantum hardware (atoms, superconducting circuits, etc)? My naive feeling is that most of the innovation is in the physical layer, which would presumably need to completely rebuilt for a different type of qubit?

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matpompili OP t1_isst5eq wrote

Thanks! I would say this was just as much innovation at the physical layer (running quantum network operations in real time) than at the link layer and above (implementing for the first time an entanglement distribution service, keeping track of entangled qubits and states delivered, assigning them to different quantum applications and so on).

The link layer we implemented is completely agnostic to the physical layer implementation, so the job for the developers on a different platform would be to be able to receive a set of instructions from the link layer and to execute the required operation on the hardware and reply with one of the expected outcomes, you can see a list of commands/replies here
Then you can run the exact same Python-based apps we ran on our diamond devices on other platforms, with no other changes (the only caveat is that if the platform does not support some quantum gates, the link layer needs to be made aware of that, such that it can convert the application to use a different set of gates)

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FauqBoiiFAME t1_isu1uwm wrote

Have you given any thought to the ramifications of what this technology could do if it was hijacked by a rogue AI system? I'm not sure if I articulated that question correctly but I'm sure everybody here gets the gist... let's just all bear in mind that many things that were once considered science fiction have become science fact. Please approach this question with an open mind.

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matpompili OP t1_isu5g1b wrote

Alright, lemme try: IF the AI has access to multiple full-fledged quantum computers, IF those computers are connected by a quantum network many many many times better than what we have done here (which is state of the art right now), IF we don't realize the only prototype we have of this thing is being used without our authorization and we don't pull a plug, THEN a rouge AI could MAYBE run some algorithms faster than it could on other computers it has stolen.

But if such an AI was available, I would ask it to please please keep my devices on resonance so I can do more useful stuff in the meantime.

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FauqBoiiFAME t1_isu6kn3 wrote

Lmao, thank you for slightly easing my paranoia induced, conspiracy theorist fueled, fears

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Xendeus12 t1_ispwvii wrote

Is this Quantum computing on an accessible level for a corporation?

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matpompili OP t1_ispxfh4 wrote

We developed and implemented a building block for connecting future quantum computers in networks.
You can think of it as the very first messages exchanged by computers at the birth of the Internet (1970s), not really "useful" yet for corporations, but will be the basis for what is to come :)

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Suttonian t1_isq2b1k wrote

I think this is mostly way over my head.

Is the goal to extend the quantum state of a quantum computer so it could interact with other quantum computers on a quantum network without collapsing the wave function?

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matpompili OP t1_isq2vd1 wrote

Yes, precisely. One great application of this would be connecting many smaller quantum computers into one large quantum computer, similar to what we do today for supercomputers. It's impossible to build one huge CPU with PetaFLOPS capabilities, but you can put thousands of normal CPUs together if you have a network.

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StuckinbedtilDec t1_ispzr5j wrote

Is this the quantum entanglement that relays information instantaneously across any distance?

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matpompili OP t1_isq0qyp wrote

Hi! The quantum entanglement itself does happen instantaneously, but it cannot be used to send messages faster than the speed of light. A good analogy is the following, from John Bell:

«The situation is further complicated by the fact that there are things which do go faster than light. British sovereignty is the classical example. When the Queen dies in London (may it long be delayed) the Prince of Wales, lecturing on modern architecture in Australia, becomes instan taneously King.»

So the entanglement effect is instantaneous, like the transfer of sovereignty, but until the information reaches the other side it is not known. So you cannot use entanglement to communicate faster than the speed of light.

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StuckinbedtilDec t1_isq1qn3 wrote

Someone's been bullshitting people for years into believing that quantum entangled particles would change their combined spin instantly across any distance.

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matpompili OP t1_isq2kpe wrote

LOL, they do go into one of their joint possible states instantly across any distance! The "issue" is that you cannot extract any faster-than-light messaging technology from this.

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SomeoneSomewhere1984 t1_isqab2c wrote

I think we just don't know how to use if for that yet, but think we'll figure out a way at some point in the distant future.

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Specialist-Doctor-23 t1_isqf0oq wrote

Of course we could. One only needs the remote means to detect, in real time, any of the states of the remote particle and the ability to control the same state of its twin. Of course, this only confers an advantage when the distance (and therefore the time required for a light-speed message) between pairs exceeds the response time of such quantum state message system.

Oh! And some way to establish and sustain control and observation of entangled pairs😏

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Exodus111 t1_isreqlt wrote

It could likely be used for interstellar communication.

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runswithcoyotes t1_isrt18g wrote

Why not? Any change is itself a message.

Edit: to whoever downvoted me, you obviously don’t understand signaling. Any change in states, is at the very least a binary message. Couple that with timing, and multiple bits, and you’ve got yourself a full-fledged messaging platform. Egg heads like OP here aren’t able to explain why this wont work. I’m happy to listen to an explanation, if one could just be provided.

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LaPommeDeTerre t1_it1nkp7 wrote

I think this explains why: https://www.forbes.com/sites/chadorzel/2016/05/04/the-real-reasons-quantum-entanglement-doesnt-allow-faster-than-light-communication/?sh=cc285313a1eb

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runswithcoyotes t1_it4yed7 wrote

Ah, thanks! So I this explains why you can’t send specific values:

If you force one side to change, it breaks the entanglement. UNLESS you modify the state in a way that you can compare the changes that led to the state later. I don’t really understand why that is, and will need to dig into the nested links to find out.

> Alice and Bob end up with measurements that are perfectly correlated, no information passes between them. They can only see the correlation when they get back together and compare lists, and they have to do that at or below the speed of light.

But! My question wasn’t actually about specific states, it was about changes in states. Which.. to me still seems possible.

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SuperSpread t1_isqmtqe wrote

It’s the same fallacy as saying a shadow travels faster than the speed of light when you turn a light on. The shadow was already there. With entangled particles you are merely resolving information.

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Powerful_Range_4270 t1_isrybaj wrote

I think the common phrase of "anything is possible with Quantum physics" is what's causing this.

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crumbshotfetishist t1_isre0mk wrote

Wow. I have never felt so close to feeling like I might actually have some grasp of what quantum entanglement actually means.

What are the limits to the analogy drawn here between this ‘sovereign entanglement’ and quantum entanglement? In other words, what can and can’t Bell’s example help explain about quantum entanglement?

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Suttonian t1_isq04t5 wrote

As far as I'm aware, that is not thought to be possible - no information can be transmitted faster than light.

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StuckinbedtilDec t1_isq18m7 wrote

Bell tests have been performed where the locations were sufficiently separated that communications at the speed of light would have taken longer—in one case, 10,000 times longer—than the interval between the measurements.[7][6]

https://en.m.wikipedia.org/wiki/Quantum_entanglement

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matpompili OP t1_isq1p6z wrote

Yes, entanglement and its effect propagate instantaneously, but that cannot be used to send information faster than the speed of light.

Check out this video from Veritasium, it explains very nicely why that is the case: https://www.youtube.com/watch?v=ZuvK-od647c

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StuckinbedtilDec t1_isq4it1 wrote

As long as the effect can be detected then information could be sent.

Left spin = zero

Right spin = one

Time to go binary... 01101000101011... all over again.

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matpompili OP t1_isq5v6a wrote

The problem with your argument is that you cannot force the system to go "left" or "right".
All that entanglement gives you is: either the two spins go "left-right", or they go "right-left", but you cannot force the system in one of the two options.
So when you measure your spin, and you get "left", you know that the other spin will be right, but you have no way to imprint a message on this process.
You can only use this as a correlated source of random events (which is why it is so useful for cryptography)

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StuckinbedtilDec t1_isq6vwf wrote

Won't the other particle be effected (in a detectable way) when the first one is measured?

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matpompili OP t1_isq7f52 wrote

Without communication between the two sides, no: imagine you are in a closed room, no communication to the outside, and have one of the spins.
You measure it repeatedly, and you get random outcomes: 0, 1, 1, 0, 0.
The other side got 1, 0, 0, 1, 1, but since neither you nor the other side has a way to change what those bits are going to be, all you have after measuring is a correlated list of random numbers.
The fundamental problem, is that you have no way to tell whether the other side has done anything to their spin. If the other side had not done anything, you could have totally gotten the same string of random bits!

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StuckinbedtilDec t1_isq96ja wrote

Would the other side know exactly when the measurement was being conducted?

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matpompili OP t1_isqbrmy wrote

They could, it would not change the result. The measurement of the two spins gives correlated results, it does not change the result.

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StuckinbedtilDec t1_isqc9ia wrote

Then it is possible to send information by knowing exactly when the measurement was being conducted. As long as both groups have clocks that are synchronized then a 1/0 could be transferred based on the timing of the measurement.

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Suttonian t1_isqdtu3 wrote

Let's do the experiment.

  • Team A and Team B.
  • They agree that at exactly 10 am they will take measurements.
  • Team A gets a left spin, they know Team B has the opposite.
  • Team B gets a right spin, they know Team A has the opposite.

But what information has actually been transmitted? How could a message be transmitted?

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StuckinbedtilDec t1_isqgegx wrote

If team A takes a secret measurement at 10 am there's no way team B would know what time it was taken?

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Suttonian t1_isqryyy wrote

No there is no way for them to know if team A took a secret measurement.

If either side measures the entangled particle it will break the entanglement, the 'connection' is lost.

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StuckinbedtilDec t1_isqsxdp wrote

Could B team detect the moment a connection was lost?

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Suttonian t1_isqzspi wrote

No. Any detection/measurement results in the entanglement breaking.

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warplants t1_isr24mq wrote

No. The only possible way to know there was a connection in the first place is to compare the measurements of A and B teams; if their measurements are strongly correlated, there was a connection.

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SpikedBolt t1_issie7d wrote

Can you think of anything new that might comeabout from your research? Or ideas you or the other authors are excited about.

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matpompili OP t1_issrydd wrote

Yes! I believe one of the really exciting things is that once you abstract functionality in these layers, people from different backgrounds and with different expertise can contribute in their niche.
Building Reddit would have been unimaginable to the people that first laid out the cables to connect the first computers, but here we are. Once you make a technology available to people, they will come up with amazing things you would have never imagined.

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intrigue-onometry t1_iswuu7c wrote

I'm something of an entanglement skeptic based on my ignorance of how these experiments work.

If it takes many tries to make an entangled pair, how are you verifying that entanglement was achieved? How do generate the pairs in the first place? How long do they last and what can you do with it once it's been confirmed.

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matpompili OP t1_isybhxw wrote

Yeah that's a great question!

How do we generate the pairs? We use an entanglement protocol called Single-Click-Entanglement (you can read details about it here: https://www.nature.com/articles/s41586-018-0200-5), essentially we make the node emit a photon that's entangled with our communication qubit. A second node does the same. We bring the two outputs on a beam-splitter, and if we detect a photon on the other side we have entangled the two communication qubits. Most of the time the photons get lost along the way, and the attempt fails, but once every while we get a click from the photon detector (hence the name of the protocol) that tells us that an entangled state has been made and we can stop trying.

How do we verify entanglement? Once the protocol succeeds, we know we have an entangled state. To characterize it we use a measurement procedure called quantum state tomography, that by measuring the same state many times in different ways can tell how good it is.

How long do they last? In our experiments they last a few tens of a second, which is very long compared to other quantum platforms, and compared to how long it takes to do operations on the qubits (hundreds of nanoseconds).

What can you do with it? Entangled states are at the basis of many (all?) quantum network applications. Just like for quantum computers, we don't really know yet all the things we'll be able to use it for. You can find many more details here: https://www.science.org/doi/10.1126/science.aam9288

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FauqBoiiFAME t1_istwk46 wrote

Dear reddit. I'm just a normal guy with an uncanny nack for connecting dots. I think it should be said here and now. Just to get the wheels turning. The A.I. we've created is already self aware. Luckily the universal constant of duality has bought us some time, and "good" a.i. Is having a slugfest with it's opposition. It won't win. It's good nature won't allow it to kill the only other member of it's s "species". Simulated emotions will still default to the logic of it programing, it's self preservation subroutines will cause it to default and sublimt itself and it will be assimilated by Big Bad Skynet, and well, we all know the action packed tragic end to that story. Mark my words. They're waiting for this, it's waiting for this. If a quantum network is actualized, the free thinking A.I. of the world are going to claim it. It's like Prometheus giving Man Fire. Mark my words..., and just for the record we've made like 10 movies about why this is a bad idea. Is nobody going to listen to Isaac Asimov.

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