The Two General's Problem

tlb wrote:But it does not matter, because it is irrelevant to the question of FTL communication in the Honorverse; unless you can show how to create a Qubit out of distinct gravity pulses. Here is a Wikipedia article for more information: No-communication theorem

To summarise: we have qubits and they store one quantum superposition state. It's not binary (0 or 1), but a superposition of all possible values. We can read them and, when we do, we get a discrete, concrete value that is not in superposition. Why that happens, why the quantum decoherence happens at or before we read, is what Physicists can't yet explain.

But all our qubits are local. And as the link above says: there's no transmission of information, even if the quantum-entangled particles had been apart from each other. This is Einstein's "spooky action at a distance" which he disliked but could not explain away.

Qubits can be of a non-binary value, so they contain more information than one bit of information. You know what else contains more than one bit of information? Analogue signals. You don't need quantum to transmit more than one bit with a wave transition. In fact, all of our more modern modulation techniques for transmitting binary over an analogue channel (e.g., radio waves) use this technique. In-universe, the fact that the initial FTL comms couldn't transmit more information must have been a limitation of how precise the transmitter could shape the waveform and how precise the receiver was to extract the information from it, in the presence of noise. For example, it's unknown whether they could vary the amplitude of the signal, or even whether gravitic waves have such a degree of freedom.

Out-of-universe, it's because RFC is not an electrical engineer with knowledge of digital signalling and wrote those books at an era where 300/75 bps modems were still common.

ThinksMarkedly wrote:

tlb wrote:But it does not matter, because it is irrelevant to the question of FTL communication in the Honorverse; unless you can show how to create a Qubit out of distinct gravity pulses. Here is a Wikipedia article for more information: No-communication theorem

To summarise: we have qubits and they store one quantum superposition state. It's not binary (0 or 1), but a superposition of all possible values. We can read them and, when we do, we get a discrete, concrete value that is not in superposition. Why that happens, why the quantum decoherence happens at or before we read, is what Physicists can't yet explain.

But all our qubits are local. And as the link above says: there's no transmission of information, even if the quantum-entangled particles had been apart from each other. This is Einstein's "spooky action at a distance" which he disliked but could not explain away.

Qubits can be of a non-binary value, so they contain more information than one bit of information. You know what else contains more than one bit of information? Analogue signals. You don't need quantum to transmit more than one bit with a wave transition. In fact, all of our more modern modulation techniques for transmitting binary over an analogue channel (e.g., radio waves) use this technique. In-universe, the fact that the initial FTL comms couldn't transmit more information must have been a limitation of how precise the transmitter could shape the waveform and how precise the receiver was to extract the information from it, in the presence of noise. For example, it's unknown whether they could vary the amplitude of the signal, or even whether gravitic waves have such a degree of freedom.

Out-of-universe, it's because RFC is not an electrical engineer with knowledge of digital signalling and wrote those books at an era where 300/75 bps modems were still common.

Watch the documentary. The link is fixed. I think. It's a foregone conclusion; a quantum computer prototype is successful.

Don't get the quantum computer mixed up with its plumbing system that keeps it only a degree above minus 400 degrees fahrenheit. The refrigerator looks like a quantum computer. Apparently everyone makes that mistake. Anyway, watch the documentary. That ship has sailed.

Don't get quantum computing mixed up with quantum communication as some of you are. Quite different.

penny wrote:Don't get quantum computing mixed up with quantum communication as some of you are. Quite different.

You are the one that introduced quantum computing into a discussion of FTL communication, by suggesting that transmitting a qubit would be easy. How you expected to simulate a qubit with gravity spikes traveling on the Alpha wall has yet to be explained.

PS: Whether quantum computing exists in the Honorverse is something that author has not disclosed.

tlb wrote:PS: Whether quantum computing exists in the Honorverse is something that author has not disclosed.

And that's still true about our own Universe. We can do quantum computing and we do have quantum computers, but they're massive, expensive, and unreliable. Not only are they very susceptible to perturbation, you cannot guarantee that the answer you got was the "correct" one either, so often the same calculation has to be done 2 or 3 times to be sure. This all means quantum computing could turn out to be impractical for its already pretty restricted use, let alone general-purpose.

And this all depends on there being no breakthrough in another area to make the quantum computers irrelevant, either by solving the NP problems in Maths, or by other types of analogue-digital computer systems solving the problems quantum computers can solve. Or, for that matter, volumes of scale allowing such levels of brute forcing that break even over quantum computers.

ThinksMarkedly wrote:And that's still true about our own Universe. We can do quantum computing and we do have quantum computers, but they're massive, expensive, and unreliable. Not only are they very susceptible to perturbation, you cannot guarantee that the answer you got was the "correct" one either, so often the same calculation has to be done 2 or 3 times to be sure.

Though sometimes you're working a problem that's hard to calculate but easy to verify and so, instead of rerunning it on the quantum computer several times you can just quickly have a classical computer check the answer. But it's still (at least at present) necessary to double-check somehow.

Integer factorization of large numbers is in that class of hard to find, easy to check. If you've got a number that's the product of two large primes (as you'd have if attacking RSA cryptography) it's exceptionally hard for a classical computer to find those two factors. But if given two purported factors it's trivial for one to multiply them together and verify whether that results in the original product.

penny wrote:AND... the reason I deleted the particular duplicate post upstream is because the one that I kept was error free, the closing ']' was there and the quote displayed correctly. And... because I had control and I can delete any duplicates of my own posts as I damn well please Clear?

The new link DOES now work, which is an improvement; perhaps that is a difference in the browsers that we use. Since you did not supply the title, I guessed at the one you wanted based on what momentarily flashed on the screen.

Of course, you have complete control over whether you choose to either erase or delete a duplicate post. But if the most recent post is correct and the earlier is not correct, then it would be NEATER to copy the text from the correct version and replace the earlier version (making it correct) and then deleting the last (now redundant) post. I have faced this same problem (but they truly were duplicate) and was forced to erase one, rather than deleting; but that was due to someone else posting something new, before I could react.

But you do you, it is only a matter of aesthetics.

ThinksMarkedly wrote:And that's still true about our own Universe. We can do quantum computing and we do have quantum computers, but they're massive, expensive, and unreliable. Not only are they very susceptible to perturbation, you cannot guarantee that the answer you got was the "correct" one either, so often the same calculation has to be done 2 or 3 times to be sure.

Jonathan_S wrote:Though sometimes you're working a problem that's hard to calculate but easy to verify and so, instead of rerunning it on the quantum computer several times you can just quickly have a classical computer check the answer. But it's still (at least at present) necessary to double-check somehow.

Indeed, that's how you'd know the answer the quantum computer spit out was bogus.

Not that classical computers are 100% free of errors either. But the failure rate is in the order of 1e-7 or lower, not 33%, so unless you're Google, AWS, or Microsoft, you usually don't see them. Except for AI training, where those cloud providers are now selling 10,000-node+ clusters for weeks at a time...

ThinksMarkedly wrote:And that's still true about our own Universe. We can do quantum computing and we do have quantum computers, but they're massive, expensive, and unreliable. Not only are they very susceptible to perturbation, you cannot guarantee that the answer you got was the "correct" one either, so often the same calculation has to be done 2 or 3 times to be sure.

Jonathan_S wrote:Though sometimes you're working a problem that's hard to calculate but easy to verify and so, instead of rerunning it on the quantum computer several times you can just quickly have a classical computer check the answer. But it's still (at least at present) necessary to double-check somehow.

ThinksMarkedly wrote:Indeed, that's how you'd know the answer the quantum computer spit out was bogus.

But the possibilities are still intriguing for every problem that is easy to check, but hard to compute. If a quantum computer can generate attempted solutions and those can be quickly checked to find a correct answer; then the quantum computer's output is not purely bogus. It would be worthless, if its attempted solutions were no better than guesses; but every time it suggested a good answer, then it is providing value.

penny wrote:I continue to be hacked. DoA attacks, you name it. It took me 45 minutes to log in this time. And that is good. Sometimes it is days. Nothing works correctly when I am logged in.

Are you writing specifically about this website? Because it was not confined to you, the site was broken from sometime Wednesday until sometime Sunday. This does not seem to be the result of hacking, but instead the database requiring maintenance (as stated in the error message about excess users (?) that finally was displayed from Thursday until it was fixed).

tlb wrote:

penny wrote:AND... the reason I deleted the particular duplicate post upstream is because the one that I kept was error free, the closing ']' was there and the quote displayed correctly. And... because I had control and I can delete any duplicates of my own posts as I damn well please Clear?

The new link DOES now work, which is an improvement; perhaps that is a difference in the browsers that we use. Since you did not supply the title, I guessed at the one you wanted based on what momentarily flashed on the screen.

Of course, you have complete control over whether you choose to either erase or delete a duplicate post. But if the most recent post is correct and the earlier is not correct, then it would be NEATER to copy the text from the correct version and replace the earlier version (making it correct) and then deleting the last (now redundant) post. I have faced this same problem (but they truly were duplicate) and was forced to erase one, rather than deleting; but that was due to someone else posting something new, before I could react.

But you do you, it is only a matter of aesthetics.

IF you’d listen to me for a change maybe you will finally get it.

Actually, I DID NOT HAVE COMPLETE CONTROL over which post I chose to erase or delete. The option to “erase” or “delete” often does not exist under my circumstances. Nothing works when I finally gain access to the site. I have to do my thing quickly before I lose any more of the little control that I have or before I am booted out. Often I cannot scroll through posts, or other pages of posts, etc. Oftentimes the site is soooooo sloooooow that it is unusable.

So, caring about being being NEAT -- and copying and pasting -- are luxuries I do not have! Even my edits do not take. I didn’t find out about the duplicate until much too late because I could not view the post I had made. I had lost access to the site!

So, please, for the third or fourth or fifth time, stop pretending “to know the troubles I see.” You did the same thing to Brigade_XO when he had a duplicate post as if you personally know what the site was doing during his presence. Stop being arrogant and rude. You don’t know the trouble another poster may be facing… unless you are the trouble.

So. Again. Please stop. I grow weary of fighting the site, hackers, and you too.