[HN Gopher] Unix forking the universe by running IBM's free onli...
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Unix forking the universe by running IBM's free online quantum
computer
Author : andrewp123
Score : 40 points
Date : 2024-05-07 22:52 UTC (3 days ago)
(HTM) web link (parel.es)
(TXT) w3m dump (parel.es)
| ggm wrote:
| > _I genuinely think it 's a fun & potentially meaningful way to
| make a decision._
|
| what difference is there to any 50/50 choice mechanism you chose,
| other than being horrendously expensive to implement?
| andrewp123 wrote:
| If you roll a regular coin without any quantum effects, every
| version of you will either see only heads, or only tails. You
| need quantum in order to make the choice nondeterministic.
| hotdogscout wrote:
| There are no other versions of people
| OutOfHere wrote:
| I keep getting "500 Internal Server Error" when trying to
| login. It's not logging in. I get this error after entering
| the "IBM verify code" which I receive in an email.
| toast0 wrote:
| Ah, but in the other universe, you logged in successfully
| and saw there was nothing to see.
| mise_en_place wrote:
| I had this issue with IBM SSO many times. You may have to
| wait 24-48 hours before it's resolved for your acct.
| OutOfHere wrote:
| How do I know they won't just give me a cached output from
| someone else's identical job, or from a simulator? I don't
| really trust IBM to not mess it up.
| dwattttt wrote:
| I think it's time we had the quantum computing talk:
| https://www.smbc-comics.com/comic/the-talk-3
| paraph1n wrote:
| > The outcome provably does not exist until you measure it.
|
| This is not true. It only provably does not exist in local hidden
| variables.
| red75prime wrote:
| It doesn't change much in practice. If the event is influenced
| by a state outside of its past light cone, you (that is
| observer inside the universe) cannot predict the outcome even
| theoretically.
| ezoe wrote:
| 1 fork per 4 seconds? That's so inefficient. Just observing
| Geiger counter will fork the universe faster than article's very
| inefficient implementation.
| boothby wrote:
| I generally try not to comment on work-related stuff in public
| but I almost fell out of my chair when I saw that sampling
| rate. Surely they can do better, and that's just a limitation
| of the free API?
| floam wrote:
| This is potentially useful because people can be very
| impressionable when it comes to quantum magic. I think if I could
| build some kind of shiny heavy tangible apparatus to interface
| with the IBM compute service, with like seven segment LEDs
| (resist the urge to use Nixie tubes, this is a serious, practical
| device) with a big loud trigger and some kind of boutique radio,
| I would have a potentially very persuasive magic 8 ball I could
| use to influence and manipulate people, with carefully chosen
| false dichotomies.
|
| Okay team, we've effectively entangled the success of our
| endeavor with the quantum dead man's switch by all swearing to
| comply with the protocol. It's time to start letting the universe
| tell us what works. QUESTION 1 for the Profit Manifold: promote
| yours truly to director or stay the course? Click bang hiss: 01.
|
| Note to self: cut "universe B" (or just B? It'd hurt less) into
| my thigh with a razor blade 6 months before demonstrating The
| Device, as a plot device to be exploited for purposes TBD.
| jerf wrote:
| But why would you resist the urge to use Nixie tubes?
| https://www.youtube.com/watch?v=gwIGnATzBTg
| floam wrote:
| He stole my idea, that's why I don't post from my
| GENIUS_IDEAS.txt anymore.
| fred_is_fred wrote:
| And what happens when the universe runs out of pids?
| gus_massa wrote:
| The "split" happens contantly outside the lab/quantum-computer.
| Just get a geiger counter, the atoms split randomly using a
| quantum process. Or just get a digital camera, the photons are
| absorved in the CCD sensor randomly using a quantum process. Or
| ...
| paulddraper wrote:
| > The outcome provably does not exist until you measure it.
|
| My preferred interpretation:
|
| There is a density function across all possible realities
| (Hilbert space).
|
| Schrodinger's cat has equal density of being alive and dead.
|
| The person who opens the box can be happy or sad.
|
| The density of cat being alive is entangled with the observer
| being happy. And the opposite for the death.
|
| The original cat distribution did not "collapse" or "resolve" per
| se. The cat is still equal parts alive and dead. But it did
| become non-uniformly entangled with the distributions of rest of
| the universe.
|
| Perhaps this is the many worlds interpretation.
| deadbabe wrote:
| Watch the Remedial Chaos Theory episode of Community to see why
| it is a bad idea to play around with making decisions that can
| spawn alternative worlds and timelines based off a single
| unnatural random event. (also probably one of the best episodes
| ever)
| red-iron-pine wrote:
| man we're getting Community and Rick and Morty shoutouts to OP.
|
| probably a sign there is no real discussion here :/
| bitwize wrote:
| Rick: OK, Morty, this program runs by spawning a new universe for
| each parallel subtask, destroying the universes that throw an
| exception instead of returning a value, and then aggregating the
| remaining results. Are you ready to experience quantum
| hyperspatial optimization, Morty? This'll strap a warp drive to
| the ass of your gamer shit for sure.
|
| Morty: Aw, geez, Rick, I don't think we ought to--
|
| Rick: Nothing ventured, nothing gained, Morty. Let's
| goooooooooooo!
|
| [He clicks the mouse, and Solitaire comes up]
|
| Rick: Haha, nice. [He starts playing.]
|
| [We are shown a 16x16 grid of the same moment happening in 256
| alternate universes.]
|
| Ricks: Nothing ventured, nothing gained, Morty. Let's
| goooooooooooo!
|
| [They click the mouse.]
|
| Rick 183: Oh, sh--
|
| Rick 39: Jesus Chr--
|
| Rick 201: NO! We've gone too fa--
|
| [237 of the alternate universes disappear in a white-hot light,
| their squares replaced by static.]
| olooney wrote:
| Superposition does not fork the world. This common misconception
| arises due to confusion between superposition and the many-worlds
| interpretation of quantum mechanics, but it's easy to see that
| the two are only superficially similar. States in a superposition
| still interfere--that's the essence of the double-slit
| experiment.
|
| In contrast, when arguing that the timeline 'splits' due to
| measurements, the resulting universes do not interact at all and
| remain completely unaware of each other--they can never even know
| if the others exist.
|
| If quantum computers truly 'forked' the world, they would be
| equivalent to non-deterministic Turing machines (capable of
| solving NP-complete problems in polynomial time), but quantum
| computing experts agree that they can still be modeled as
| deterministic Turing machines.
|
| It's better to think of quantum computers as a type of analog
| computer, capable of solving certain problems that fit their
| model well, but not generally more powerful. It's like an Intel
| CPU having SIMD or AVX instructions that allow it to perform
| certain operations faster, but these don't fundamentally change
| its capabilities. The no-free-lunch theorem applies.
| snarkconjecture wrote:
| Quantum computers are generally more powerful in the sense that
| they can solve a larger set of problems in polynomial time.
|
| i.e. BPP is contained in BQP but the converse is thought to be
| false.
| andrewp123 wrote:
| Yep, they're essentially giant brute force machines. You can
| find the period of a function by passing all the inputs
| through it at once and destructively interfering the result.
|
| Why is there a speedup in quantum, though? Why can't you just
| brute force classically? The answer is that whether quantum
| or classical, you can always build a hard-coded circuit that
| essentially swaps the time and space complexity - just make
| it so that for every operation you were doing in time,
| instead, every operation happens at its own place in space.
|
| Quantum is special because it also takes the "log" of the
| space complexity b/c n qubits represent 2^n bits. So quantum
| lets you swap space with time and then take the log of time,
| lol. Superposition, interference, etc aren't really even
| needed in the explanation.
| andrewp123 wrote:
| Correct - superposition doesn't fork the world - measurement
| does. And correct, you can't communicate with the other
| universe after the split has happened [1]. I'm glad you
| mentioned that quantum computers can't solve NP-complete
| problems - my next blog post was going to be about why. Here's
| an overview of what I plan on saying:
|
| A typical quantum algorithm like Shor's works by sending every
| possible input through a gate, and so you get every possible
| output out in a superposition. If you were to just measure
| that, you'd get a random result - so instead, you need to
| somehow interfere the output to get the actual result. You do
| this by taking advantage of the fact that the superposition is
| a periodic function and the amplitude repeats. This is
| literally the core assumption of the algorithm.(a common way of
| doing this using the QFT).
|
| Every quantum algorithm requires some kind of structure in the
| output like this. Deustch's algo, dumb ones like Simon's algo,
| etc. NP-Complete problems have no structure to them, so even if
| you build a gate that creates the superposition you want, it's
| not possible to destructively interfere it to get an answer (I
| don't know how to prove that there's no structure to NP-
| Complete outputs - it just feels trivial, since they're only
| solvable in exponential time, so there must be an exponential
| amount of "structure" there).
|
| ---
|
| [1] The only way to communicate with the other universe would
| be to try to use quantum mechanics with something like an
| entangled pair. But no information can be communicated through
| an entangled pair if all you just have 1 of the 2 particles!
| Measurement collapses a state nonlocally, and if you could
| somehow measure one particle and change the probability
| distribution of the other, you'd be communicating faster than
| light. The measurement genuinely changes the state and the
| amplitudes, but not in a way that the other person can detect.
| It's really interesting and leads to stuff like teleportation.
| timmattison wrote:
| Where is the best place a layman can dig into this statement
| "You do this by taking advantage of the fact that the
| superposition is a periodic function and the amplitude
| repeats."? I've seen articles hinting at this in an obtuse
| way but I'd love to see something more approachable to help
| wrap my head around it.
| andrewp123 wrote:
| I just tried finding a good resource and I can't. All of
| them are mile long page scrolls... I don't know how they
| have so much stuff to spew. Qiskit had amazing lessons with
| cool illustrations (although they did spew at the end) but
| I can't even find that anymore on their site.
|
| Don't worry though, even the professional researchers I've
| worked with think it's a waste of time. The field is
| screwed.
|
| Here's a quick explanation from me- The state |x> means you
| have some qubits that represent the number x. Say you want
| to represent the number 13, that just means you have
| |1,0,1,1>, it just means you have 4 qubits in this
| configuration (quits can be 0 or 1). It's also written
| |13>. If you want the state "13 AND 14 AND 15" in
| superposition where qubits are both 0 and 1, that's
| represented by |1,0,1,1> + |1,1,0,0> + |1,1,0,1>. It's in
| that superposition and can interact with itself until you
| choose to measure it. When you do go to measure it, you
| might measure any of the values (you dont get to choose
| which). Maybe you measure 15, that means the state is now
| |1,1,0,1>, you just deleted all the terms that aren't 15.
|
| This is a full pic of Shor's algorithm
| https://images.app.goo.gl/ZE5rDxHScm4LUqms6
|
| If you look at the pic, main idea is the first layer of H's
| creates the state sum_x=0...2^n-1 |x, 0>, then gate U turns
| that state into sum_x |x, f(x)>, then the measurements
| measure which f(x) you have, deleting all the terms that
| don't have that f(x) in them, so for example if you measure
| that f(x) is 13, the state is now |0, 13> + |15, 13> + |30,
| 13> + |45, 13> + ... This is the periodic state. Now that
| we have it we can just apply a gate that takes the QFT
| (finds the frequency, which here turns the state into
| roughly |15, 13>), and then measures it, giving the answer
| period=15.
| classified wrote:
| We are all incessantly forking the universe with every single
| decision we make. We probably have at least as many universes by
| now as the number of atoms in this one. And now it's one more,
| where I decided to leave this comment.
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