bunchberry

@bunchberry@lemmy.world

• ⁨Comment⁩ on ⁨xkcd #3134: Wavefunction Collapse⁩ ⁨⁨6⁩ ⁨hours⁩ ago⁩:

  That’s the thing, though. Einstein’s interpretation did not require a “miracle” because his interpretation was merely to believe quantum mechanics is incomplete because we don’t currently fully understand “what happens down there.” It was more of a statement of “I don’t know” and “we don’t have the full picture” rather than trying to put forward a full picture. Most people agree that GR is merely an approximation for a more fundamental theory and there is a lot of work on speculative models to potentially replace it one day, like String Theory or Loop Quantum Gravity. But it has become rather taboo to suggest that maybe quantum mechanics is not the most fundamental “final” theory either and that maybe potential speculative replacements for it should be studied as well.

  Those were the kinds of things that interested Einstein in his later years. He had published a paper “Does Schrodinger’s Wave Mechanics Completely Determine the Motion of a System, or Only Statistically?” where he proposed an underlying model similar to pilot wave theory, although later retracted it because it was later showed to him to be nonlocal and he hoped to get rid of then nonlocal aspect of it. He had published a paper earlier titled “Does Field Theory Offer Possibilities for the Solution of the Quantum Problem?” in which he had hoped to figure out if you could use an overdetermined system of differential equations to restrict the possible initial configurations of the system such that it would not be physically possible for the experimenter to choose the initial conditions of the experiment freely. If he was still alive today, he would probably take interest in the works of people like Gerard 't Hooft.

• ⁨Comment⁩ on ⁨xkcd #3134: Wavefunction Collapse⁩ ⁨⁨12⁩ ⁨hours⁩ ago⁩:

  My issue with the orthodox interpretations is not that they are random but that they contain miracles. This was John Bell’s original criticism that people seem to have forgotten. The Copenhagen interpretation says that there is a quantum world until you look, then a miracle happens, and you have a classical result, but it does not tell you at all how this process actually works. The Many Worlds Interpretation, which is the second most popular, just denies that the classical world made up of observable particles in 3D space where experiments actually have outcomes does not actually exist and is a grand illusion created by the conscious mind, but also cannot explain how this illusion can possibly come about and just says it has something to do with consciousness. They just punt the miracle over to neuroscience and ultimately do not answer anything either. A lot of people think Einstein wasn’t the biggest of quantum mechanics due to the randomness, but if you actually read his works, he was clear the issue was that it does not give you a coherent complete picture of reality, so he just thought it was incomplete, an approximation of a more fundamental theory that we have yet to discover.

• ⁨Comment⁩ on ⁨Not stealing⁩ ⁨⁨3⁩ ⁨days⁩ ago⁩:

  Well if there was public daycare to take the stress off of parents who couldn’t deal with it then it wouldn’t be as big of an issue.

• ⁨Comment⁩ on ⁨when ur higher than sagan⁩ ⁨⁨3⁩ ⁨days⁩ ago⁩:

  yeah yeah I’m sure quantum mechanics makes us all immortal if that makes you feel better 🤣

• ⁨Comment⁩ on ⁨No, the Chinese Have Not Broken Modern Encryption Systems with a Quantum Computer - Schneier on Security⁩ ⁨⁨9⁩ ⁨months⁩ ago⁩:

  Honestly, the random number generation on quantum computers is practically useless. Speeds will not get anywhere near as close to a pseudorandom number generator, and there are very simple ones you can implement that are blazing fast, far faster than any quantum computer will spit out, and produce numbers that are widely considered in the industry to be cryptographically secure. You can use AES for example as a PRNG and most modern CPUs like x86 processor have hardware-level AES implementation. This is why modern computers allow you to encrypt your drive, because you can have like a file that is a terabyte big that is encrypted but your CPU can decrypt it as fast as it takes for the window to pop up after you double-click it.

  While PRNG does require an entropy pool, the entropy pool does not need to be large, you can spit out terabytes of cryptographically secure pseudorandom numbers on a fraction of a kilobyte of entropy data, and again, most modern CPUs actually include instructions to grab this entropy data, such as Intel’s CPUs have an RDSEED instruction which let you grab thermal noise from the CPU. In order to avoid someone discovering a potential exploit, most modern OSes will mix into this pool other sources as well, like fluctuations in fan voltage.

  Indeed, used to with Linux, you had a separate way to read random numbers directly from the entropy pool and another way to read pseudorandom numbers, those being /dev/random and /dev/urandom. If you read from the entropy pool, if it ran out, the program would freeze until it could collect more, so some old Linux programs you would see the program freeze until you did things like move your mouse around.

  But you don’t see this anymore because generating enormous amounts of cryptograpphysically secure random nubmers is so easy with modern algorithms that modern Linux just collects a little bit of entropy at boot and it uses that to generate all pseudorandom numbers after, and just got rid of needing to read it directly, both /dev/random and /dev/urandom now just internally in the OS have the same behavior. Any time your PC needs a random number it just pulls from the pseudorandom number generator that was configured at boot, and you have just from the short window of collecting entropy data at boot the ability to generate sufficient pseudorandom numbers basically forever, and these are the numbers used for any cryptographic application you may choose to run.

  The point of all this is to just say random number generation is genuinely a solved problem, people don’t get just how easy it is to basically produce practically infinite cryptographically secure pseudorandom numbers. While on paper quantum computers are “more secure” because their random numbers would be truly random, in practice you literally would never notice a difference. If you gave two PhD mathematicians or statisticians the same message, one encrypted using a quantum random number generator and one encrypted with a PRNG like AES or ChaCha20, and asked them to decipher them, they would not be able to decipher either. In fact, I doubt they would even be able to identify which one was even encoded using the quantum random number generator. A string of random numbers looks just as “random” to any random number test suite whether or not it came from a QRNG or a high-quality PRNG (usually called CSPRNG).

• ⁨Comment⁩ on ⁨The universe is bottle-necked at processor speed⁩ ⁨⁨9⁩ ⁨months⁩ ago⁩:

  the study that found the universe is not locally real. Things only happen once they are observed

  This is only true if you operate under a very specific and strict criterion of “realism” known as metaphysical realism. Einstein put forward a criterion of what he thought this philosophy implied for a physical theory, and his criterion is sometimes called scientific realism.

  Metaphysical realism is a very complex philosophy. One of its premises is that there exists an “absolute” reality where all objects are made up of properties that are entirely independent of perspective. Everything we perceive is wholly dependent upon perspective, so metaphysical realism claims that what we perceive is not “true” reality but sort of an illusion created by the brain. “True” reality is then treated as the absolute spacetime filled with particles captured in the mathematics of Newton’s theory.

  The reason it relies on this premise is because by assigning objects perspective invariant properties, then they can continue to exist even if no other object is interacting with them, or, more specifically, they continue to exist even if “no one is looking at them.” For example, if you fire a cannonball from point A to point B, and you only observe it leaving point A and arriving at point B, Newtonian mechanics allows you to “track” its path between these two points even if you did not observe it.

  The problem is that you cannot do this in quantum mechanics. If you fire a photon from point A to point B, the theory simply disallows you from unambiguously filling in the “gaps” between the two points. People then declare that “realism is dead,” but this is a bit misleading because this is really only a problem for metaphysical/scientific realism. There are many other kinds of realism in literature.

  For example, the philosopher Jocelyn Benoist’s contextual realism argues that the exact opposite. The mathematical theory is not “true reality” but is instead a description of reality. A description of reality is not the same as reality. Would a description of the Eiffel Tower substitute actually seeing it in reality? Of course not, they’re not the same. Contextual realism instead argues that what is real is not the mathematical description but is precisely what we perceive. The reason we perceive reality in a way that depends upon perspective is because reality is just relative (or “contextual”). There is no “absolute” reality but only a contextual reality and that contextual reality we perceive directly as it really is.

  Thus for contextual realism, there is no issue with the fact that we cannot “track” things unambiguously, because it has no attachment to treating particles as if they persist as autonomous entities. It is perfectly fine with just treating it as if the particle hops from point A to point B according to some predictable laws and relative to the context in which the observer occupies. That is just how objective reality works. Observation isn’t important, and indeed, not even measurement, because whatever you observe in the experimental setting is just what reality is like in that context. The only thing that “arises” is your identification.

• ⁨Comment⁩ on ⁨The universe is bottle-necked at processor speed⁩ ⁨⁨9⁩ ⁨months⁩ ago⁩:

  Why did physicists start using the word “real” and “realism”? It’s a philosophical term, not a physical one, and it leads to a lot of confusion. “Local” has a clear physical meaning, “realism” gets confusing. I have seen some papers that use “realism” in a way that has a clear physical definition, such as one I came across defined it in terms of a hidden variable theory. Yet, I also saw a paper by coauthored by Anton Zeilinger that speaks of “local realism,” but very explicitly uses “realism” with its philosophical meaning, that there is an objective reality independent of the observer, which to me it is absurd to pretend that physics in any way calls this into account.

  If you read John Bell’s original paper “On the Einstein Podolsky Rosen Paradox,” he never once use the term “realism.” The only time I have seen “real” used at all in this early discourse is in the original EPR paper, but this was merely a “criterion” (meaning a minimum but not sufficient condition) for what would constitute a theory that is a complete description of reality. Einstein/Podolsky/Rosen in no way presented this as a definition of “reality” or a kind of “realism.”

  Indeed, even using the term “realism” on its own is ambiguous, as there are many kinds of “realisms” in the literature. The phrase “local realism” on its own is bound to lead to confusion, and it does, because I pointed out, even in the published literature physicists do not always use “realism” consistently. If you are going to talk about “realism,” you need to preface it to be clear what kind of realism you are specifically talking about.

  If the reason physicists started to talk about “realism” is because they specifically are referring to something that includes the EPR criterion, then they should call it “EPR realism” or something like that. Just saying “realism” is so absurdly ridiculous it is almost as if they are intentionally trying to cause confusion. I don’t really blame anyone who gets confused on this because like I said if you even read the literature there is no even consistent agreement on how to define it.

• ⁨Comment⁩ on ⁨Quantum⁩ ⁨⁨9⁩ ⁨months⁩ ago⁩:

  no that’s dialectics