Cartoon aided design: The lighter side of computing

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John B #5 and Roy Badami #19: I think linking to the top of Shtetl-Optimized is correct. The blog almost always talks about quantum computing, and the misconceptions about how quantum computing come up so often that it’s even in the tagline and the previous tagline. I wonder what the Kolmogorov complexity size of that QM description would be, not including the seed? Anytime the simulation needs to simulate a random event, it would just use the next digit in PI (or any other pseudo-random sequence). I think that it is not the preferred basis which is primarily problematic with ppnl #66’s model. (Problematic, in the sense, what makes it unlike the actual QM.)

Yes, entanglement is not a requirement of instantaneous action at a distance (IAD). IAD in QM (as in classical diffusion) comes about only because the Fourier theory itself has IAD built into it. And the Fourier theory comes in because measurements involve eigenstates. Well, not specifically of the amplitudes being complex—almost every phenomenon in QM would still be there with positive and negative real amplitudes—but of the basic structure of QM, involving linearly-evolving amplitudes whose 2-norm is conserved, I claim yes. That there is no mechanism (for what? I take it for randomness) is what Born might have said—and I am not sure if he really actually said that. Bohr could easily have said it, also Heisenberg. But Born? I am not sure. In particular, notice the words: “if,”“would,”“certain,”“similarities” etc. (Is skipping such words the reason you have difficulty understanding what I write? Were you very rapidly browsing what I wrote?) I often have trouble understanding what you are saying. When I do think I understand it seems wrong in strange ways. For example:Regardless of whether this tensor-network quantum state-space postulate is Platonically true, for a great many quantum engineering purposes it is effectively true, and this is is one strong motivation (among several) for the present-day flourishing of the literature on tensor-network state-spaces. This Occam-compatible postulate explains, naturally and even (arguably) very beautifully, why present-day experiments and simulations alike readily exhibit low-dimension spukhafte Fernwirkungen (like photon interference), but exhibit high-dimension spukhafte Fernwirkungen (like scalable quantum computation) only with very great difficulty such demonstrations perhaps being impossible even principle (as Kalai’s preprints argue).

Entanglement is just something that unavoidably pops out when you have superposition and also a tensor product structure on your Hilbert space. It doesn’t need to be added as a separate axiom. And yes, things like the Bell inequality can be explicitly understood as interference effects. QM needs Complex Numbers but they might have a more complex or a simpler way for working with them. We are accustomed to working with a+bi form or some other equivalent form but they might be using pulses of electricity or be more comfortable with some matrix notation….. So the phrase “Damned with faint praise” ( https://en.wikipedia.org/wiki/Damning_with_faint_praise) came to mind when I read Dr Motl’s post.But in no case would I allow you to simply observe—though publicly—that you find me difficult to understand, and let the matter explicitly stop just at that. There can be implicit bad effects out of this practice, and I am concerned about them. People who do know a lot but think QC can do LOTS more than it can (or at least can now). I think this set was larger at one time then it is now.

For people who, willfully or not, misunderstand my work and are open to reforming their ways I have a list of references of increasing mathematical precision that I send to help set them straight. This has now become first on that list. won’t interest me, I am sure. The application would be of interest to information theory/TCS folks, but it is not, to me. My interests are mainly in the QM foundations and then, may be, some software simulations of some basic QM phenomena and/or applications to some topic here and there, may be, from condensed matter physics (i.e., if at all).Nuclear magnetic resonance spectroscopy is one of the few remaining areas of physical chemistry for which polynomially scaling quantum mechanical simulation methods have not so far been available. In this communication [we simulate] a protein containing over a thousand nuclear spins… fred #90: Yes, of course. But Bell’s Theorem tells us that such a simulation of our universe on a classical digital computer would necessarily be a nonlocal one (that is, the simulation would involve rapid signalling between memory cells corresponding to faraway events, violating the causal structure of the spacetime, even if we, living inside the universe, never actually experienced such signalling). People who don’t know a lot but think QC can do LOTS more than it can (or at least can now). The boy in your strip. It’s true that technically, the program would need a random number generator to make the final selection of a measurement outcome, and have it “really” be random (rather than pseudorandom). But I’ve never seen that as such a big deal—as a challenge to the Church-Turing Thesis or whatever—because even a deterministic program can easily output a list of probabilities, so that the only thing left for you to do would be to “spin the wheel.” This comic is exactly where we should be going with our children, we should help children explore quantum computing at their own pace. Far too often these days the media pressurizes children into performing their first superposition at too young an age, most are not ready for it.