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Cake day: June 27th, 2023

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  • blakestacey@awful.systemstoTechTakes@awful.systemsruh roh
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    8 hours ago

    Please don’t make posts to TechTakes that are just bare images without a description. The description can be simple, like “Screenshot from YouTube saying ‘Ad blockers violate YouTube’s Terms of Service’”. Some of our participants rely upon screenreaders. Or are crotchety old people who remember an Internet that wasn’t all three websites sharing snapshots of the other two websites.










  • There’s a whole lot of assuming-the-conclusion in advocacy for many-worlds interpretations — sometimes from philosophers, and all the time from Yuddites online. If you make a whole bunch of tacit assumptions, starting with those about how mathematics relates to physical reality, you end up in MWI country. And if you make sure your assumptions stay tacit, you can act like an MWI is the only answer, and everyone else is being un-mutual irrational.

    (I use the plural interpretations here because there’s not just one flavor of MWIce cream. The people who take it seriously have been arguing amongst one another about how to make it work for half a century now. What does it mean for one event to be more probable than another if all events always happen? When is one “world” distinct from another? The arguments iterate like the construction of a fractal curve.)




  • “Quantum computation happens in parallel worlds simultaneously” is a lazy take trotted out by people who want to believe in parallel worlds. It is a bad mental image, because it gives the misleading impression that a quantum computer could speed up anything. But all the indications from the actual math are that quantum computers would be better at some tasks than at others. (If you want to use the names that CS people have invented for complexity classes, this imagery would lead you to think that quantum computers could whack any problem in EXPSPACE. But the actual complexity class for “problems efficiently solvable on a quantum computer”, BQP, is known to be contained in PSPACE, which is strictly smaller than EXPSPACE.) It also completely obscures the very important point that some tasks look like they’d need a quantum computer — the program is written in quantum circuit language and all that — but a classical computer can actually do the job efficiently. Accepting the goofy pop-science/science-fiction imagery as truth would mean you’d never imagine the Gottesman–Knill theorem could be true.

    To quote a paper by Andy Steane, one of the early contributors to quantum error correction:

    The answer to the question ‘where does a quantum computer manage to perform its amazing computations?’ is, we conclude, ‘in the region of spacetime occupied by the quantum computer’.





  • TBH, I ignore her physics takes too. Her background is in the cosmology/quantum gravity corner of the subject. That’s a different specialization from the experimental implementation of quantum computers. And when she wandered into quantum foundations, a subject I’ve put a lot of work into understanding, her thinking came across as in part shallow, in part deliberately contrarian. So, yeah, Google is hyping their work — that’s a safe bet — and further progress is going to be harder than the sales talk makes it sound. But on the other hand, it’s possible to have “physicist disease” about other subfields of physics than one’s own.

    (I have not had the time and energy to read the underlying paper in detail myself yet.)