tag:blogger.com,1999:blog-22973357.post3989257843531697274..comments2023-03-31T04:31:40.542-04:00Comments on Sabine Hossenfelder: Backreaction: Guest Post: “Undecidability, Uncomputability and the Unity of Physics. Part 2.” by Tim PalmerSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger71125tag:blogger.com,1999:blog-22973357.post-16647835285734647232020-03-02T11:45:04.547-05:002020-03-02T11:45:04.547-05:00I’m not sure I understand the implications of a SD...I’m not sure I understand the implications of a SD universe. <br /><br />In a recent comment, I traced the hypothetical path of a stable C12 atom from its nucleosynthesis within a long dead star, its travels through billions of years and like number miles across a sometimes highly turbulent and variable terrain, its various employments within the earth’s biosphere and finally, with it coming to Don Fosterhttps://www.blogger.com/profile/04814669413022486958noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53193283545067471902020-02-22T08:28:54.810-05:002020-02-22T08:28:54.810-05:00I read Palmer’s paper on the FQXi that makes a cle...I read Palmer’s paper on the FQXi that makes a clear point on using the Blum, Shub, and Smale (BSS) concept of computability [ https://en.wikipedia.org/wiki/Blum–Shub–Smale_machine ]. This is an odd concept for it involves complete computation of the reals to infinite precision and where our usual idea of close approximations are not real computations. This is a certain definition of Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56792264941208750412020-02-22T03:51:38.400-05:002020-02-22T03:51:38.400-05:00I agree that noncomputability may play a role unde...I agree that noncomputability may play a role underneath Quantum theory. I have read the paper for the essay contest and I have a question for Tim:<br />In page 8 you said that based on real computational processes in spacetime, a (uncomputable) deterministic local model can violate Bell's theorem without violating the freedom of choice assumption.<br />On the other hand, you also mentioned tytunghttps://www.blogger.com/profile/05777947785613061617noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12256229336930436042020-02-18T23:26:21.527-05:002020-02-18T23:26:21.527-05:00Don Foster wrote to me:
> I don’t know. As a fi...Don Foster wrote to me:<br />> I don’t know. As a first effort at addressing the possibility that the current mathematics of physics skews our sense of how the world works, it seems cogent and collegial.<br /><br />Well... my point was simply that since we already know the limited domain of applicability of classical physics, trying to fool around with classical physics is rather silly. PhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82824588951563370452020-02-18T23:16:26.723-05:002020-02-18T23:16:26.723-05:00Greg Feild wrote to me:
>Says the guy who reads...Greg Feild wrote to me:<br />>Says the guy who reads people's PhD theses.<br /><br />Says the guy who seems to think no one should ever read anyone's Ph.D. thesis.<br /><br />Which is sad.<br /><br />But predictable.PhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-3084891310493186722020-02-18T11:44:57.946-05:002020-02-18T11:44:57.946-05:00Reply PhysicistDave
Thanks very much for taking t...Reply PhysicistDave<br /><br />Thanks very much for taking time to reply. Clearly, I am not a physicist. My engagement here is more that of a humanitarian: I am concerned that people who believe in super determinism will experience a greater incident of accident in crossing the street!<br /><br />Perhaps your dismissal of the paper is justified. I know that an article about the paper on Phys.org Don Fosterhttps://www.blogger.com/profile/04814669413022486958noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-19214806521802189182020-02-18T08:49:36.073-05:002020-02-18T08:49:36.073-05:00>In short, some people have way too >much ti...>In short, some people have way too >much time on their hands!<br /><br />Says the guy who reads people's PhD theses.<br /><br />Your rants might be more coherent if you learned the meaning of words like "true", "model", "theory", etc.<br /><br />I'm just here to Poke the Parrot!<br />Greg Feildhttps://www.blogger.com/profile/11893021846714172269noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-17334022163824496612020-02-18T06:37:46.220-05:002020-02-18T06:37:46.220-05:00Don Foster asked:
>That possibility has been ar...Don Foster asked:<br />>That possibility has been argued in a recent paper: “Physics without Determinism: Alternative Interpretations of Classical Physics”...<br />>Is that argument sound?<br /><br />Well, I've read the paper, and to call it an "argument" is overly charitable. I'll be polite and say that the paper is "speculation," unwarranted speculation.<br />PhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-64693216675974669012020-02-18T05:57:36.546-05:002020-02-18T05:57:36.546-05:00This is parallel to the issue of computing recursi...This is parallel to the issue of computing recursively enumerable sets or languages. Quantum computing, entanglement, and theorem provers<br /><br />"We show that the class MIP* of languages that can be decided by a classical verifier interacting with multiple all-powerful quantum provers sharing entanglement is equal to the class RE of recursively enumerable languages."<br /><br />MIP*Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-15085127299099121332020-02-17T15:30:09.059-05:002020-02-17T15:30:09.059-05:00If you would, imagine a Disney cartoon that featur...If you would, imagine a Disney cartoon that features as protagonist a C12 atom and traces its path from its nucleosynthesis within a long dead star, its ejection into space at high velocity and its travels through space across billions of miles and like number years. It animates the atom's trajectory as it devolves into smaller orbits and eventually into the zigzag of Brownian motion in the Don Fosterhttps://www.blogger.com/profile/04814669413022486958noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-18852970271753531252020-02-17T14:27:32.320-05:002020-02-17T14:27:32.320-05:00Attractors may be the answer to the existence.Attractors may be the answer to the existence.Michael John Sarnowskihttps://www.blogger.com/profile/00528454593064091302noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-71828285631293535982020-02-17T09:30:35.996-05:002020-02-17T09:30:35.996-05:00Building the T-handle differently could affect the...Building the T-handle differently could affect the behaviour of the T-handle but the reason that the T-handle is moving in an unstable manner (or bistably) is because it is spinning about its intermediate-length axis. See https://en.wikipedia.org/wiki/Tennis_racket_theorem for a discussion of intermediate-axis spin; though the spinning T-handle in zero g shows the bistable/unstable motion much ben6993https://www.blogger.com/profile/11246990849377879772noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-91180712790888264922020-02-16T17:18:43.548-05:002020-02-16T17:18:43.548-05:00My friend, you are very connected with the realism...<br />My friend, you are very connected with the realism and locality of Einstein; I don't know why Einstein saw the behavior of the pair of quantum particles spooky, when you can do classical experiments where the same rarity happens and nobody is astonished at the resultLuishttps://www.blogger.com/profile/05491803947570764962noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-20038710059565698822020-02-16T11:45:21.620-05:002020-02-16T11:45:21.620-05:00I am not that experienced with fractional operator...I am not that experienced with fractional operators, though I have read on them a bit. My email is at <br /><br />goldenfieldquaternions@gmail.com<br /><br />I have just had this idea for a while on how for ultrashort pulses of light that the ergodic assumption should breakdown. I have thought there might be some new types of physics or new forms of quantum states in this regime.Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-75918649501342240272020-02-15T07:17:00.222-05:002020-02-15T07:17:00.222-05:00Lawrence,
I am afraid your comment fails to do ju...Lawrence,<br /><br />I am afraid your comment fails to do justice to fractional calculus, in general, and fractional dynamics, in particular.<br /><br />This is a rich field of research with lots of subtleties and ramifications into chaos and complexity theories. We can barely skim the surface here and that's why the discussion should continue elsewhere. Ervin Goldfainhttps://www.blogger.com/profile/07585008304556273617noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53337115844403227042020-02-14T18:09:58.546-05:002020-02-14T18:09:58.546-05:00Bourbaki wrote:
>This summarizes in the followi...Bourbaki wrote:<br />>This summarizes in the following way: QM is a black box. It works. It explains a lot (at least QFT does). But. And its a big BUT, we have no tools to open that box. There is no hidden physical interpretation inside QM.<br /><br />Bohmian mechanics works: Bohm showed how to apply it to QFT way back in his second paper in 1952.<br /><br />It's not pretty but it works, PhysicistDavehttps://www.blogger.com/profile/11111405959451703182noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-67579970142985104952020-02-14T14:13:49.631-05:002020-02-14T14:13:49.631-05:00@Ervin, Bourbaki complained I wrote measurable. I ...@Ervin, Bourbaki complained I wrote measurable. I mistyped here. Elsewhere I wrote immeasurable. <br /><br />The fractional calculus can reflect a utility function or momentum renormalization function that is d(p,α) = (p^(1-α} – 1)/(1 – α), that for α = 0 gives a linear expression and as α → 1 this is logarithmic. The linear expression would correspond to the standard ergodic case. In between theLawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-80477143946899472682020-02-14T13:40:59.793-05:002020-02-14T13:40:59.793-05:00I think the origin of spinning and flipping is in ...I think the origin of spinning and flipping is in the fact that matter structure cannot be absolutely rigid. Fluctuations of tension swing the nutation axis over 180 degree to the next relaxation of tension waves by coherent interference with each others.<br /><br />Build the T-handle from the mix of different molecule structure and see how its behavior changes...Eusahttps://www.blogger.com/profile/14114706429392111062noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-23704880874675625022020-02-14T06:31:31.895-05:002020-02-14T06:31:31.895-05:00I hope this video passes the moderator as it seems...I hope this video passes the moderator as it seems to be relevant:<br />https://www.youtube.com/watch?v=1n-HMSCDYtM&feature=youtu.be<br /><br />It shows a video of a T-shaped handle in zero gravity in a bi-stable state due to intermediate moments of inertia. The handle spins and flips backwards and forwards regularly along an axis. The handle's motion reminds me of Tim's diagram of ben6993https://www.blogger.com/profile/11246990849377879772noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-89559449358178713852020-02-14T05:42:24.564-05:002020-02-14T05:42:24.564-05:00You are right. A fractal attractor seems to be th...You are right. A fractal attractor seems to be the last straw to save locality and determinism <b>and</b> avoid the consequences of Bell's theorem. Of all attempts at making sense of Quantum Theory I find this one the least intelligible.Wernerhttps://www.blogger.com/profile/08502954437062856468noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-24545843283963570962020-02-13T20:03:01.246-05:002020-02-13T20:03:01.246-05:00Randomness is undefinable. If there were a way of ...Randomness is undefinable. If there were a way of codifying random sequences they could be compressed by some algorithm. Chaitin's halting probability makes some light on this.<br /><br />While there is decoherence and the rest, this just reduces a density matrix to a diagonal with probabilities. It does not tell us which outcome will be found. The observed eigenvalue is then something Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-43440870423071323642020-02-13T16:20:36.081-05:002020-02-13T16:20:36.081-05:00Correction: I misread Braverman, and he does not a...Correction: I misread Braverman, and he does not actually show that the Halting Problem is BSS-decidable. However, here is a proof. Note that the infinite-precision arithmetic operations and comparisons allowed by the BSS model allow one to extract arbitrary bits from the binary expansion of a real number. Note also that you can use arbitrary real constants in your program, including real Kevin S. Van Hornhttps://www.blogger.com/profile/07591228017757297031noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-68623514798306444032020-02-13T15:04:46.607-05:002020-02-13T15:04:46.607-05:00Here's me touching yet another part of the ele...Here's me touching yet another part of the elephant (not sure if it's the elephant in the room though, to mix metaphors).<br /><br />Navier-Stokes is one of the Millennium Problems. Which is fine for the ocean under Europa's icy crust, and the tiny droplet which carries the virus which gives you Covid-19.<br /><br />But the universe is not "turtles all the way down" (or up) JeanTatehttps://www.blogger.com/profile/08737430572613792118noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-72808999470847171122020-02-13T13:57:22.542-05:002020-02-13T13:57:22.542-05:00@Bourbaki, I said immesuarable.
The discussion on...@Bourbaki, I said immesuarable.<br /><br />The discussion on Banach-Tarski is a separate topic. Sorry for the confusion.Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-48956482606872720412020-02-13T12:48:09.013-05:002020-02-13T12:48:09.013-05:00Cubitt and others posted proofs of the undecidabil...Cubitt and others posted proofs of the undecidability of the spectral band gap and of phase diagrams in arXiv:1810.01858 and arXiv:1910.01631. Does this count as a problem of decidability in the mathematical and logical sense, in theoretical physics? If not, why not?Michael Goginshttps://www.blogger.com/profile/07300917064580760923noreply@blogger.com