gjm asserts "Of the various ways to understand the quantum mechanics involved in the Standard Model, the clear winner is "many worlds"
LOL ... by that lenient standard, the first racehorse out of the gate, or the first sprinter out of the blocks, can reasonably be proclaimed "the clear winner" ... before the race is even finished!
That's a rational announcement only for very short races. Surely there is very little evidence that the course that finishes at comprehensive understanding of Nature's dynamics ... is a short course?
A...
gjm avers: 'When Eliezer says that QM is "non-mysterious' ... He's arguing against a particular sort of mysterianism"
That may or may not be the case, but there is zero doubt that this assertion provides rhetorical foundations for the essay And the Winner is... Many-Worlds!.
A valuable service of the mathematical literature relating to geometric mechanics is that it instills a prudent humility regarding assertions like "the Winner is... Many-Worlds!" A celebrated meditation of Alexander Grothendieck expresses this humility:
..."
gjm avers "Landsberg that has a section headed "Clash of cultures" but it could not by any reasonable stretch be called an essay. It's only a few paragraphs long."
LOL ... gjm, you must really dislike Lincoln's ultra-short Gettysburg Address!
More seriously, isn't the key question whether Landsberg's essay is correct to assert that "there are language and even philosophical barriers to be overcome", in communicating modern geometric insights to STEM researchers trained in older mathematical techniques?
Most seriously of all,...
Edit 1: Kudos to "gjm" (see above) for pointing to Spivak's page on Amazon!
Edit 2: Spivak's Hogwarts proof implicitly uses a fundamental theorem in differential geometry that is called Cartan's Magic Formula ... this oblique magical reference is Spivak's joke ... as with many magical formulas, the origins of Cartan's formula are obscure.
...Regrettably, tgb, even the redoubtable Google Books does not provide page-images for Spivak's Physics for Mathematicians: Mechanics I. The best advice I can give is to seek this book within a university library
LOL --- perhaps a chief objective of the Ministry of Magic is to conceive and require obfuscating interfaces to magic! That would explain a lot!
Parallels to real-world high-school and/or undergraduate mathematical education ... are left as an exercise. :)
For a professional-grade comment on "muggle math" versus "Hogwarts math", see Michael Spivak's Physics for Mathematicians: Mechanics I.
To express this point another way ... how likely is it, that Harry's final understanding of magic will be non-mathematical? What grade of mathematical abstraction capabilities will Harry need to acquire?
Conspicuously absent from the canon, and from Methods of Rationality (so far) --- and absent entirely from the Hogwarts curriculum --- are two fundamental elements of rational cognition:
Therefore
...Postulate 1 "Magic" is the name that witches, wizards, and muggles alike give to the practice of manipulating physical reality by negotiation with agents that are (artificial? primordial? evolved? accidentally created?) intelligences.
Postulate 2 "Magical Spells" is the name that witches, wiza
An elaboration of the above argument now appears on Shtetl Optimized, essentially as a meditation on the question: What strictly mathematical proposition would comprise rationally convincing evidence that the key linear-quantum postulates of "One Ghost in the Quantum Turing Machine* amount to “an unredeemed claim [that has] become a roadblock rather than an inspiration” (to borrow an apt phrase from Jaffe and Quinn's arXiv:math/9307227).
Readers of Not Even Wrong seeking further (strictly mathematical) mathematical illumination in regard to these issue...
Shminux, it may be that you will find that your concerns are substantially addressed by Joshua Landsberg's Clash of Cultures essay (2012), which is cited above.
"These conversations [are] very stressful to all involved ... there are language and even philosophical barriers to be overcome."
The entanglement(s) of hot-noisy-evolved biological cognition with abstract ideals of cognition that Eliezer Yudkowsky vividly describes in Harry Potter and the Methods of Rationality, and the quantum entanglement(s) of dynamical flow with the physical processes of cognition that Scott Aaronson vividly describes in Ghost in the Quantum Turing Machine, both find further mathematical/social/philosophical echoes in Joshua Landsberg's Tensors: Geometry and Applications (2012), specifically in Landsberg's thought-provoking introductory section Section 0.3: Clas...
Quantum aficionados in the mold of Eliezer Yudkowsky will have fun looking up "Noether's Theorem" in the index to Michael Spivak's well-regarded Physics for Mathematicians: Mechanics I, because near to it we notice an irresistible index entry "Muggles, 576", which turns out to be a link to:
Theorem The flow of any Hamiltonian vector field consists of canonical transformations
Proof (Hogwarts version) ...
Proof (Muggles version) ...
Remark It is striking that Dirac's The Principles of Quantum Mechanics (1930), Feynman's Lectures on ...
Shminux, perhaps some Less Wrong readers will enjoy the larger reflection of our differing perspectives that is provided by Arthur Jaffe and Frank Quinn’s ‘Theoretical mathematics’: Toward a cultural synthesis of mathematics and theoretical physics (Bull. AMS 1993, arXiv:math/9307227, 188 citations); an article that was notable for its biting criticism of Bill Thurston's geometrization program.
Thurston's gentle, thoughtful, and scrupulously polite response On proof and progress in mathematics (Bull. AMS 1994, arXiv:math/9307227, 389 citations) has emerged ...
Thank you for your gracious remarks, Paper-Machine. Please let me add, that few (or possibly none) of the math/physics themes of the preceding posts are original to me (that's why I give so many references!)
Students of quantum history will find pulled-back/non-linear metric and symplectic quantum dynamical flows discussed as far back as Paul Dirac's seminal Note on exchange phenomena in the Thomas atom (1930); a free-as-in-freedom review of the nonlinear quantum dynamical frameworks that came from Dirac's work (nowadays called the "Dirac-Frenkel-M...
Shminux, there are plenty of writers---mostly far more skilled than me!---who have attempted to connect our physical understanding of dynamics to our mathematical understanding of dynamical flows. So please don't let my turgid expository style needlessly deter you from reading this literature!
In this regard, Michael Spivak's works are widely acclaimed; in particular his early gem Calculus on Manifolds: a Modern Approach to Classical Theorems of Advanced Calculus (1965) and his recent tome Physics for Mathematicians: Mechanics I (2010) (and in a comment on...
Gjm asks "Along what vector field V are you taking the Lie derivative?
The natural answer is, along a Hamiltonian vector field. Now you have all the pieces needed to ask (and even answer!) a broad class of questions like the following:
Alice possesses a computer of exponentially large memory and clock speed, upon which she unravels the Hilbert-space trajectories that are associated to the overall structure ), where
is a Hilbert-space (considered as a manifold),
is its metric,
is its symplectic form,
is the complex structure induced by
), and
)
JLM, the mathematically natural answer to your questions is:
• the quantum dynamical framework of (say) Abhay Ashtekar and Troy Schilling's Geometrical Formulation of Quantum Mechanics arXiv:gr-qc/9706069v1, and
• the quantum measurement framework of (say) Carlton Caves' on-line notes Completely positive maps, positive maps, and the Lindblad form, both pullback naturally onto
• the varietal frameworks of (say) Joseph Landsberg's Tensors: Geometry and Applications
Textbooks like Andrei Moroianu's Lectures on Kahler Geometry and Mikio Nakahara's Geometry, Topolo...
The dynamicist Vladimir Arnold had a wonderful saying:
"Every mathematician knows that it is impossible to understand any elementary course in thermodynamics."
This saying is doubly true of quantum mechanics. For example, the undergraduate quantum physics notion of "multiply a quantum vector by " is not so easy to convey without mentioning the number "
." Here's how the trick is accomplished. We regard Hilbert space as a real manifold
that is equipped with a symplectic form
and a metric
. Given an (arbitrary) vector fi...
Thank you gjm. To the best of my understanding, (1) all markup glitches are fixed; (2) all links are live; and (3) an added paragraph (fourth-from-last) now explicitly links dynamic-J methods to Scott's notion of "freebits".
Gjm, after a round-of-suffering with the LaTeX equation editor, any-and-all markup glitches in the above comment now seem to be fixed (at least, the comment now parses OK on FireFox/OSX and Safari/OSX). Please let me know if you are encountering any remaining markup-relating problems, and if so, I will attempt to fix them.
Rancor commonly arises when STEM discussions in general, and discussions of quantum mechanics in particular, focus upon personal beliefs and/or personal aesthetic sensibilities, as contrasted with verifiable mathematical arguments and/or experimental evidence and/or practical applications.
In this regard, a pertinent quotation is the self-proclaimed "personal belief" that Scott asserts on page 46:
..."One obvious way to enforce a macro/micro distinction would be via a dynamical collapse theory. ... I personally cannot believe that Nature would
Rancor commonly arises when STEM discussions in general, and discussions of quantum mechanics in particular, focus upon personal beliefs and/or personal aesthetic sensibilities, as contrasted with verifiable mathematical arguments and/or experimental evidence and/or practical applications.
In this regard, a pertinent quotation is the self-proclaimed "personal belief" that Scott asserts on page 46:
..."One obvious way to enforce a macro/micro distinction would be via a dynamical collapse theory. ... I personally cannot believe that Nature would
A preprint would be terrific too.
A tough(?) question and a tougher(?) question: When self-modifying AI's are citizens of Terry Tao's Island of the Blue-Eyed People/AIs, can the AIs trust one another to keep the customs of the Island? On this same AI-island, when the AI's play the Newcomb's Paradox Game, according to the rules of balanced advantage, can the PredictorAIs outwit the ChooserAIs, and still satisfy the island's ProctorAIs?
Questions in this class are tough (as they seem to me), and it is good to see that they are being creatively formalized.