Not signed in (Sign In)

Not signed in

Want to take part in these discussions? Sign in if you have an account, or apply for one below

  • Sign in using OpenID

Site Tag Cloud

2-category 2-category-theory abelian-categories adjoint algebra algebraic algebraic-geometry algebraic-topology analysis analytic-geometry arithmetic arithmetic-geometry book bundles calculus categorical categories category category-theory chern-weil-theory cohesion cohesive-homotopy-type-theory cohomology colimits combinatorics complex complex-geometry computable-mathematics computer-science constructive cosmology deformation-theory descent diagrams differential differential-cohomology differential-equations differential-geometry digraphs duality elliptic-cohomology enriched fibration foundation foundations functional-analysis functor gauge-theory gebra geometric-quantization geometry graph graphs gravity grothendieck group group-theory harmonic-analysis higher higher-algebra higher-category-theory higher-differential-geometry higher-geometry higher-lie-theory higher-topos-theory homological homological-algebra homotopy homotopy-theory homotopy-type-theory index-theory integration integration-theory internal-categories k-theory lie-theory limits linear linear-algebra locale localization logic mathematics measure measure-theory modal modal-logic model model-category-theory monad monads monoidal monoidal-category-theory morphism motives motivic-cohomology nlab noncommutative noncommutative-geometry number-theory of operads operator operator-algebra order-theory pages pasting philosophy physics pro-object probability probability-theory quantization quantum quantum-field quantum-field-theory quantum-mechanics quantum-physics quantum-theory question representation representation-theory riemannian-geometry scheme schemes set set-theory sheaf simplicial space spin-geometry stable-homotopy-theory stack string string-theory superalgebra supergeometry svg symplectic-geometry synthetic-differential-geometry terminology theory topology topos topos-theory tqft type type-theory universal variational-calculus

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to nForum
If you want to take part in these discussions either sign in now (if you have an account), apply for one now (if you don't).
    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeSep 18th 2014
    • (edited Sep 18th 2014)

    Here a simple observation which I find somewhat entertaining. I have created the links below as nLab entries in as far as they had been missing.


    An old abandoned physical theory – often mentioned, these days, as a warning example – is the idea of Lord Kelvin that elementary matter particles are fundamentally just vortices in some spacetime-filling fluid-like substance

    http://ncatlab.org/nlab/show/On+Vortex+Atoms .

    It is however striking that the modern concept of baryogenesis

    http://ncatlab.org/nlab/show/baryogenesis

    via the chiral anomaly

    http://ncatlab.org/nlab/show/chiral+anomaly

    and its sensitivity to instantons

    http://ncatlab.org/nlab/show/instanton

    is not too far away from Kelvin’s intuition.

    To play this out in the most pronounced scenario, consider, for the sake of it, a “Hartle-Hawking cosmology” spacetime

    http://ncatlab.org/nlab/show/no+boundary+proposal

    carrying N Yang-Mills instantons. An instanton is in a precise sense the modern higher dimensional and gauge theoretic version of what Kelvin knew as a fluid vortex.

    Then the non-conservation law of the baryon current due to the chiral anomaly says precisely the following: the net baryon number in the early universe is a monotonically increasing number – that’s the baryogenesis bit – such that as we approach the late time after the “big bang” this number converges onto the integer N, the number of instantons.

    Hence while in the modern picture of baryogenesis via gauge anomaly an elementary particle is not identified with an instanton, nevertheless each instanton induces precisely one net baryon.

    (If you don’t want to consider this on a Hartle-Hawking-type Euclidean no-boundary spacetime but on globally hyperbolic spacetime this conclusion still holds just not relative to 0 baryon number at the “south pole” of the cosmic 4-spehere, but relative to the net baryon number at any chosen spatial reference slice. )

    • CommentRowNumber2.
    • CommentAuthorUrs
    • CommentTimeSep 18th 2014

    I have put this as a comment into On Vortex Atoms.

    • CommentRowNumber3.
    • CommentAuthorRodMcGuire
    • CommentTimeSep 18th 2014

    Doesn’t this notion of vortex atoms stem from Descartes (without him being acknowledged because his theories didn’t work)? Basically that all bodies and so-called atoms were fluid vortices.

    Routledge - Descartes - Physics and mathematics

    Descartes also rejected atoms and the void, the two central doctrines of the atomists, an ancient school of philosophy whose revival by Gassendi and others constituted a major rival among contemporary mechanists. Because there can be no extension without an extended substance, namely body, there can be no space without body, Descartes argued. His world was a plenum, and all motion must ultimately be circular, since one body must give way to another in order for there to be a place for it to enter ( Principles II: §§2–19, 33). Against atoms, he argued that extension is by its nature indefinitely divisible: no piece of matter in its nature indivisible ( Principles II: §20). Yet he agreed that, since bodies are simply matter, the apparent diversity between them must be explicable in terms of the size, shape and motion of the small parts that make them ( Principles II: §§23, 64) (see Leibniz, G.W. §4 ).

    • CommentRowNumber4.
    • CommentAuthorUrs
    • CommentTimeSep 18th 2014

    Thanks, that’s nice. I have added it to the entry, here.

    • CommentRowNumber5.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 18th 2014

    As mentioned here, I wrote a chapter once on Kelvin and Tait’s knotted vertices.

    • CommentRowNumber6.
    • CommentAuthorUrs
    • CommentTimeSep 18th 2014

    Thanks for that, too. Have added the pointer here.

    • CommentRowNumber7.
    • CommentAuthorRodMcGuire
    • CommentTimeSep 18th 2014

    As mentioned here, I wrote a chapter once on Kelvin and Tait’s knotted vertices.

    Your chapter discusses that Tait and Kelvin were keen to bring God into science/math.

    They were probably familiar with Descartes’ religious writings and his vortex theory of matter but since (I think) its main application, to explain gravity, failed they really couldn’t mention it while if they succeeded they would have beat Descartes at his own game.

    • CommentRowNumber8.
    • CommentAuthorTodd_Trimble
    • CommentTimeSep 19th 2014

    To David Corfield: I’m reading with interest your chapter on knots. But I’m having trouble with some minor points: there was no President McKinsey. There was a President McKinley, but I don’t think his administration fits the time frame of the recent laying of the transatlantic cable. From what I can make out, the pleasantries might have been between Queen Victoria and President Buchanan.

    • CommentRowNumber9.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 19th 2014
    • (edited Sep 19th 2014)

    Todd, you’re quite right. According to Wikipedia, it took place on August 16, 1858. The chapter was intended many years ago to be the first in a popular book on knots. I can’t begin to recall why I mistook the president.

    Rodd, I’ve no reason to think Descartes would be a particular point of reference for them. In the early 18th century, there was great pride that a protestant Briton had gone so much further than a catholic Frenchman. Newton certainly played up the differences, after early admiration for Descartes. The famous Hypotheses non fingo is part of his distinguishing himself from the rationalist continentals:

    I have not as yet been able to discover the reason for these properties of gravity from phenomena, and I do not feign hypotheses. For whatever is not deduced from the phenomena must be called a hypothesis; and hypotheses, whether metaphysical or physical, or based on occult qualities, or mechanical, have no place in experimental philosophy. In this philosophy particular propositions are inferred from the phenomena, and afterwards rendered general by induction.

    This was cited approvingly by William Whewell, a very prominent methodologist in the first half of the 19th century.

    Also, the key to Kelvin and Tait’s model was the stability induced by rapid spinning about the meridians. I don’t believe Descartes had any such notion.

    • CommentRowNumber10.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 19th 2014

    It says

    As a literal theory of physics the vortex atom hypothesis was soon rejected.

    I have a recollection that it was surprisingly long-lived (20 years?). I guess it all depends on what’s meant by ’soon’.

    • CommentRowNumber11.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 19th 2014

    From the interesting paper (added as reference), Helge Kragh, 2002, The Vortex Atom: A Victorian Theory of Everything,Volume 44, Issue 1-2, pp. 32–114

    The vortex atom theory has often been seen as part of a Cartesian tradition in European thought, which is justified in a general sense but not when it comes to details. In spite of the similarities, there are marked differences between the Victorian theory and Descartes’s conception of matter. Thus, although Descartes’s plenum was indefinitely divisible, his ethereal vortices nonetheless consisted of tiny particles in whirling motion. It was non-atomistic, yet particulate. Moreover, the French philosopher assumed three different species of matter, corresponding to emission, transmission, and reflection of light (luminous, ‘‘subtle’’, and material particles). The vortex theory, on the other hand, was strictly a unitary continuum theory. (p. 33)

    As for duration,

    As a theory with a fairly definite life-time, from 1867 to about 1898,…

    although,

    At about 1890, the theory had run out of steam and was abandoned by most researchers, including its founder William Thomson. (p. 34)

    • CommentRowNumber12.
    • CommentAuthorUrs
    • CommentTimeSep 19th 2014

    David, you clearly know much more about the history of this idea than I do, please add it to the entry as appropriate. (myself, am quasi-offline for the moment)

    • CommentRowNumber13.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 19th 2014

    I did already.