Slate Article

3 Responses to Slate Article

1. D R Lunsford says:

   July 9, 2004 at 2:33 pm

   Urs, your comment is that of the apologist.

   It’s perfectly possible to give non-equation explanations that hang together of real physics. It can’t be done for strings because there is nothing to really describe.
2. Urs Schreiber says:

   July 9, 2004 at 5:40 am

   Semiclassical elegance

   Popular descriptions of sciences which involve lots of math are always problematic. An infinity of analogies does not capture the content of an equation. It’s indeed very much like talking about Beethoven’s music without ever listening to it. You will never get the idea, no matter how many words you read about it.

   One thing is this common statement that ‘all particles would be vibration modes of string’. While not fully wrong, this completely misses the point that the interesting thing about the superstring’s spectrum is its massless part, where there is essentially no vibration at all!

   There is however sort of a ‘supervibration’ since the fermionic worldhseet modes are excited. The nature of the massless spectrum is in fact much better understood in terms of representation theory, very much as for point particles.

   I once tried to give a semi-popular description of how the superstring’s spectrum really arises, trying to improve on the ‘particles are violin string notes’-statement.

   If one is really interested in the pedagogy of string theory, i.e. in finding better ways to get this abstract formal entity into semi-laymen’s brains, then I would rather recommend for instance the ‘Geometric Algebra‘ approach, as a neat notational framework to fill all kinds of spinor constructions with life. For instance I claim that the world sheet spin fields that generate the Ramond-sector states of string, and hence the target space fermions, are nothing but slightly souped up ‘rotors’ that they are so very fond of in Hestenes’ school of thinking about spin geometry.

   (As you all know and appreciate, every good idea is part of string theory – and rotors are a good idea. 😉

   By the way, in the slate article that Peter mentioned it says:

   Greene plays fast and loose with terms like beauty and elegance, using them in a semiclassical, semiromantic sense

   Heh, I like that: ‘Semiclassical elegance’! 🙂 If we could just fully quantize elegance Brian Greene might after all be able to prove that string theory is quantum-elegant. There might be quantum corrections to that, but I suspect most of the string’s elegance is protected by supersymmetry or is dual to its romaticism.

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