Re: Critique of Lubos Motl's opinions on Loop Quantum Gravity

thomas_larsson...@xxxxxxxxxxx wrote:
> Suresh Maran skrev:
> >
> > Your research on application of loop quantum gravity to harmonic
> > oscillator is of purely mathematical significance apply. You cannot
> > simply apply a theory to something else, out of its conceptual
> > framework. For example it does *not* make sense to apply 'string
> > theory' to understand 'dancing' or 'fishing' or 'skydiving' etc.
> >
>
> New methods become respectable by first showing that they reproduce
> the correct results for well-understood problems. This is e.g. how
> Feynman overcame the resistence against path integrals of Niels Bohr
> and others. That LQG methods fail to reproduce the oscillator
> spectrum is quite remarkable, and this fact deserves to be as well
> known as the fact that string theory is not background independent.
>
> Btw, I am not a string theorist, cf.
> http://www.arxiv.org/abs/math-ph/0103013 .

But is the harmonic oscillator well understood? From Tony Smith's
website:

Predrag Cvitanovic has written a web book on Group Theory... in the
Epilogue of his web book on Group Theory: "... once I learned that
chaos is generic for generic Hamiltonian flows, I lost faith in doing
field theory by pretending that it is a bunch of harmonic oscillators,
with interactions accounted for as perturbative corrections. This
picture is simply wrong - strongly coupled field theories
(hydrodynamics, QCD, gravity) are nothing like that ... So they
excommunicated me from the ranks of high energy theorists, and now ...
we are working out quantum chaos ... this is ... replace the path
integral with a fractal set of semi-classical orbits. ...".

.