Recent content by aro

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    Accuracy of timing in sports (Olympic Games)

    Previous link shows Omega's implementation. But, here is a photo of the position of the speakers: https://twitter.com/robbertderijk/status/435021551809732608 Distance difference to athlete seems to be approximately the width of the lane, i.e. 3m or 0.01s. IMO, if you want to use advanced...
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    Accuracy of timing in sports (Olympic Games)

    http://www.omegawatches.com/press/press-release-detail/2232
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    Graduate Ising model, same interaction with all spins

    There are systems that behave approximately in this way: Consider a localized (e.g. bound to a defect) electron in a solid whose wavefunction stretches out over many lattice sites. Assume each nucleus (lattice site) has nonzero spin. Now each nuclear spin couples to the spin of the electron (by...
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    Accuracy of timing in sports (Olympic Games)

    Hello all, If you have been watching the olympic games lately you could have seen that in the past week it has occurred twice that an athlete won (and another lost) a gold medal by a time difference of a few 1000th of a second. Both occurrences where in speed skating (i.e. the 500m and 1500m...
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    Graduate Is spacetime a physical entity?

    Regarding vacuum and virtual particles: Since Einstein put forward the possibility of converting energy into praticles and vice versa (providing all relevant conservation laws are obeyed) the old concept of 'billiard ball'-like particles became insufficient. There had to be a construct that...
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    Graduate Local symmetry and forces, what book to read?

    I would like some tips about what book I should read if I want to properly understand the relation between local symmetry and forces in gauge theories. And with properly uinderstand I mean a combination of mathematics and intuition/visualization. On the topic of QFT I have the books by Zee (...
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    Graduate Near-to-far field tranformation

    I would recommend Principles of Nano-Optics, by Novotny and Hecht. I'll try to give an explanation to give you at least an idea of how it works: In near field optical microscopy a probe of subwavelenth dimensions (which usually can be modeled as a dipole) is placed in very close proximity...
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    Graduate Numerical evaluation of Sommerfeld Integral

    In EM scattering problems in inhomogeneous (layered) media one may encounter Sommerfeld integrals of the form: \int_{0}^{\infty}J_{n}(k_{\rho},\rho)k_{\rho}^{n+1}G(k_{\rho})dk_{\rho} where J is a Bessel function and G is a spectral Green's function, \rho is source-observer distance and in...