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Paulibus
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Soon, I believe on 4 July 2012, CERN is due to make an important announcement regarding the discovery (or not) of the Higgs particle at the LHC. This announcement is likely to be an important milestone in physics. It comes after a long drought of significant fundamental physics discoveries, during which SSC was canceled in the US and the LHR commissioned in Europe. In this drought there has also been the 40-year rise (and perhaps fall) of much theoretical ratiocination that lacks experimental or observational confirmation. I guess this 4th of July is going to be important for the future of physics and its funding, and I’d very much like to understand the significance of the Higgs, so that I can better appreciate what is going on. I’m not nearly clever enough to do this without help. Hence the question below.
The best source of information I’ve found so far is a http://minimafisica.biodec.com/Members/k/2011/bcstolhc.pdf given by Steven Weinberg to an audience of non-particle physicists (I’m one) at the 50th anniversary of the publication of the successful Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity, in 2007. I’m afraid it’s at the limit of my comprehension and has therefore generated some odd questions. Before I put one of them I hasten to add that I don’t doubt the wisdom of anything Weinberg said.
He places emphasis on the importance of the spontaneous breaking of an exact symmetry, as recognised by the post-BCS particle-physics community and which, mandated by the Goldstone-Salam-Weinberg theorem, results in the production of an exactly massless particle. Weinberg refers to such a particle as a Goldstone excitation in his mention of cosmological fluctuations; an excitation that because it has no mass, has “zero frequency”.
If broken symmetry and zero mass are both “exact”, I take him to mean that the field corresponding to the zero-frequency particle is “exactly” constant and not time-varying.
Now switch to considering a field often taken as a manifestation of broken symmetry — the magnetic field due to a solid lump’s aligned atomic spins. Is this (everyday language) “static magnetic field” associated with a (particle physics language) “massless Goldstone excitation”? Or are these just convenient effective descriptions invoking the mysterious wave-particle duality? I have enough trouble imagining long wavelength EM waves being represented as photons, let alone a static magnetic field masquerading as a particle. Goes against my understanding of harmonic analysis.
The best source of information I’ve found so far is a http://minimafisica.biodec.com/Members/k/2011/bcstolhc.pdf given by Steven Weinberg to an audience of non-particle physicists (I’m one) at the 50th anniversary of the publication of the successful Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity, in 2007. I’m afraid it’s at the limit of my comprehension and has therefore generated some odd questions. Before I put one of them I hasten to add that I don’t doubt the wisdom of anything Weinberg said.
He places emphasis on the importance of the spontaneous breaking of an exact symmetry, as recognised by the post-BCS particle-physics community and which, mandated by the Goldstone-Salam-Weinberg theorem, results in the production of an exactly massless particle. Weinberg refers to such a particle as a Goldstone excitation in his mention of cosmological fluctuations; an excitation that because it has no mass, has “zero frequency”.
If broken symmetry and zero mass are both “exact”, I take him to mean that the field corresponding to the zero-frequency particle is “exactly” constant and not time-varying.
Now switch to considering a field often taken as a manifestation of broken symmetry — the magnetic field due to a solid lump’s aligned atomic spins. Is this (everyday language) “static magnetic field” associated with a (particle physics language) “massless Goldstone excitation”? Or are these just convenient effective descriptions invoking the mysterious wave-particle duality? I have enough trouble imagining long wavelength EM waves being represented as photons, let alone a static magnetic field masquerading as a particle. Goes against my understanding of harmonic analysis.
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