Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Kryptid on 18/07/2005 06:01:42
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Several questions:
[1] Are supersymmetric particles (a.k.a. sparticles) predicted to have antiparticle counterparts? Would they be called antisparticles? Could we expect sparticles and antisparticles to annihilate upon interacting with each other?
[2] Have supersymmetric atoms (maybe called "satoms") predicted? I've heard that some sparticles are predicted to be stable, which might mean they could form stable snuclei, satoms or even smolecules. These satoms wouldn't necessarily be composed of selectrons, sneutrons, and sprotons, would they? How about gluinos, photinos, winos, or zinos?
[3] I've heard that the Planck Length (1.6 x 10^-35 m) is supposedly the smallest length that makes physical sense. Would this mean that nothing can be smaller than the Planck Length? Relativity seems to contradict that notion. In length contraction, you can theoretically contract an object to a length that is smaller than the Planck Length if you move it fast enough. Would this then refute the Planck Length as being the smallest unit of length, or could it indicate a flaw in Einstein's equations? Perhaps instead of getting asympotically closer to zero size, a moving object will get asympotically closer to the Planck Length, finally equalling the Planck Length when it travels at light speed?
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1. I believe that is true. Super-symmetric particles would have anti-super-symmetric particles, and they would annhilihate.
2. I haven't heard of any stable supersymetric partners of electrons or protons, and you would need one of each to form shydrogen. I can't tell you if the lifetime of the sproton and selectron is long enough to form shydrogen before they decay. I doubt it, since even matter formed of charmed, strange, or top and bottom quarks is too unstable to form atoms.
3. Relativity is a classical theory, so it does not recognize quantum mechanics. Relativistic QM is in use at lower energies in the standard model, but I cannot comment on Planck energy questions, and I doubt anybody knows. Clearly, "something interesting" happens to relativity at the Planck level.
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It is interesting that any theory reconciling GR and quantum theory, will have to involve all three constants--that is, "c" (speed of light), G (gravitation) and H bar (Planck constant). Planck length does this and would require a form of quantum gravity at this small length. Question I wonder, "is both GR and Quantum theory needed inorder to understand objects at this Planck scale in both mass and radius?".
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I am starting to believe that the reconciliation between Relativity and Quantum Mechanics is impossible. Where is the graviton? The quantum of gravity. I think that both theories form a kind of duality, just as the wave-particle concept or the chinese Ying-Yang. They are both needed in the understanding of the Universe and we should stop trying to look for a quantum of gravity that is just an illusion...
Pablo Gonzalez
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I think you're on the right track. There seems little doubt that the universe is of a quantum nature and, therefore what can we do about space-time and gravity? I've read that the study of blackholes may provide such a link between GR and this quantum phenomena because isn't here, that one finds that relativity "breaks down"? Superstring theory gives one possible explanation but some still feel it is more epistemologic than scientific.
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Re: Supercyd's question no.3
My understanding (which is probably wrong, admittedly) is that not only can you not have a length smaller than the planck length (call it PL for short), but you can't have a difference in lengths smaller than PL. So the issue isn't just what happens when the object contracts down to PL. It's that the contraction must take place in stages - or "quantum jumps". So the object doesn't shrink continuously from, say, 10 PLs to 9.99999 PLs to 9.999985 PLs ... etc. Its length jumps from 10 PL to 9 PL, and can't be any length in between.
Does that make sense, or am I completely off track?