X-Message-Number: 21055 From: "michaelprice" <> References: <> Subject: Electrons, Leptons & String Theory Date: Tue, 4 Feb 2003 23:20:53 -0000 Thomas Donaldson writes: > Sorry, Michael, but I was citing (as I think you know) some suggested > theories which might join relativity and quantum theory. It is not > that we could detect fundamentally different particles which we > now see only as electrons, but that if electrons are composite then > their energy levels in various situations might differ from those > we'd expect if they were not composite. True, but strictly speaking this is not relevant, unless you're arguing that some electrons are composite and some are not (which you may well be, of course). More generally, though, energy levels in various situations may differ between different composite particles. Just as, say, composite atoms may exist in a vary of excited states, which enables them to be distinguished. The question is, therefore, could there exist different excited states of an electron due to its posited internal structure. I take it this is what you mean by: > They would be different in that sense. But the differences would be so great that we would *already* classify then as different particles. It seems a concrete example is more persuasive than an abstraction. So.... let's assume string theory is correct, for the purposes of this discussion. According to string theorists the different excited (vibrational) states of the string (with other properties held constant) correspond to particles with different masses. Hence they would be classified as different types of particles. > You are free to decide that the electrons are the "same", > whatever that means. But if they have different traits (say, a > property called "hyperspin") on different occasions, your thinking > should take account of that. Fine, but I argue that an electron's change in hypothetical "hyperspin" would cause us to classify the changed particle as a new species. It may or may not be directly relevant to my string theory example above that there *are* three "electrons" that differ only in mass. We call them "leptons", and they are, in mass order, the electron, the muon and the tau. (This is unlikely to be directly relevant since I think the different masses generated by different string excitation levels differ by the order of a planck mass or so, which is greater than the inter-lepton mass differences. Still, it is suggestive.) Robert Ettinger wrote, of my views: > So, electrons do not and cannot have subspecies, and the same is true > of elephants. I take this to mean that if two elephants are in the same > quantum state, they are "identical." Yes. > I see at least five things wrong with this. > > First, once more, it is just an arbitrary and unusual choice of language, > no doubt protected in the U.S. by the First Amendment but not useful > or appropriate. I repeat an earlier question: Is a gamma photon > "identical" to a radio photon? And I repeat my response. Same as for orange vs red photons. Perhaps you didn't see my cryoposts #20994 & #21020. > Second, saying that two elephants are identical is really the claim that > specifying the quantum state of a system tells you EVERYTHING there > is to know about the system, [....] Whoa! Stop right there. Saying two things are identical is NOT saying we know everything about them, just that everything we know about one we also know about the other. Completely and crucially different. As for the comparisons with Ptolemy's epicycles, see my response about the robustness of quantum theory, cryopost #21027. > Fourth--and I think this is most crucial for getting heads together--look > again at this: > >> occupancy number of electron orbitals >> is an absolute measure of the electron species number > > But the exclusion principle applies only to fermions, not to bosons. > Bosons, including photons, can have many in the same state at the > same time (lasers). No this is not crucial, although it is true. I could make all the same points, but in a different way, for bosons, as I have for fermions. Obviously occupancy of a bosonic state is not a measure of species number, which is why I used the example of electrons (which are fermions). I mentioned Bose-Einstein condensates as an alternative test for bosonic identity in cryopost #20884. Your point is logically irrelevant, though, since we can confine our discussion to just fermions (e.g. electrons) for ease of explication. (I presume you would not accept that fermions are identical, whilst bosons are not?) > Fifth, although this cuts no ice with some people, there is the > "philosophical" problem with any fundamental indeterminacy. You're right, that cuts no ice with me. Hugh Everett III resolved these problems, to my satisfaction. See http://www.hedweb.com/manworld.htm Cheers, Michael C Price ---------------------------------------- http://mcp.longevity-report.com http://www.hedweb.com/manworld.htm Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=21055