Path: cactus.org!milano!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!qt.cs. + utexas.edu!yale.edu!cmcl2!adm!smoke!gwyn From: firstname.lastname@example.org (Doug Gwyn) Newsgroups: sci.crypt Subject: Re: Are there truly random phenomena? Message-ID: <email@example.com> Date: 14 Aug 91 04:13:54 GMT References: <1991Aug9.firstname.lastname@example.org> <618@tymix.Tymnet.COM> + <email@example.com> Organization: U.S. Army Ballistic Research Laboratory, APG, MD. Lines: 42 In article <firstname.lastname@example.org> email@example.com (Lee Campbell) writes: > Quantum Mechanics (and its children quantum electrodynamics, quantum >chromodynamics, etc) are based on the assumption that all phenomena have >some randomness. There are theories called hidden variable theories that >postulate that the "randomness" we see is only the predictable behavior >of deeper level structures of which we are ignorant. Unfortunately, the >quantum theories, which assume true randomness, have been spectacularly >successful in predicting results, in some cases to 12 or more decimal >places (certain electron energy levels). Meanwhile, nobody has come up >with a working hidden variable theory despite the fact that such notables >as Dirac and Einstein devoted decades to the problem. Closer than most, but still not quite 100%. The quantum "randomness" is not merely ASSUMED, it has been DEMONSTRATED and thus is a required feature of any such theory. Einstein did not actually spend much time working on a so-called "hidden variable" theory; his concern was with pure field theories, superficially (at least) completely deterministic. The connection with quantum theory was deferred to the distant future. (Some clues to how this connection MIGHT arise are contained in the last section of my Master's thesis. I don't claim to have PROVED anything about that, other than to show that the notion should not be rejected outright.) Schrodinger spent considerable time working along the same general lines as Einstein. I'm less familiar with the speculative theoretical work of Dirac and Heisenberg, which were more closely tied to the "orthodox" views of QM. However, it is interesting that such luminaries in physics did not consider the issue nearly as settled as textbooks normally make it out to be. In fact, the orthodox view appears to be "don't worry if you don't understand it, just be happy that the rules allow you to compute a few things correctly". (I utterly disagree with the philosophy behind that point of view.) I think that recent results have pretty well ruled out "hidden variable" quantum theories in the traditional meaning of the phrase. That doesn't mean that anybody yet has a really fundamental understanding of where the apparent quantum randomness comes from, but we do have to acknowledge that it really is there, and it really is different from what would ensue merely from incomplete information of an inherently deterministic system. Anyway, back to the theme of this newsgroup, according to the best of our knowledge, you really can rely on quantum randomness to be truly random.