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To: Alamo-Girl
Nothing about particle indistinguishability says that indistinguishable particles are not discrete objects. A hydrogen molecule is composed of two indistinguishable electrons, and two indistinguishable protons; not 1.9 electrons, and not 2.1 protons. In more complex molecules, particle indstinguishability simply isn't observed. In a molecule of glucose, every single proton is a distinguishable particle; it has a nuclear spin wavefunction that can be separately and discretely observed.
689 posted on 11/25/2003 12:58:26 PM PST by Right Wing Professor (...who has had enough of obscurantist misrepresentations of physics.)
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To: Right Wing Professor
A hydrogen molecule is composed of two indistinguishable electrons, and two indistinguishable protons ...

[Cough. Ahem. Nervous shifting in my seat.]

691 posted on 11/25/2003 2:31:19 PM PST by PatrickHenry (Hic amor, haec patria est.)
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To: Right Wing Professor
Thank you for your reply!

Nothing about particle indistinguishability says that indistinguishable particles are not discrete objects. A hydrogen molecule is composed of two indistinguishable electrons, and two indistinguishable protons; not 1.9 electrons, and not 2.1 protons. In more complex molecules, particle indstinguishability simply isn't observed. In a molecule of glucose, every single proton is a distinguishable particle; it has a nuclear spin wavefunction that can be separately and discretely observed.

I think you and I are doing apples v oranges here.

It started with betty boop’s remark at post 567 that ”quantum theory, on the other hand, predicts that there is no such thing as a discrete object” to which you replied at post 621 that ” quantum mechanics in fully compatible with the existence of discrete objects. “.

My response to you at post 684 was intended to stay in the realm of quantum mechanics/quantum field theory, not classical physics. I said:

As a separate entity, a discrete object cannot be comprised of elements which are otherwise connected. Quantum field theory (as compared to quantum mechanics) pertains to the field itself, the entity which exists at every point in space, which regulates the creation and annihilation of the particles. Among other things, it corrects the problem with identical particles [continues with discussion of bosons and fermions]:

Perhaps I should have used the Higgs field/boson as a better example of discrete objects (in the classical view) being comprised of elements which are connected (in the quantum mechanical view)?

Discussion of Standard Model of the Atom 10/98

Physicists tend to explain the Higgs as either (a) a "field" or "mechanism" or (b) a particle. Remember that in quantum eletrodynamics, the same entity can be a wave (or as a series of waves, a "field") or a particle. The Higgs, too, might have options.

Visualizing the Higgs as a particle has problems. How would a Higgs add mass to another particle? Is mass an added property, like a wad of bubble gum stuck to the side of a tennis ball? That hardly seems likely, but it is hard to imagine a Higgs particle adding mass to other particles without imagining some sort of aggregation. Furthermore, if the Higgs is the contributor of mass, it presumably must have enormous mass itself. If it has such mass, why hasn't it been observed already? Even nimbler, lighter, and shorter-lived particles might be elusive but they have been observed. Why not the densest thing in the universe?

As a field, perhaps the Higgs makes more sense. The Higgs needs to provide a theoretical mass value when it is factored into other equations/reactions. Whereas a Higgs particle doesn't contribute anything to calculations requiring mass, a Higgs field does. Imagine that a particle gained its mass, not by aggregation with another particle, but by interacting with a force field. David Miller, of University College, London, explains the field/interaction idea this way: "In order to give particles mass, a background field is invented which becomes locally distorted whenever a particle moves through it. The distortion-the clustering of the field around the particle-generates the particle's mass." The idea comes from the physics of solids. Imagine a solid, say, our tennis ball, contains a lattice of positively charged crystal atoms. When an electron moves through the lattice, its atoms are attracted to it, causing the electron's effective mass to be as much as 40 times bigger than the mass of the electron when it is free of the field. Crystal lattices carry waves without needing electrons to move through them, and these waves even behave as though they are particles. "The postulated Higgs field in the vacuum," Miller conjectures, "is a sort of hypothetical lattice which fills our Universe."

Simon Hands at CERN provides an alternative analogy. The Higgs field is like the grain in a plank of wood. "The direction of the grain is undetectable, and only becomes important once the Higgs' interactions with other particles are taken into account. For instance, all particles called vector bosons can travel with the grain...." In this case, the same particle travelling one direction (say, "with the grain") would have one identity-a photon, perhaps-and travelling in the other direction ("against the grain") another identity-perhaps a Z or W boson. The Higgs field, then, could actually simplify the Standard Model by making mass an outcome of the activity of particles rather than one of their unchanging characteristics.

Physicists' energetic defense of their informed beliefs might remind us of the story of the blind men and the elephant. For lack of proper instruments (eyes), the blind men guessed about the elephant's appearance based on the information available to them. So it is with physicists and the Higgs factor. "Take a poll in, say, the Fermilab cafeteria on what exactly the Higgs is," writes David Kestenbaum, "and you could very well start a food fight." Is it a field? Is it a split-second pairing of particles? Is it a major flaw in the Standard Model, requiring many more particles to be named? The instrumentation is vital for discovering the links and finding experimental evidence of the mass-factor, whatever it is. A new generation of colliders may well provide the answers in the next few years. CERN's LEP collider, limited by the energies it deals in, could identify a "light" Higgs factor. The facilities at Fermilab could detect a somewhat "heavier" Higgs, and CERN's Large Hadron Collider, which will replace Fermilab's Tevatron as the highest-energy accelerator in the world, would probably be able to identify an even "heavier" Higgs.

Happy Thanksgiving!

723 posted on 11/26/2003 12:44:12 PM PST by Alamo-Girl
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