shepherd Posted April 1, 2012 Share Posted April 1, 2012 Can someone clarify the meaning of quantum state in the Pauli Exclusion Principle? Does the principle mean that no two fermions can occupy the same place at the same time? Link to comment Share on other sites More sharing options...
the asinine cretin Posted April 1, 2012 Share Posted April 1, 2012 (edited) Does the principle mean that no two fermions can occupy the same place at the same time? The basic summary I'm familiar with would say that no two fermions can share the exact same quantum state (i.e., identical quantum numbers). ETA: Non-scientist here. Edited April 1, 2012 by the asinine cretin Link to comment Share on other sites More sharing options...
swansont Posted April 1, 2012 Share Posted April 1, 2012 Since particles have a wavelength depending on their momentum, it becomes a little difficult to nail down "same place". They can't have the same quantum state, as was stated above. Link to comment Share on other sites More sharing options...
Steven Hawkins Posted April 4, 2012 Share Posted April 4, 2012 (edited) Same state means the same place at the same time: First of all, particles are made of many constituents, meaning they have many parts to them: These can be: quarks gluons electrons photons protons neutrons etc. Now, we will focus on the electron. The electron has recently been re-named as a fermion. What this means basically is that fermions (electrons) repel each other meaning that they bounce off each other. A good example of this is when you toss a rock to the ground, the rock then bounces off the ground. Now, pure physics tells you that if the rock is made of electrons, then electrons ( now called fermions) thus bounce off each other.. As this is the case, to the atomic scale, electrons have been also coined as fermions, which cannot "penetrate" each other.. The Puali Exclusion Principle is a rule based on this simple explanation, and thus also means, "other" technical ""descriptions"" These are every important when dealing with fermions and their calculations within a "system." What this system is, is the "location" of measure within other "subsystems in empty space." Think in terms of a "hyper cube." I have never used the Puali Exclusion Principle rules nor formulas, however, from what I know about them thus far, science has yet to find the 'proper" math involved which pin points the "absolute" definition of a system within subsystems. Another example is this: How can a star become a super nova and collapse on its own weight, when the Puali Exclusion Principle rules also apply? As such matter as we know it to be, has many other areas of research not yet still to be considered a "science." The big hurdle and obstacle to this issue is this: Scientist still "today" combine "Quantum Theory" with "Classical Physical "formulas." I think it is very important that you know that an electron---> now called fermion has 1/2 spin. What this means is that it has a 360*2 = 720 degrees of a revolution. As believed to be the case, it still has precession and a angular "initial sub type system start as well." Hope this helps. Can someone clarify the meaning of quantum state in the Pauli Exclusion Principle? Does the principle mean that no two fermions can occupy the same place at the same time? Edited April 4, 2012 by Steven Hawkins -4 Link to comment Share on other sites More sharing options...
MigL Posted April 4, 2012 Share Posted April 4, 2012 Fermions are a class of particles which obey Fermi-Dirac statistics. As opposed to bosons which obey Bose-Einstein statistical rules. Nothing more, nothing less. Link to comment Share on other sites More sharing options...
mooeypoo Posted April 4, 2012 Share Posted April 4, 2012 ! Moderator Note Fake Steven Hawkins, this is the last time we will warn you against posting your own misunderstanding of physics as an explanation to mainstream physics.If you continue disregarding our rules, you will not stay here. Please don't make us erase misleading posts.Everyone else, please IGNORE that post, since it's not what mainstream physics actually explains or says on the matter, to say the least (and be polite)Do not respond to this modnote. Link to comment Share on other sites More sharing options...
questionposter Posted April 4, 2012 Share Posted April 4, 2012 (edited) ! Moderator Note Fake Steven Hawkins, this is the last time we will warn you against posting your own misunderstanding of physics as an explanation to mainstream physics. If you continue disregarding our rules, you will not stay here. Please don't make us erase misleading posts. Everyone else, please IGNORE that post, since it's not what mainstream physics actually explains or says on the matter, to say the least (and be polite) Do not respond to this modnote. Actually, it's not completely wrong, I think your just misunderstanding him because he's using classical analogies, but in the quantum world you actually do consider classical electro-magnetic repulsion and the classical workings of electro-magnetic forces in general, although that isn't the exact reason why not more than two electrons can occupy the same quantum state, but it might be part of it since just says "when would cancel out and make each other not exist" doesn't actually tell is "why" that statistical probability occurs the way it does, although I suppose if we ask "why?" to that, then we are asking why math is the way it is, in which case we can't actually answer that. Although I would say that the rest of hist post doesn't seem like real science. Edited April 4, 2012 by questionposter Link to comment Share on other sites More sharing options...
mooeypoo Posted April 4, 2012 Share Posted April 4, 2012 If you use very very generalized analogies to try and make sense in the above post, I'm sure you can. The bottom line is that it's not an explanation for the mainstream question asked. Same state means the same place at the same time: WRONG. First of all, particles are made of many constituents, meaning they have many parts to them: These can be: quarks gluons electrons photons protons neutrons etc. Jesus, where to start. For one, protons and neutrons are comprised of quarks and gluons, they're not in the same level of the list. Now, we will focus on the electron. The electron has recently been re-named as a fermion. WRONG. Fermion is any particle that obey Fermi-Dirac Statistics. An electron is a fermion, but it's not the only fermion. Protons are fermions too. Which makes the entire section below simply utterly wrong: What this means basically is that fermions (electrons) repel each other meaning that they bounce off each other. A good example of this is when you toss a rock to the ground, the rock then bounces off the ground. Now, pure physics tells you that if the rock is made of electrons, then electrons ( now called fermions) thus bounce off each other.. As this is the case, to the atomic scale, electrons have been also coined as fermions, which cannot "penetrate" each other.. I don't even know how to start explaining it, honestly. It's pure garbage. The Puali Exclusion Principle is a rule based on this simple explanation, and thus also means, "other" technical ""descriptions"" These are every important when dealing with fermions and their calculations within a "system." What this system is, is the "location" of measure within other "subsystems in empty space." Think in terms of a "hyper cube." I have never used the Puali Exclusion Principle rules nor formulas, however, from what I know about them thus far, science has yet to find the 'proper" math involved which pin points the "absolute" definition of a system within subsystems. What? The pauli exclusion principle states that: The Pauli exclusion principle is thequantum mechanical principle that no twoidentical fermions (particles with half-integerspin) may occupy the same quantum statesimultaneously. A more rigorous statement is that the total wave function for two identical fermions is anti-symmetric with respect to exchange of the particles. The principle was formulated by Austrian physicist Wolfgang Pauli in 1925. And since "quantum states" are NOT what was said in this mumbo jumbo post, the explanation is moot. In fact, if you want to give an example of what the pauli exclusion principle is in "laymens terms", then here it is, as can be explained to kids. By using physics. Actual physics, not the made-up physics. Another example is this: How can a star become a super nova and collapse on its own weight, when the Puali Exclusion Principle rules also apply? Holy canoly. What does it have to do with anything? Seriously. Read about how stars become supernovae, it has nothing to do with this example. Hope this helps. Not only does it not, you should not do this again. If you don't know, don't post an answer. Posting an answer to a mainstream science question using mumbojumbo made up physics is AGAINST our rules. Read 'em again. ~mooey Link to comment Share on other sites More sharing options...
uncool Posted April 4, 2012 Share Posted April 4, 2012 Holy canoly. What does it have to do with anything? Seriously. Read about how stars become supernovae, it has nothing to do with this example. Well, the exclusion principle actually does play a role in star collapse. It first plays a role to stop the gravitational collapse of the star with electron degeneracy pressure, and later with neutron degeneracy pressure. =Uncool- Link to comment Share on other sites More sharing options...
swansont Posted April 4, 2012 Share Posted April 4, 2012 Fake Steven Hawkins User name is Steven Hawkins, but the avatar is of Stephen Hawking, the famous physicist. Using the label "fake" is superfluous. Same state means the same place at the same time: No. Two electrons in a He atom share the S orbital. For all we can tell, the electrons can be co-located. But they have different spin states, so this is allowed. The electron has recently been re-named as a fermion. MigL has properly addressed this. What this means basically is that fermions (electrons) repel each other meaning that they bounce off each other. Electrons repel each other anyway, because of their charge and the electrostatic force. That PEP doesn't normally enter into the picture. 2 Link to comment Share on other sites More sharing options...
juanrga Posted April 7, 2012 Share Posted April 7, 2012 (edited) Can someone clarify the meaning of quantum state in the Pauli Exclusion Principle? Does the principle mean that no two fermions can occupy the same place at the same time? Two fermions cannot occupy the same place at the same time because would require infinite energy. Think of the Coulomb energy for two electrons separated by a zero distance! The Pauli exclusion principle is another thing. The Pauli exclusion principle is a quantum mechanical principle that says that two fermions cannot be at the same quantum state simultaneously. For example, no two electrons in a single atom can have the same four quantum numbers; if n, l, and ml are the same, ms must be different such that the electrons have opposite spins. Edited April 7, 2012 by juanrga Link to comment Share on other sites More sharing options...
Reliance_On_Science Posted May 3, 2012 Share Posted May 3, 2012 I think of Pauli's Exclusion Principle simply as: No two electrons can share the same set of four quantum numbers. 1 Link to comment Share on other sites More sharing options...
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