The discussion revolves around the nature of the Pauli exclusion principle and its implications for forces, particularly in the context of pressure and spin in quantum mechanics. Participants explore whether the effects associated with the Pauli exclusion principle can be classified as a force and delve into the concept of spin and its relationship to magnetic moments.
Participants do not reach a consensus on whether the effects of the Pauli exclusion principle can be classified as a force. There are multiple competing views regarding the nature of spin and its implications for magnetic moments, as well as differing opinions on the relationship between magnetism and special relativity.
Participants express uncertainty about the definitions and implications of terms like "force" and "pressure" in the context of quantum mechanics. There are also unresolved questions regarding the classical interpretation of spin and its relationship to magnetic moments.
The standard term used is "pressure", specifically "degeneracy pressure", when dealing with the Pauli exclusion principle. You are right that pressure essentially means that work must be done to compress something, and that is also associated with forces. It's an unusual force though, because it is a kind of community property, and most forces are pairwise interactions between particles. I suppose it's all in how you treat it-- I tend to avoid taking the labels of physics too seriously. Your question is actually an excellent example of why that is good to avoid, but maybe someone else can find a way to answer it more directly by couching it in a more general mathematical framework. Chances are, however, if they do they will not be answering the question you intend!Dropout said:If it takes energy to squeeze matter, then its a force at work right?
It tracks a conserved quantity, angular momentum, and also describes the symmetry of a system under rotations. There are deep connections between those, and if you ask a mathematical physicist you will probably get a very complete and very difficult answer! You may need to specify the specific situation you are trying to understand, and the answer will be, "the concept of spin helps you organize the behaviors you will see in that situation". General enough? But the point is, one can only be general when talking about "what is"-- it's not a function that physics is perfectly constructed to perform (check out the "wave/particle duality" thread to see what I mean)!And what is spin? I can put the quantized nature of spin in the back of my mind for a moment, but what the heck does spin do?
It's randomly oriented, yes, but it's also quantized-- if you measure the spin in some direction, it has to come out certain values separated by integers.Dropout said:Also, is that magnetic moment randomly oriented with the 3 spatial dimensions, all 360 degrees?
Dropout said:Spin is a magnetic moment of an electron particle, how fast would the electron particle have to travel to create the exact magnitude of that magnetic moment, classically speaking. Speed of light?
Also, is that magnetic moment randomly oriented with the 3 spatial dimensions, all 360 degrees?
That's a good point, pressure for a bunch of particles just means there's a momentum flux through any imaginary surface, so there doesn't need to be any forces, and degeneracy pressure is just like that too. What brings a force in is the implication that if we are going to compress this gas and do work on it, we are going to need some boundary that can contain the particles, i.e., that can exert a force on them. So the "force" that the OP is asking about really doesn't come from the pressure itself, it comes from whatever we are using to force the contraction of the gas. The pressure force may then be seen as the action/reaction pair of whatever real force is being used to accomplish the compression.lbrits said:I'd just like to add that it is analogous to the "pressure" of an ideal gas of non-interacting particles.