Questions tagged [pauli-exclusion-principle]
The Pauli exclusion principle states that two identical fermions, (so with half-integer spin) cannot occupy the same quantum state simultaneously, and thus share all of their quantum numbers. Also use for structure and classification schemes involving antisymmetry.
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How many electrons can be there in a cubic box of unit volume? [closed]
Recently I saw a video saying that due to the Pauli's exclusion principle there can only be a fixed number of electrons in a place but for photons it doesn't hold true as it's spin is different. So ...
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How can two electrons form the anti-symmetrical state?
Suppose that I have two electrons in a box that were originally spread by a infinite potential wall. The two electrons are in their ground state wave function (sine function).
Now I removed the ...
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What determines the energy spacing of individual orbitals within an energy band in a material?
Within a material, electrons exist within energy bands, often referred to as the "conduction" band and the "valence" band (and I imagine there can be other named bands as well). I ...
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Is there a spin-1/2 hadron composed entirely of up quarks? [duplicate]
I am curious to know if there exists a spin-1/2 hadron that is composed of three up quarks. I understand that in quantum chromodynamics, baryons are formed of three quarks, each carrying a distinct ...
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Understanding the Nuclear Spin of Boron-10: Why is it Spin-3?
I am delving into the nuclear spin characteristics of Boron-10, which notably has a nuclear spin of 3. While I have a foundational understanding of some quantum mechanical principles, the specific ...
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Mechanistic Explanations for Electron Degeneracy Pressure [closed]
Most explanations of electron (or any fermion) degeneracy pressure cite Pauli's exclusion principle for fermions. I believe such explanations tell us why we should believe such phenomena exist, but ...
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Electrons decaying into heavier particles
Suppose we have a system of electrons a very tightly confined space (like a tiny magnetic trap).
Let's say we continually increase the degree of confinement such that the electrons are confined into ...
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Term symbols and the role of antisymmetrization
In the Hartree-Fock method for many-electron atoms, for a given eigenspace $\mathscr{E}$ of the unperturbed Hamiltonian (in a.u.)
$$\hat{H}=\sum_{i=1}^Z \Big(-\frac{1}{2}\nabla^2_i-\frac{Z}{|\vec{r}_i|...
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Is Pauli exclusion or not reason for formation of matter in the Universe?
Pauli exclusion principle says multiple fermions having identical quantum state cannot occupy same physical space.
When it says "same physical space"...
Is it referring to same location in ...
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Help needed to understand whether multiple fermions can occupy same physical space or not
As per my understanding:
Multiple fermions cannot have the same quantum state (as per Pauli exclusion principle)
Multiple fermions can occupy the same physical space as long as they have different ...
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Antisymmetrization of the electronic wave function
I'm studying systems of many electrons (for Theoretical Quantum Chemistry) from Landau, Quantum Mechanics (non-relativistic theory), chapters 61, 62, and 63.
I wanted to ask for good references to ...
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Symmetry of the hydrogen molecule wave function
Due to their overlapping wave functions, electrons in an $H_2$ molecule must posses opposite spins. The nuclei (two protons) on the other hand are far enough apart for the Pauli exclusion principle to ...
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Are the protons in dihydrogen in the same quantum state?
The electrons in the hydrogen molecule experience the same potential and are thus in the same state, so the Pauli exclusion forces them to have opposite spins.
Since the protons are identical by ...
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Degeneracy of term-symbols and Pauli exclusion principle in the Russell-Saunders scheme
In the Russell-Saunders scheme, let us consider a configuration of $N$ equivalent electrons (i.e., belonging to the same subshell $(n,\ell)$). Let $|L\ S\ M_L\ M_S\rangle$ denote a common eigenstate ...
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State function of two electrons in 1D box
I would like to know how to derive the wave function of two non-intering electrons in one-dimensional space by accounting their spin and Pauli's exclusion principle.
$\Psi(x_1, x_2,\sigma_1, \sigma_2)$...
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Can two electrons (with different quantum numbers) exist at the same place in space?
I was studying about the arrangements of orbitals in an atom and saw a simulation of the arrangement and that some area of a smaller orbital such as a 1s is contained inside a bigger orbital of 2s (a ...
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Two electrons in $1\text{s}$ orbit
Suppose that we have two electrons in $1\text{s}$ orbit. According to the Pauli principle, they should have different spins, one up and one down. If I want to calculate the total angular momentum, ...
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Does the Pauli exclusion principle apply to mesons?
According to the Pauli exclusion principle, two identical fermions cannot occupy the same quantum state simultaneously, but two bosons can. Mesons are bosons, but composed of two quarks, and quarks in ...
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Why doesn't the Pauli exclusion principle apply to bosons?
Everything I've read online seems to say/imply that the Pauli exclusions principle only applies to fermions and not bosons.
As I understand it the Pauli exclusion principle arises when the spatial ...
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Baryon wavefunctions
The textbook I am currently using states that when all quarks have the same flavor, there are no $J=1/2$ baryon wavefunctions for the ground state $l=0$.
Is this an experimental result or is there a ...
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Paired electrons and entanglement [duplicate]
Note to duplicate concerns: How is that the same question as asking if different orbitals are entangled? I am talking about paired electrons in the same orbital orientation.
Paired electrons in an ...
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Net force on object held vertically due to friction and pauli's exclusion principle
Let us consider a cup that I'm holding vertically in my hand
I physically don't go through the cup because of the pauli's exclusion principle where electron with opposite wave function(spin)s dont ...
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Shouldn't there be 3 antibonding orbitals for diatomic hydrogen?
The bonding state of H2 is |Ψ+>|0,0>. This makes sense because there is only 1 spatially symmetric state, in which the electrons experience an attractive exchange force. (|Ψ+> denotes spatial ...
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Help with Shell Model and Pauli Exclusion Principle
As I understand, the occupancy number in the nuclear shell model dictates the number of each type of nucleon that can occupy a specific sub-shell (angular momentum state l).
Note: s, p, d, f ...
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Is the magnetic field related directly to the Pauli exclusion principle? [closed]
The fact that the spin is a quantity related to the magnetic field, is it a consequence of the Pauli exclusion principle or vice versa?
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Can you help me derive an equation regarding Pauli's exclusion principle?
I am writing a book entitled "Atoms" in which I must plow through much of the "old quantum theory" literature. I am reading a paper by Pauli (the first of his two seminal papers ...
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How are the orbitals named?
l = 0 to (n-1).
l is azimuthal quantum number.
n is principal quantum number.
for,
l = 0 , it is s.
l = 1 , it is p.
…
l = 99, it is what?
What is the name given to it?
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Pauli Exclusion Principle with two electrons in box
Suppose that I measure the spin of two electrons in the z direction, and that they have the same spin. Then we put both electrons in a box. After a long time, we know nothing about the spatial ...
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Are two molecules of matter in BEC phase able to occupy the same space at the same time? [duplicate]
An important property of matter taught in grade school is that it occupies space (has a volume, whether it's relatively fixed like a solid or liquid, or depends on pressure like a gas), and that ...
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When I push a 24-karat gold bar with my finger, what subatomic physics are at play? [duplicate]
I chose a pure gold bar to eliminate the possibility of any chemical reactions occurring, the same question would apply to any everyday object like a wooden block or a marble. Or it could apply with ...
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Could a $uuuu\bar{u}$ pentaquark exist?
Could a $uuuu\bar{u}$ pentaquark exist or is it forbidden due to Pauli exclusion principle?
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Spin, Pauli, and Heisenberg
Please forgive my possible misunderstandings, but I'm a YouTube physics student, and long since forgot the physics I learned in 1982...
I make a few assumptions here...
The Pauli Exclusion principle ...
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What are parahelium and orthohelium?
I have been learning a little about two-electron atoms, and there are some things that I do not fully comprehend. Some context:
In the two books I have been reading (Physics of atoms and molecules, by ...
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Physical interpretation of the Pauli Exclusion Principle
As I understand it, the Pauli Exclusion principle states that two electrons in orbitals of a given atom with the same values for quantum numbers $n$, $l$ and $m_j$ must have different (opposite) ...
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Does "non-interacting" (fermions) really mean "no interactions other than Pauli exclusion"?
When one speaks of non-interacting elections (or other ferimons), doesn't one technically mean non-interacting but with the exception of Pauli exclusion? I wonder if it is appropriate to view Pauli ...
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Must fermions be particle sized? Does pauli exclusion principle apply to large bodies?
I am wondering if all fermions must be quantum in nature or if I can build a 'classically sized' fermion.
For example, if I ensure that the total spin of all protons, neutrons and electrons in a bulk ...
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Isn't this Wired chemist totally wrong about why we can touch things? [duplicate]
The video: https://youtu.be/2xVBAqybA_8?t=185
She got the question: "if atoms are primarily composed of empty space, why can't you pass your hand through a solid object?"
Her answer is: ...
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Are there wave functions that are neither symmetric nor antisymmetric?
While proving the Pauli Exclusion Principle, one has to show that the wave function is antisymmetric for fermionic particles:
$$\Psi(x_1,x_2) = -\Psi(x_2,x_1)$$
Which is typically derived from ...
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What is the problem with classical fermionic field?
Consider classical fermionic field. We have it's action, equations of motion and so we can get it's solutions, right?
For example, we can consider gravitational solutions with fermions (in particular, ...
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Is Pauli's Exclusion Principle a restatement of what experiments have shown?
So were studying the configuration of electrons in an atom and one thing that popped up was Pauli's Exclusion Principle. In our class, as well as our textbook, it was stated as the fact that two ...
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Translation of Jordan and Wigner's original paper?
Has the original paper on the Jordan and Wigner transformation ever been translated to English?
Jordan, P., Wigner, E. Über das Paulische Äquivalenzverbot. Z. Physik 47, 631–651 (1928). https://doi....
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How does the Pauli Exclusion Principle work in Twistor theory?
Twistor theory is described sometimes as a 'natural' way to represent spinor fields.
In QED, we have the Grassmann valued spinor field $\Psi^\alpha(x)$, which naturally leads to the exclusion ...
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F-d statistics for spin 3/2 particles?
My question is according to Pauli exclusion principal no same energy state gonna occupied by similar spin particles and spin must be add up to zero . For electron it's 1/2 and -1/2 . What about spin 3/...
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How Do We Know Electron Wavefunction Should Be Antisymmetric to Electron Exchange?
As far as I know, electrons are indistinguishable particles which means that physical observables should be independent to electron exchange. Only way this can be done if the wavefunction stays the ...
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Can the "symmetric & antisymmetric" stuff of fermions & bosons be explained by first principles? [duplicate]
Many particle wave-functions to me have a very confusing methodology. I've been taught some procedure for creating wave functions that are symmetric or anti-symmetric upon exchange of coordinates.
I ...
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In Helium, why does more tightly bound mean the electrons are further apart?
In helium, the triplets ($S=1$) are lower in energy (more negative) than the singlets $S=0$.
One reason given by my lecturer is that in a triplet the spins of the two electrons are the same, then by ...
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Pauli's principle on two-electron system
I just have been introduced to the axiom "defining" bosons and fermions, namely (for fermions): Consider a collection of $N$ identical particles moving in $\mathbb{R}^3$ and having a (half-...
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Taking into account the Pauli Exclusion Principle, how many particles can you cram into a really small space?
I'm trying to understand the basic concept of the Pauli Exclusion Principle, but my former question here did not provide an answer. So let me rephrase it.
One way of describing the PEP is that you ...
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If a spin singlet cannot change, how can it interact with electromagnetism?
Let's say there's a Hydrogen atom in a spin triplet state.
$$ | \downarrow\downarrow \rangle$$
Now let's say a photon with spin 1 came along abs was absorbed by the atom. We don't know if the proton ...
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How many states are possible for two (indistinguishable) electrons with $n=2$ in an atom if we forget Pauli’s exclusion principle?
I have been told I can use $^8C_2 = 28$ to obtain the answer to this question, but I am doubtful of this result since I obtain $21$ by simply writing out the possible states as ($ml_{1}$, $ms_{1}$, $...
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