Questions tagged [spin-statistics]

The tag has no usage guidance.

136 questions
18 views

Typo on 'PCT, Spin and Statistics, and All That'

On page 163, formula (4-76) says $$(Ψ_{10},…Ψ_0)=…$$ but it should say $$(Ψ_{10},…Ψ_{10})=…$$ right?
124 views

96 views

CPT transformation for bilinears

In the page 5 of the document 'CPT Symmetry and Its Violation' by Ralf Lehnert (https://core.ac.uk/download/pdf/80103866.pdf), appears a discussion about how the spin-statistics theorem applies to the ...
306 views

What is the spin-statistics theorem in higher dimensions?

In $d = 3+1$ dimensions, the spin-statistics theorem states that fermionic particles have half-integer spin and bosonic particles have integer spin, in a well-behaved relativistic quantum field theory....
232 views

Why are Spin 1/2 particles invariant to $4\pi$ rotation loops while Spin 1 particles are invariant to $2\pi$ loops?

Why do Spin 1/2 particles when turning them by 360 deg get a phase factor of -1 and a loop of 720 deg leads to the identity while for spin 1 particles a loop of 360 deg gives already the identity?
54 views

Is the spin-statistics theorem true for antifermions?

The spin-statistics theorem says that having a system of identical fermions, the total wavefunction is antisymmetric with respect to exchange of any two fermions. My question is, does this hold for ...
45 views

Particle statistics in fractal dimensions? [closed]

We know that fermions and bosons are the only two (indistinguishable) particle statistics for $d\geq 3$, and that anyons are for $d=2.$ What if the space were a fractal? Like the Sierpinski gasket, ...
107 views

Spin statistics from the fundamental group of $SO(D)$

I read the answer to this question and am very intrigued by its simple and elegant explanation of the emergence of anyon, boson & fermion statistics. @Trimok basically says: In a space-time ...
43 views

Identical Spin Fermions in the same orbital state: Finding total spin

Say we have two identical spin 3/2 particles in the same orbital state. What are the possible total spin? I know that there is a simple formula for adding angular momenta, but this breaks down when ...
154 views

Intuition behind Pauli’s Principle

While reading about electronic structure of multi-electron atoms, Pauli’s Principle comes out to be a very important feature. But it feels very vague as little explanation is given about it. I mean ...
108 views

Can we say that bosons attract each other?

We know that bosons donot follow Pauli exclusion principle, thus they can occupy the same state. But is it equivalent to say that bosons attract each other?
58 views

A possibility of the theoretical derivation of Pauli's Exclusion Principle [duplicate]

Pauli's exclusion principle tells us (in an informal language) that each and every electron in an atom is unique. When I searched for a derivation , I got nil everywhere (even the wiki site says only ...
36 views

Is Quantum spin greater than $1$ possible? [duplicate]

I know that fermions have a spin of half of and bosons have a spin of 1 but at many places I have seen that their is written that spin for a boson can be 0,1,2.... Is there any physical meaning of ...
44 views

Spin Statistics Theorem wikipedia

I have some questions about a terminus in wikis article about the Spin–statistics_theorem: https://en.wikipedia.org/wiki/Spin%E2%80%93statistics_theorem#General_discussion ...so in paragraph "A ...
65 views

Entropy without thermodynamic limit

I am reading K. Huang Statistical Mechanics (2Ed , Wiley, 1987) Chapter 14 Ising Model. The paragraph of title Absence of Spontaneous Magnetization in One Dimension bothers me. Problem discussed is ...
111 views

Ising 2d Using Montecarlo Metropolis (Markov chain method)

I'm doing as a personal training the 2d Square lattice Ising model. I decided to go with metropolis Monte Carlo method using Markov chain. I'm not into this methods, but I'm just using them as a tool (...
101 views

Spin statistical theorem in curved spacetime

In Wikipedia https://en.wikipedia.org/wiki/Spin%E2%80%93statistics_theorem?wprov=sfti1 It states that “The proof requires the following assumptions: The theory has a Lorentz-invariant ...
54 views

Mathematical proof that Fermions are half-integer spin particles, and half-integer spin particles are Fermions [duplicate]

See: Why must fermions be antisymmetric? What causes the Pauli exclusion principle (and why does spin 1/2 = fermion)? It was said that all fermions were half integer spin particles and all half ...
167 views

Apparent discrepancy between partition function from density matrix and partition function from counting microstates in finite level system

Consider a quantum two-level system indexed by states $|l\rangle = |0\rangle,|1\rangle$ and energies $\epsilon_l$, where $\epsilon_0 = 0$,$\epsilon_1 = \epsilon$. I throw in 2 bosons into the system ...
264 views

Boson or Fermion

How do you deduce that an atom is a fermion or a boson? Do you determine it from the number of neutrons because "electrons and protons cancel out each other in a neutral atom"? What does this have to ...
76 views

How do you know $W$ and $Z$ bosons are really bosons and not fermions?

It has been always said that $W$ an $Z$ bosons are bosons and not fermions but is there any experimental trial that prove that? Has anyone put two of them in the same quantum state or studies have ...
127 views

1D Ising Model in B-Field Partition Function (2 Spins)

I have a one-dimensional system of two Spins ( $\sigma_1$, $\sigma_2$) in a magnetic field B with energy: \begin{equation} E = -J \sigma_1 \sigma_2 -B (\sigma_1 + \sigma_2) \end{equation} each $\sigma$...
176 views

19 views

Is there a leptonic analog of stimulated emission (ie suppressed emission)?

The phenomenon of stimulated emission is often explained by the fact that bosons are excitations in fields that are created by operators that are symmetric under exchange of order. The converse of ...
2k views

Theoretical Proof of Pauli's Exclusion Principle

"No theoretical proof of the Pauli's Exclusion Principle can be given as yet and for the present it must be regarded as something empirical added to and regulating the vector atom model." I've found ...
4k views

Are protons and neutrons affected by the Pauli Exclusion Principle?

I'm very confused about the Pauli exclusion principle. Wikipedia states it as "two identical fermions cannot occupy the same quantum state in a quantum system". I understand this for electrons that ...
224 views

Quantum partition function for spins

I am trying to understand the quantum partition function for spins. The quantum partition function is $$Z=\text{tr}\left( e^{-\beta \hat{H}} \right)$$ where tr is the trace, and $\hat{H}$ is the ...
2k views

Why bosons have integer spin and fermions have half-integer ones?

Due the fact that the fermions are the "block particles" and the bosons are the "carriers" I just came out with the question that, why the "block particle" have half-integer spin and the "carriers" ...
122 views

Why a half-integer spin implies “antisymmetry” on the wave function? [duplicate]

I've read that the Pauli's exclusion principle can be explained because the wave function of fermions (half-interger spin) change sign when you permute two arguments and that this makes it impossible ...
133 views

Why does a quantum gas lose its “quantum nature” in the limit $(\epsilon-\mu)/k_BT\gg1$?

Mathematically, the Fermi-Dirac (FD) distribution and Bose-Einstein (BE) distribution coincides with the Maxwell-Boltzmann (MB) distribution in the limit $(\epsilon-\mu)/k_BT\gg 1$. Therefore, in this ...
224 views

1k views

Integral spin and half integral spin

I am reading a book (Laudau and Lifshitz, Vol. 4, page 94) and it derived why spin-0 should obey Bose quantization and spin-1/2 should obey Fermi Quantization. Then it says, all integral spin ...
164 views

What underlies super-selection rule in quantum field theory?

Super-selection rule in quantum field theory states that superpositions of two states with different charges do no exist in nature. What does "charge" mean in this context? Is there a deeper ...
54 views

Ginibre inequality in Aizenman & Simon paper

In the paper linked below equation (4) is not well justified. After a lot of reasoning I still can't figure out why the need of taking the hamiltonian in the H' form and how should I use Ginibre ...