Questions tagged [spin-statistics]
The spin-statistics tag has no usage guidance.
217
questions
3
votes
1
answer
73
views
Ising Model magnetisation
I am simulating the 2D Ising Model and specifically looking at the time evolution of magnetisation $m$. Now, in the non-equilibrium state, magnetisation will grow as a power law with time $t$, if ...
5
votes
1
answer
88
views
Is there any notion of spin-statistics in curved spacetime?
It is a well established fact that all known particles obey either Fermi-Dirac statistics (for fermions) or Bose-Einstein statistics (for bosons), at least in the context of relativistic quantum ...
- 126
0
votes
0
answers
51
views
Differences in $L$ and $S$, symmetries
I have a symmetric wavefunction when $L=0$. There are a lot of proofs to see this, so I understand it.
I have a symmetric wavefunction when 2 particle of $S=1/2$ each, combine in a bound state with $S=...
- 77
0
votes
1
answer
125
views
Why do we only consider commutators and anticommutators in QFT?
While studying canonical quantization in QFT, I observed that we quantize fields either by a commutation or an anticommutation relation
\begin{equation}
[\phi(x), \phi(y)]_\pm := \phi(x) \phi(y) \pm \...
- 1,588
2
votes
2
answers
227
views
Topological proof of spin-statistics theorem confusion
I am currently studying the spin-statistics theorem. I have found a section on John Baez's website which presents a "proof" of the spin-statistics theorem. He states the theorem as:
This is ...
- 1,261
1
vote
0
answers
101
views
Covariant Spin Operator for Massless Fermions
I have been reading the paper The Covariant Definition Of Spin in Relativistic QFT by Hilgevoord and De Kerf, in which the authors derive the spin operator in relativistic quantum theories of free ...
- 3,992
0
votes
0
answers
24
views
About symmetric and anti-symmetric states of a nucleus
Ehrenfest and Oppenheimer published a paper Note on the Statistics of Nuclei in which they write:
The "rule" mentioned in paragraph is also stated in the paper. It is:
I am unable to follow ...
- 2,265
0
votes
0
answers
58
views
How is the dimension of the vector space we represent $SO(3)$ on determined when discussing the spin of a particle?
Consider a single particle with Hilbert space $L^2(\mathbb{R}^3) \otimes V_\ell$ where $V$ is a vector space of dimension $2\ell + 1$ equipped with a projective unitary representation of $SO(3)$. ...
- 3,350
1
vote
1
answer
66
views
Anticommutator Relation of Quantized Fermionic Field and Fermi–Dirac statistics: How are these related?
I'm reading the Wikipedia article about Fermionic field and have some troubles to understand the meaning following phrase:
We impose an anticommutator relation (as opposed to a commutation relation ...
- 1,395
1
vote
0
answers
46
views
Anyonic and plektonic dark matter?
The most studied types of dark matter particles include supersymmetric particles, spin particles that are either boson or fermions. I wonder if there are research about dark matter being not particles ...
- 6,611
0
votes
0
answers
72
views
Spin polarization, ferromagnetism, and size of energy gap
I thought large band gap (larger than relevant spin-spin interaction energy scale) necessarily means there is no spin-polarization (ie, not ferromagnetic). I thought the reason is that {only when ...
- 708
2
votes
3
answers
338
views
Angular momentum quantum number $l$ either integer or half integer
I am trying to understand why the angular momentum quantum number $l$ can either be an integer or an half-integer. At least this is stated in the book that I am learning from. It is the book by ...
- 121
3
votes
0
answers
101
views
Time Reversal symmetry, Quaternions, and spin-1/2 systems
When one has a system with no spin and time reversal symmetry, one can conclude that the Hamiltonian entries (in a particular basis, of course) must all be real. Can something be said about the ...
- 423
3
votes
2
answers
380
views
Why are some collections of fermions considered bosons?
I read that He-4 is a boson because the four fermions in it add up to an integer spin—of zero—hence a boson.
Whereas I thought that if the parts are fermions, so is the whole.
Is an electron pair a ...
- 154
2
votes
2
answers
222
views
Do solutions of the Schrödinger equation for multiple particles automatically obey spin-statistics?
Consider the Hamilitonian for a general two-electron system subject to an external potential $V_\mathrm{ext}$ and an interaction potential $V_\mathrm{ee}$. In this case
$$H\psi(x, y) = -\frac{1}{2} \...
