The spin-statistics tag has no wiki summary.
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NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms
From the papers by Barahona and Istrail I understand that a combinatorial approach is followed to prove the NP-completeness of non-planar Ising models. Basic idea is non-planarity here. On the other ...
2
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1answer
56 views
Is conservation of statistics logically independent of spin?
If the number of fermions is $n$, we expect the quantity $(-1)^n$ to be conserved, i.e., $n$ never changes between even and odd. This is known as conservation of statistics. In the normal context of ...
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Ising Hamiltonian for relativistic particles
An Ising system is described by the simple Hamiltonian:
$$H = \sum\limits_{i} c_{1i} x_{i} + \sum\limits_{i,j} c_{2ij} x_i x_j \,\,\,\,\,\,\,\,\,\,(1)$$
Here the $x_i$ are spins (+1 or -1 in units ...
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1answer
116 views
Does the Higgs mechanism address the spin statistics problem?
Since the Higgs mechanism is so intimately tied to binding together massless chiral fermions, does it happen to have anything to say about the spin statistics issue?
I'm actually assuming the answer ...
3
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0answers
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Question about the derivation of an equation in full replica symmetry breaking solution
Using replica method and saddle point method, the free energy of a magnetic system can be expressed as
$$-\beta[f]=\lim_{n\to0}\{\frac{-\beta^2J^2}{4n}\sum_{a\ne b}q_{\alpha\beta}^2-\frac{\beta ...
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1answer
247 views
Why is the majorana particle a fermion?
My knowledge of quantum mechanics is rather limited, but what I always understood was that Bosons have integer spins and Fermions have half-integer spins.
My question is very simple: the Majorana ...
1
vote
1answer
588 views
Partition function of bosons vs fermions
I have two atoms, both of which are either bosons or fermions, with four allowed energy states: $E_1 = 0$, $E_2 = E$, $E_3 = 2E$, with degeneracies 1, 1, 2 respectively.
What's the difference between ...
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2answers
195 views
Fermion Field of Standard Model
Why fermion field is treated as anti-commuting and boson field as truly classical in standard model?
2
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2answers
161 views
Why is fractional statistics and non-Abelian common for fractional charges?
Why non integer spins obey Fermi statistics?
Why is fractional statistics and non-Abelian common for fractional charges?
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3answers
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What are distinguishable and indistinguishable particles in statistical mechanics?
What are distinguishable and indistinguishable particles in statistical mechanics? While learning different distributions in statistical mechanics I came across this doubt; Maxwell-Boltzmann ...
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2answers
166 views
Why Pauli exclusion instead of electrons canceling out?
To quote Wikipedia,
The Pauli exclusion principle is the quantum mechanical principle that no two identical fermions (particles with half-integer spin) may occupy the same quantum state ...
5
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1answer
175 views
Does there exist a nonrelativistic physical system in which the effective long-distance fields violate spin/statistics?
The nonrelativistic Schrodinger field allows spin independent of statistics, so that you can imagine a nonrelativistic Schrodinger scalar field with Fermionic statistics, or a Schrodinger spinor field ...
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2answers
264 views
Occam's razor on spin statistics theorem?
Highly related to A reading list to build up to the spin statistics theorem
I see 2 parts to the spin statistics theorem:
(spin $n$ or $n+\frac{1}{2}$)
step 1 given that a spin is integral or ...
10
votes
1answer
237 views
Time reversal symmetry and T^2 = -1
I'm a mathematician interested in abstract QFT. I'm trying to undersand why, under certain (all?) circumstances, we must have $T^2 = -1$ rather than $T^2 = +1$, where $T$ is the time reversal ...
6
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1answer
360 views
Time reversal symmetry and T^2 = -1
I'm a mathematician interested in abstract QFT. I'm trying to undersand why, under certain (all?) circumstances, we must have $T^2 = -1$ rather than $T^2 = +1$, where $T$ is the time reversal ...
11
votes
1answer
186 views
Can the CPT theorem be valid if Lorentz invariance is only spontaneously broken?
Earlier, I asked here whether one can have spontaneous breaking of the Lorentz symmetry and was shown a Lorentz invariant term that can drive the vacuum to not be Lorentz invariant. How relaxed are ...
12
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1answer
385 views
A reading list to build up to the spin statistics theorem
Wikipedia's article on the spin-statistics theorem sums it up thusly:
In quantum mechanics, the spin-statistics theorem relates the spin of a particle to the particle statistics it obeys. The spin ...
2
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2answers
271 views
Example of a wavefunction that cannot be represented by a single Slater determinant
I know that in general, interacting fermions cannot necessarily be described by a single Slater determinant. Can anyone provide a simple example of a state that has no such representation?
6
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2answers
970 views
What causes the Pauli exclusion principle (and why does spin 1/2 = fermion)?
It seems to be related to exchange interaction, but I can't penetrate the Wikipedia article. What has the Pauli exclusion principle to do with indistinguishability?
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2answers
170 views
existing bounds on maximum density achieved by a Bose condensate
As we know, fermions are subject to exchange interactions that limit the densities they can achieve. However bosons (simple or composite) are not constrained by this, which implies physical phenomena ...
