Search Results
| Search type | Search syntax |
|---|---|
| Tags | [tag] |
| Exact | "words here" |
| Author |
user:1234 user:me (yours) |
| Score |
score:3 (3+) score:0 (none) |
| Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
| Views | views:250 |
| Code | code:"if (foo != bar)" |
| Sections |
title:apples body:"apples oranges" |
| URL | url:"*.example.com" |
| Saves | in:saves |
| Status |
closed:yes duplicate:no migrated:no wiki:no |
| Types |
is:question is:answer |
| Exclude |
-[tag] -apples |
| For more details on advanced search visit our help page | |
Results tagged with quantum-mechanics
Search options not deleted
user 206319
Quantum mechanics describes the microscopic properties of nature in a regime where classical mechanics no longer applies. It explains phenomena such as the wave-particle duality, quantization of energy, and the uncertainty principle and is generally used in single-body systems. Use the quantum-field-theory tag for the theory of many-body quantum-mechanical systems.
1
vote
1
answer
786
views
Density of states in 3D quantum mechanics
For a particle that is confined in a volume $V$ the following relation is often used:
$\Delta^3 n = \frac V {(2 \pi \hbar)^3}\Delta^3P$
Since the particle is confined in $V$ it it doesn't have a deter …
- 1,978
1
vote
1
answer
50
views
Why $ \vec \mu$ is induced by $\vec B_{ext}$?
I have read that in the presence of an external magnetic field $\vec B_{ext}$ the magnetic moment induced on a paramagnetic ion is $\vec \mu=g \mu_B \vec J$ where $g$ is the Landé g-factor.
Why is $\v …
- 1,978
3
votes
2
answers
425
views
Why can we factorize the state of a particle?
I read about factorization in these two cases:
When spin and position are not coupled it is
possible to factorize the state in a wave function and a spinor $|\psi\rangle|\chi\rangle$
If there are two …
- 1,978
0
votes
1
answer
111
views
Identical particles far apart
There are two identical particles, $a$ and $b$. The particle distance is large enough that interaction term, in the Hamiltonian, is negligible.
The Hamiltonian of the system can be written as:
$$\hat …
- 1,978
1
vote
1
answer
206
views
Why parity required symmetry?
I'm studying parity for the first time but there is something I don't understand.
I read that a system conserves parity if every experiment is the same in a mirror that is also $180^{\circ}$ flipped. …
- 1,978
0
votes
1
answer
69
views
Are this isospin eigenstate same energy states?
Let's consider a system of two nucleons (protons and neutrons). $\hat T$ is the total isospin operator and $\hat T_3$ it's projection on the axis. The eigenstate are:
singlet state: $|0,0\rangle$
trip …
- 1,978
0
votes
0
answers
28
views
Factorization of non-stationary states
It is common to read about two particles systems in which the particles are independent and their wave function is factorized as $\psi(x_a) \psi(x_b)$ where $\psi(x_a)$ and $\psi(x_b)$ are stationary …
- 1,978
0
votes
2
answers
100
views
Dimensionality of the quantum space of states
I don't understand what is the dimension of the space of the states because it looks different dependently on the base that I choose, for example:
If I use the position representation (the base are t …
- 1,978
5
votes
4
answers
1k
views
Spin of two identical particles
I read that when I have two identical particles with spin 1/2 there are 4 possibilities:
|↓↓⟩,|↑↑⟩,|↑↓⟩,|↓↑⟩.
Then since there is the symmetrization requirement I can take as eigenvalues the follow …
- 1,978
10
votes
3
answers
3k
views
Why is representation theory important in physics?
Given a certain group we can find many representations of it. And If I'm not wrong a representation is a group itself. For example, given the group of the unitary 2x2 matrices with determinant 1 $SU(2 …
- 1,978
5
votes
3
answers
655
views
Why don't electrons occupy infinite degenerate states with the same energy?
I have a question about the degeneracy of energy levels in atoms and the Pauli exclusion principle.
I understand that, according to the Pauli exclusion principle, each orbital can host a maximum of tw …
- 1,978
4
votes
1
answer
512
views
Probability that two identical particles are somewhere
Let's say we have two identical particles, $r_1$ is the position of the first particle and $r_2$ is the position of the second particle. The wave function is $\psi(r_1,r_2)$. Since these particles are …
- 1,978
0
votes
1
answer
86
views
Why Consider Only Triplet States for Spin in $2$-Electron Systems?
I have a question regarding systems of 2 electrons and their spin properties. When the Hamiltonian of a system of 2 electrons can be written as a sum of two single-particle Hamiltonians that are ident …
- 1,978
0
votes
1
answer
240
views
Quantum mechanics, angular momentum in spherical coordinates
I've seen many times the angular momentum operators $\hat L_x, \hat L_y,\hat L_z$ expressed in spherical coordinates but I've never seen the components operators $\hat L_\rho, \hat L_\theta, \hat L_\p …
- 1,978
0
votes
1
answer
276
views
Angular momentum and Schrodinger equation
I'm studying stationary states and their orbital angular momentum in 3D Schrodinger equation. I have tried to understand by myself the situation but I get lost. I think it might be useful to know whic …
- 1,978