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Feb2313 08:38 AM
ZapperZ

1 
36,468 
Exactly what the title says.
I know that there exists a selection rule that ΔS=0, but I cannot find a quantum...

Aug812 10:01 AM
DrDu

2 
690 
Hey guys!
I am trying to show how singlet and triplet states mix via spinorbit coupling, but I am having some...

Aug812 07:54 AM
pfollansbee

5 
1,078 
One of the postulates of QM is that if the system is isolated from external interaction
that its wave function will...

Aug812 03:27 AM
bhobba

3 
514 
I read a short highlevel article about the pilot wave interpretation of quantum mechanics and I have some questions. ...

Aug812 02:24 AM
Demystifier

159 
19,600 
Hi everyone, I'm trying to get my head around scattering still. The books I've been looking at derive it, but then...

Aug812 12:44 AM
ardie

5 
1,148 
I'm taking an introductoruy course on QM and qubits and my professor is frustrating me by using anthropromorphic terms...

Aug712 10:01 PM
bhobba

3 
668 
I'm trying to get my head around exactly what this ultraviolet catastrophe is. So the early 20th century scientists...

Aug712 10:54 AM
USeptim

10 
2,667 
Could someone explain what a gauge theory is, both in general and how it applies to physics? Please try to keep...

Aug612 06:26 PM
dydxforsn

7 
1,158 
is it pauli or schrodinger?
is there any original reference?

Aug612 04:02 PM
dextercioby

5 
780 
Hi
I have a question regarding the MaxwellBloch equations, which I read about in a dissertation. I've looked...

Aug612 09:41 AM
Niles

10 
1,108 
Couldn't decide where to post... Chemistry or quantum mechanics... But posted here cause I wanted to know a...

Aug512 11:05 PM
Ezio3.1415

11 
1,489 
I just read this as I was skimming over the preface of a relativistic QM book. My question is this; is it the case...

Aug512 09:21 PM
atyy

8 
1,192 
There exists Green's Functions such that the solutions appear to be retrocausal. The KleinGordon equation allows for...

Aug512 08:42 PM
Bill_K

1 
550 
I am doing a measurement in a system S with the apparatus A, in an entorn E. If the system is at t0 in Sithe...

Aug512 08:16 AM
StarsRuler

2 
560 
Hi,
I am trying to find a resource that can explain how σ and ∏ lines obtain their polarizations.
I have not found...

Aug412 06:34 AM
Ashuron

4 
1,163 
When two wave functions are in perfect phase = constructive interference
when the phase difference is half (the...

Aug312 08:01 PM
San K

4 
1,996 
Hi, I'm reading about the partial wave expansion in Shankar. In his method, we expand the incident plane wave (he...

Aug312 03:18 PM
mfb

5 
916 
Hello,
Can anyone tell me how to go about studying Topological QFT. I am fine with QFT, Fibre bundles and currently...

Aug312 03:15 PM
torquil

1 
598 
General Relatitivity predicts Timelike curves and there are nonlinear extensions of mechanics which resolve the...

Aug312 01:30 PM
audioloop

4 
1,226 
Hi I was reading Feynman's third book and I don't understand why, with bosons at low temperatures, 'there's more...

Aug312 11:27 AM
zalook

1 
493 
Hello! I´m trying to read Georgi's book on Lie algebras in particle physics but am confused about the start of chapter...

Aug212 04:49 PM
king vitamin

3 
1,018 
Hi all, I'm doing a practice question in which we have a hydrogen atom in the state:
\psi = (2\psi_{100} +...

Aug212 01:49 PM
Ilmrak

12 
1,432 
Hi,
Look at
\begin{align}
& \int d^4 x d^4 x_1 d^4 x_2 d^4 x_3 d^4 x_4 \exp \\
& \times...

Aug212 12:05 PM
arojo

3 
594 
Hi all,
On p.327 in my second edition of Peskin and Schroeder, I have an expression for the one loop correction to...

Aug212 09:47 AM
muppet

0 
691 
Came across this nice list I had never seen before:
List of mathematical topics in quantum theory
...

Aug212 07:36 AM
Naty1

0 
559 
I am unsure how to (mathematically) do the partial trace of a density matrix so that I can find the expectation value...

Aug212 07:30 AM
climbon

0 
1,059 
Feynman's Lectures on Physics has an interesting graphic in volume 3, page 7_3, "Fig. 71. Relativistic transformation...

Aug112 10:16 PM
Simon Bridge

4 
1,046 
Photon Entanglement Question
Polarize a string of photons vertically. Make the polarized photons into two streams of...

Aug112 02:10 PM
DrChinese

1 
698 
Hi there,
I learn from the text that the exponential of an operator could be expanded with a series such that
...

Aug112 01:05 AM
tom.stoer

3 
874 
How can you tell if the KleinGordan Hamiltonian, H=\int d^3 x \frac{1}{2}(\partial_t \phi \partial_t...

Aug112 12:45 AM
tom.stoer

1 
580 
Can we measure the spin of a particle by measuring the force on a Magnet?
I wish to consider a modified stern...

Jul3112 11:29 PM
Prathyush

15 
1,524 
On page 237, Weinberg checked eq. (5.7.23) with an example when \mathbf p is along the three direction. Below that...

Jul3112 10:31 PM
diraq

0 
497 
I take it that it would be ok that in the classic demonstration of Lenz's law with the falling magnet, to replace the...

Jul3112 09:16 PM
gildomar

4 
895 
Does anyone know how to write the classical solution to the KleinGordon equation in NON natural units? Where do all...

Jul3112 07:01 PM
Bill_K

7 
841 
So, you got n,l,m_l,m_s. If you have two hydrogen atoms on opposite ends of the universe, it seems to me that the...

Jul3112 04:16 PM
VortexLattice

9 
1,062 
So as I was taught in Modern Physics virtual particles are allowed to exist in virtue of "borrowing" energy from the...

Jul3112 08:27 AM
tom.stoer

28 
2,861 
From the thread on Nick Herbert's proof:
harrylin:
The more I become aware about the tricky details and the...

Jul3112 03:45 AM
harrylin

60 
6,028 
Do share your thoughts on this statement.

Jul3012 06:50 PM
bhobba

14 
1,810 
Hi,
My understanding that one of the postulates of quantum mechanics is that the vector describing the quantum...

Jul3012 02:04 PM
fzero

1 
639 
I was learning about indirect band gap and it says that when the electron comes down from upper energy level to lower...

Jul3012 10:20 AM
Naty1

1 
843 