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Feb2313 08:38 AM
ZapperZ

1 
36,459 
hi,
the standard (?) explanation for particle exchange to produce
repulsion and attraction is at:...

Jul2208 11:36 AM
yoyoq

1 
1,944 
I'm a little unsure about a certain part of this shown in a book.
There is an electron and a positron moving in the...

Jul2208 10:59 AM
nrqed

3 
1,707 
During a lecture about QFT...

Jul2208 02:56 AM
Zacku

1 
1,696 
I have a noobish question on spin addition. If I have a system of two particles, each with spin 1, and the spins don't...

Jul2208 02:30 AM
Usaf Moji

2 
3,120 
I'm reading Singularity Sky and came across something that didn't sound right. Charles Stross is supposed to be known...

Jul2108 09:13 PM
CJames

0 
904 
I came across my readings the idea of quantum teleportation. How there is a probability (no matter how infitessimally...

Jul2108 02:51 PM
Heisenberg.

0 
1,208 
hello,
everyone, I am not in this filed. So I get a simple question. Besides field emission and thermionic emission,...

Jul2108 04:41 AM
ZapperZ

1 
1,572 
help,see the attached file

Jul2108 03:59 AM
malawi_glenn

1 
1,127 
In QM we have the postulate of measure giving rise to the notion of wave function collapse throught measurement.
Is...

Jul2108 03:18 AM
Demystifier

3 
1,464 
I read about "pair production" how a photon can create and electron and a positron. I read the calculations and I...

Jul2008 01:36 PM
jk4

4 
1,846 
Hi all
While watching the first stage of the Tour de France, I thought of Heisenberg and his Uncertainty Principle....

Jul2008 10:46 AM
ZapperZ

38 
5,117 
One way in which Heisenberg originally argued for the uncertainty principle is by using an imaginary microscope as a...

Jul1908 10:19 PM
muppet

11 
3,275 
Hi folks!
Another stupid question: Consider a Yukawa coupling \lambda \bar{\psi}_1 \psi_2 \phi where \phi is a...

Jul1908 06:46 AM
jdstokes

7 
1,907 
Is probability a quantum observable ?
I'd like to obtain an observable operator (selfadjoint, hermitian) with...

Jul1908 05:55 AM
dreynaud

12 
1,654 
Hello guys, i'm just new here.I have a question about observers.
This may be a stupid question , but here it goes.
...

Jul1808 11:25 PM
kahoomann

1 
1,137 
"Anyone who has not been shocked by Quantum physics has not understood it," said N. Bohr.
Now I am confused by the...

Jul1808 03:38 PM
reilly

15 
2,689 
Can anyone help out?
I was reading about MZ interferometers on Wikipedia
...

Jul1808 03:28 PM
Ciokko

1 
2,084 
I'm reading Griffiths', and I had a question about the harmonic oscillator.
Griffiths solves the Schrodinger...

Jul1808 11:54 AM
adartsesirhc

2 
1,438 
After several failures in the past (why does the universe have to be so complicated?!), I'm once again trying to learn...

Jul1808 11:50 AM
adartsesirhc

35 
3,348 
If I'm given a photon polarized at some unknown angle, can I rotate it by 90 degrees (or by an arbitrary angle)?

Jul1808 08:00 AM
Andy Resnick

2 
1,183 
I have a question in my book where five electrons are placed in a infinite square well and Im supposed to calculate...

Jul1808 06:36 AM
drullanorull

2 
1,548 
At a given moment, the wave function of a particle in a nonnormalized state \Psi (x) = 1 + sinČ(kx). By measuring its...

Jul1708 04:16 PM
muppet

1 
1,468 
Problem:
How do you quantize a two dimensional system defined by the Lagrange's function
L=\dot{x}y  x\dot{y}...

Jul1708 07:42 AM
jostpuur

88 
13,190 
Has anybody ever tried adding mirrors around a laser tube cavity where a lot of spontaneous emission can be reflected...

Jul1608 11:31 PM
mharney1268

4 
3,627 
Given two arbitrary qubits, is there a test I can do that will always tell orthogonal qubits apart (but may fail if...

Jul1608 10:55 PM
Dragonfall

3 
1,121 
Hello everyone,
I'm trying to understand quantized vortices in rotating Bose gases. From what I understand, any...

Jul1608 09:48 PM
Creator

9 
1,903 
are there any people working on periodicly driving system?
about the floquet theory, i have a doubt.
That is, it...

Jul1608 08:48 PM
wdlang

0 
1,387 
Hi!
I want to renormalize the following UVdivergent integral using Dimensional Regularization:
\int_{...

Jul1608 02:07 PM
Sunset

2 
3,556 
hi, i have an essay question which entitles " what if planck;s constant was 6.63x10^30, how would this change the...

Jul1608 09:47 AM
exponent137

15 
3,268 
Imagine a system consisting of two hydrogen atoms with the electrons sitting in the ground state with the same spin....

Jul1608 05:43 AM
malawi_glenn

13 
1,442 
I'm a beginning QFT student, trying to slog my way through Slansky's paper...
I have some basic questions, the...

Jul1408 10:52 PM
humanino

5 
3,182 
I am wondering if anyone knows why "h" was chosen for Planck's Constant? Or did they just randomly select a letter...

Jul1408 08:02 PM
peter0302

3 
1,392 
How might one stop two dissimilar but metallic surfaces from sliding against each other? Obvious answers like weld...

Jul1408 04:10 PM
rjullom

0 
1,208 
Does a photon have a \Psi function? i.e. Is it correct to describe a photon as a wave with a real component and an...

Jul1408 03:39 PM
Usaf Moji

0 
962 
In Feynman's lectures he describes partial reflection as occuring because the "little arrows" cancel out when the...

Jul1408 02:17 PM
limey

5 
2,866 
Hello dear theorists!
Please help me to understand the following question:
I have slowly changing electric field...

Jul1408 12:52 PM
timgor

0 
1,041 
Sometimes the result looks rigorously correct while in fact it is dead wrong

Jul1408 06:58 AM
Haelfix

2 
1,826 
I started working on this topic and thought I would post it for other to contribute their ideas. The ClebschGordan...

Jul1308 04:49 PM
Marty

16 
3,134 
This seems a simple problem, but managed to confuse me and my friends a bit, it's definitely not a standard problem...

Jul1308 10:16 AM
Fredrik

1 
1,129 
Dear all,
While I was reading chap2 of Peskin, I got some questions.
(1) The vanishment of the commutator of...

Jul1308 01:04 AM
hellfire

3 
2,036 