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Feb2313 08:38 AM
ZapperZ

1 
36,164 
Hello!
For some time now I have been absolutely fascinated with quantum mechanics. Unfortunately for me, I am well...

Aug1314 10:32 PM
atyy

3 
244 
I have some questions about this paper:http://users.phys.psu.edu/~radu/extra_strings/freedman_sigma_model.pdf
In...

Aug1314 10:17 PM
Greg Bernhardt

1 
240 
Suppose you have λø4 theory and calculate the bare 4point function:
$$...

Aug1314 08:45 PM
geoduck

1 
173 
Hi, I have been trying to get the expression for the transition dipole moment of hydrogen but I am not able to get the...

Aug1314 09:39 AM
Meir Achuz

3 
234 
According to my teacher, for any two operators A and B, the commutators
=df(A)/dA
and =df(B)/dB
He did not give any...

Aug1214 10:46 PM
strangerep

8 
262 
I have read contrasting things about the issue.
Can you explain briefly why the assumption of discrete space and...

Aug1214 07:51 PM
bhobba

24 
791 
Author: ZapperZ
Originally posted on Feb2814
One of the most spectacular theoretical description that Einstein...

Aug1214 05:00 PM
davenn

2 
207 
What is Quantum Entanglement, and what does it do?
I attempted at learning via online articles.

Aug1214 03:29 PM
BiGyElLoWhAt

17 
446 
Hello,
The oneelectron universe hypothesis, commonly associated with Richard Feynman when he mentioned it in his...

Aug1214 03:05 PM
jtbell

3 
285 
Author: ZapperZ
Originally posted on Jan1713
{I have seen this type of question or scenario being presented on PF...

Aug1214 02:12 PM
Greg Bernhardt

0 
175 
When a particle's position is measured, does the wavefunction collapse to the eigenstate of the measurement (a delta...

Aug1214 12:28 PM
jostpuur

89 
2,363 
Hi everyone,
This is my first post. Years ago I read in a science magazine that (at least according to a certain...

Aug1214 09:46 AM
mjsd

7 
417 
Hello Forum,
When a system is in a particular state, indicated by a A>, we can use any basis of eigenvectors to...

Aug1214 04:31 AM
tom.stoer

26 
537 
One of the problems in QM i frequently encounter in all textbooks is the shifting of the wall problem which goes like...

Aug1214 02:08 AM
tom.stoer

14 
366 
Hi. I will give you a question I have looked at and then tell you where I am confused.
The wavefunction for a...

Aug1114 06:40 PM
bhobba

7 
305 
Dear PF:
I'm currently working in a problem that has had me stranded for several weeks now. The problem reads as...

Aug1114 01:00 PM
Jilang

15 
295 
Hi,
I have read that quantum fluctuations have created our universe through the Big Bang. The issue that I didn't...

Aug1114 09:42 AM
bgq

2 
263 
I considered the covariance of 2 spin 1/2 as a non linear operator : A\otimes BA\Psi\rangle\langle\PsiB.
The...

Aug1114 08:48 AM
jk22

9 
1,173 
Hello
I am trying to solve the dirac equation. I want to solve the dirac eq say for 2 particle system. therefore i...

Aug1014 09:31 PM
nakulphy

5 
388 
I want to discuss the theorem proved in the article "Quantum states and generalized observables: a simple proof of...

Aug1014 01:40 PM
naima

37 
3,943 
Does having a momentum cutoff require space to be discretized?
As an analogy, suppose you put your fields in a box...

Aug1014 12:08 AM
atyy

1 
250 
So based on String theory, when doing a Double Slit Style Experiment when an observation is made it is a particle and...

Aug914 09:49 PM
bhobba

2 
188 
Hi guys,
Sorry if this isn't quite the right place to post this, but I have a few conceptual questions that I'd...

Aug914 08:05 PM
"Don't panic!"

18 
624 
Hi,
I had a look at Susskinds explanation about QM and this is pretty strange from my point of view.
Video:...

Aug914 07:45 PM
Omega0

2 
213 
Hallo everybody.
Foreword1: I am an engineer not a physicist
Foreword2: I am reading a paper about diffusion MRI who...

Aug914 07:40 PM
bhobba

1 
235 
Is it purely coincidental that the internal symmetry related flavor quantum numbers(like isospin and weak isospin) and...

Aug914 05:29 PM
dextercioby

1 
254 
Suppose we want to get eigenfunctions of a OneParticle Hamiltonian corresponding to one of its eigenvalues, say E, in...

Aug914 02:44 PM
WannabeNewton

1 
233 
The spin of an arbitrarily oriented electron precesses in the presence of a magnetic field (see Feyman lectures 107)....

Aug914 08:31 AM
43arcsec

11 
451 
is it true that 'Spread of Energy in Space' determines 'Spread of Matter in Space', at given point in time?
i am...

Aug914 02:03 AM
neomahakala108

10 
299 
"E2" Quadrupole decay rate
Problem Statement
Obtain the angular dependence of the rate for the emission to a single...

Aug914 01:24 AM
MisterX

1 
326 
In Feynman's famous book QED, he repeatedly reminds us that we must include the possibilities of photons traveling...

Aug814 08:42 PM
WannabeNewton

3 
315 
I recognize the practical aspects of this would be absurd, but I must admit the premise of what it would take to put a...

Aug814 07:50 PM
bhobba

21 
1,460 
Suppose I want an expectation value of a harmonic oscillator wavefunction, then in what way will I write the Hermite...

Aug814 03:13 AM
Mniazi

4 
260 
Hi again,
Another, possibly trivial, question.
In quantum dynamics we consider maps containing the evolution of a...

Aug714 08:22 PM
bhobba

3 
180 
Hi,
In many quantum physics books I see questions such as "what is the spinorbit interaction in this case?" Sorry...

Aug714 03:56 AM
DrClaude

1 
301 
Is there a resonant frequency of light? I was just wondering because the higher the frequency of light, the higher the...

Aug714 03:38 AM
Rob Hoff

5 
359 
One theory I've heard and which I find interesting is that entanglement between any pair of twostate systems could be...

Aug614 03:26 PM
Jonathan Scott

3 
371 
I am curious what a photon looks like if we could observe it pass through space. It's also supposed to be oscillation...

Aug614 05:40 AM
Geometry_dude

39 
1,485 
I donot understand why we quantize the field by defining the commutation relation.What's that mean?And what's the...

Aug614 02:59 AM
bhobba

2 
260 
Hi all,
Just a quick theory based question regarding the Zeeman Effect.
The effect of the applied magnetic field...

Aug514 03:06 PM
WannabeNewton

1 
244 