Why do I get to a contradiction?

  • Context: Undergrad 
  • Thread starter Thread starter Gjmdp
  • Start date Start date
  • Tags Tags
    Contradiction
Click For Summary
SUMMARY

The discussion centers around the application of the raising operator ##L^+## in quantum mechanics, specifically in the context of the eigenstates ##| l,m \rangle## of the angular momentum operators ##L^2## and ##L_z##. The user expresses confusion regarding the expression $$L_z L^+ | l,m \rangle = \hbar (m+1) L^+ | l,m \rangle$$ and reports encountering a contradiction in their calculations. The consensus among participants indicates that the user likely misunderstood the mathematical framework, leading to the contradiction.

PREREQUISITES
  • Understanding of quantum mechanics, specifically angular momentum operators.
  • Familiarity with the notation and properties of raising and lowering operators.
  • Knowledge of eigenstates and eigenvalues in quantum systems.
  • Proficiency in mathematical manipulation of quantum mechanical expressions.
NEXT STEPS
  • Review the properties of angular momentum operators in quantum mechanics.
  • Study the derivation and application of raising and lowering operators.
  • Learn about eigenstates and eigenvalues, focusing on the implications for quantum systems.
  • Practice solving problems involving the application of operators on quantum states.
USEFUL FOR

Students and professionals in quantum mechanics, particularly those studying angular momentum, as well as educators seeking to clarify concepts related to raising and lowering operators.

Gjmdp
Messages
147
Reaction score
5
I don't understand why LzL+ acting over m is Planck constant(m+1) L+|m>. I 've done it and I've got to a contradiction. Am I doing something wrong?
 
Physics news on Phys.org
Your notaion is difficult to understand. Do you mean
$$
L_z L^+ | l,m \rangle = \hbar (m+1) L^+ | l,m \rangle
$$
with ##L^+## the raising operator and ##| l,m \rangle## an eigenstate of ##L^2## and ##L_z## (with quantum numbers ##l## and ##m##)?

If so, what is the result of ##L^+ | l,m \rangle##?
 
  • Like
Likes   Reactions: vanhees71
Gjmdp said:
I've got to a contradiction. Am I doing something wrong?
Even though you didn't say what exactly have you done, the above is sufficient to conclude that the answer is - yes.
 
  • Like
Likes   Reactions: bhobba
Demystifier said:
Even though you didn't say what exactly have you done, the above is sufficient to conclude that the answer is - yes.
Yup that is very probable. But, there's still the option I didn't understand some of the mathematics, and yet, I may not have done anything wrong.
 
Gjmdp said:
Yup that is very probable. But, there's still the option I didn't understand some of the mathematics, and yet, I may not have done anything wrong.

Then please show us what you have already done.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 2 ·
Replies
2
Views
903
  • · Replies 38 ·
2
Replies
38
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K