Harmonic Oscillator Operators?

Click For Summary

Discussion Overview

The discussion revolves around the commutation relations between the position operator (x), momentum operator (p), and the harmonic oscillator Hamiltonian (H) in quantum mechanics. Participants explore why the position operator commutes with the Hamiltonian while the momentum operator does not, delving into the implications of these relationships.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • One participant states that the commutator [x, H] equals zero, implying that x commutes with H.
  • Another participant asserts that the potential term in the Hamiltonian commutes with x but not with p, suggesting a reason for the differing commutation relations.
  • A different participant challenges the claim that [H, x] equals zero, indicating a disagreement on this point.
  • Reilly Atkinson mentions that the commutator of x with the kinetic energy term is not zero and is proportional to p, further complicating the discussion on commutation.

Areas of Agreement / Disagreement

Participants express disagreement regarding the commutation relations, particularly whether [H, x] equals zero. Multiple competing views remain on the nature of these commutators.

Contextual Notes

There are unresolved aspects regarding the definitions of the operators and the specific forms of the Hamiltonian being discussed, which may affect the conclusions drawn about the commutation relations.

scarecrow
Messages
139
Reaction score
0
I worked these problems out:

[x, H] = xH - Hx = 0

[p, H] = pH - Hp = non-zero

H is the harmonic oscillator Hamilitonian, x and p are the position and momentum operators, respectively.

My question is, why doesn't p commute with H, but x does?
 
Physics news on Phys.org
If you worked out these explicitly this should be pretty clear. The potential term commutes with x but not with p.
 
I don't think [H,x]=0.
 
The commutator of X with the KE, p*p/2m, is not zero; the commutator is proportional to p, the momentum.
Regards,
Reilly Atkinson

Harmonic oscillator commutators are discussed in almost any QM text,
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K