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scarecrow
Oct19-06, 07:52 PM
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???

Epicurus
Oct19-06, 10:44 PM
If you worked out these explicitly this should be pretty clear. The potential term commutes with x but not with p.

Meir Achuz
Oct20-06, 10:09 AM
I don't think [H,x]=0.

reilly
Oct23-06, 09:59 PM
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,