 #1
 3
 0
Hi all,
This is the problem I want to share with you.
We have the hamiltonian H=aP+bm, which we are commuting with the position x and take:
[x,H]=ia, (ħ=1)
Ok. Now if we take, instead of x, the operator
X=Π_{+} x Π_{+} +Π_{}xΠ_{}
where Π_{±} projects on states of positive or negative energy
the result will be:
[X,H]=iP/H
Can somebody explain me how this result comes out.
Thanks in advance
QC
This is the problem I want to share with you.
We have the hamiltonian H=aP+bm, which we are commuting with the position x and take:
[x,H]=ia, (ħ=1)
Ok. Now if we take, instead of x, the operator
X=Π_{+} x Π_{+} +Π_{}xΠ_{}
where Π_{±} projects on states of positive or negative energy
the result will be:
[X,H]=iP/H
Can somebody explain me how this result comes out.
Thanks in advance
QC
Attachments

14.8 KB Views: 358