What kind of question is it?


by roshan2004
Tags: kind
roshan2004
roshan2004 is offline
#1
Aug13-10, 01:40 AM
P: 139
In my terminal exam I was asked to prove it that the parity operation commutes with Hermitian operator? I wonder how can we show that? coz we can only show that the parity operator is hermitian? We haven't got the value of hermitian operator at all?
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Petr Mugver
Petr Mugver is offline
#2
Aug13-10, 02:07 AM
P: 280
On wave functions the parity operator acts something like

[tex]P\psi(x)=\eta\psi(-x)[/tex]

where \eta is a phase factor independent of x. Now it should be easy to prove all the commutation relations you need.
roshan2004
roshan2004 is offline
#3
Aug13-10, 02:20 AM
P: 139
Pls Can you show it to me how?

Petr Mugver
Petr Mugver is offline
#4
Aug13-10, 02:36 AM
P: 280

What kind of question is it?


I can try, but first you have to tell me which is the operator you want to calculate the commutator with parity.
roshan2004
roshan2004 is offline
#5
Aug13-10, 03:17 AM
P: 139
Hermitian operator
Petr Mugver
Petr Mugver is offline
#6
Aug13-10, 04:24 AM
P: 280
Quote Quote by roshan2004 View Post
Hermitian operator
It's not enough. For example, P does not commute with the coordinates x or the momenta p (these anticommute with parity), but it commutes with orbital agular momentum or spin...
roshan2004
roshan2004 is offline
#7
Aug13-10, 07:23 AM
P: 139
So, wasn't the question a wrong one?
the_house
the_house is offline
#8
Aug13-10, 08:19 AM
P: 133
If it really implied that the parity operator commutes with all Hermitian operators, then yes, it was wrong.


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