### GR9277 #50

Posted:

**Mon Jul 22, 2013 7:51 am**In what book do I find the theory behind this qs.? The qs is: http://grephysics.net/ans/9277/50

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Posted: **Mon Jul 22, 2013 7:51 am**

In what book do I find the theory behind this qs.? The qs is: http://grephysics.net/ans/9277/50

Posted: **Mon Jul 22, 2013 10:15 pm**

Shankar

Posted: **Mon Jul 22, 2013 11:38 pm**

Well any qm textbook would demobstrate this fact basically.

Anyway qm is also known as matrix mechanics for a reason. The question is basically asking when does the order of observations not matter i.e. when is AB\psi=BA\psi for ALL \psi?

Anyway qm is also known as matrix mechanics for a reason. The question is basically asking when does the order of observations not matter i.e. when is AB\psi=BA\psi for ALL \psi?

Posted: **Tue Jul 23, 2013 9:47 am**

Will I find it in Griffiths?

Posted: **Tue Jul 23, 2013 11:26 am**

Sure.collectedsoul wrote:Will I find it in Griffiths?

In fact you don't even need a quantum mechanics text. All you need is a linear algebra text.