- #1

- 8

- 0

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter xdeimos
- Start date

- #1

- 8

- 0

- #2

- 8

- 0

1. why <x> is squeez between ψ* and ψ what we doing this?

2. for <p> [h/i d/dx ] is sqeeze between ψ* and ψ why is that?

3. if you put latter operator between ψ* and ψ what is going to happen?

thank you

- #3

bhobba

Mentor

- 9,687

- 2,766

Its easier to see in the Dirac notation - E(A) = <u|A|u>

But that is only a special case valid for so called pure states - the full rule is E(A) = Trace(PA) where P is a positive operator of unit trace which is the correct definition of a quantum state - pure states |u><u| are a special case. For pure states Trace(|u><u| A) = <u|A|u>

As to why that formula check out Gleason's Theorem:

http://kof.physto.se/theses/helena-master.pdf [Broken]

Thanks

Bill

But that is only a special case valid for so called pure states - the full rule is E(A) = Trace(PA) where P is a positive operator of unit trace which is the correct definition of a quantum state - pure states |u><u| are a special case. For pure states Trace(|u><u| A) = <u|A|u>

As to why that formula check out Gleason's Theorem:

http://kof.physto.se/theses/helena-master.pdf [Broken]

Thanks

Bill

Last edited by a moderator:

- #4

Khashishi

Science Advisor

- 2,815

- 493

The sign of the complex part of the wavefunction also has no real significance. Multiplying a number by its complex conjugate gives the absolute value squared. This is a handy mathematical trick, but there's no reason other than convention to put the conjugate on the left factor or the right factor.

Share: