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Problem with Eigenkets

 
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Oct15-07, 11:16 AM   #1
 

Problem with Eigenkets


1. The problem statement, all variables and given/known data
Show that if an operator A has an eigenket |a> to eigenvalue a then
the adjoint operator A† has an eigenbra <a*| to eigenvalue a*. How
is <a*| related to |a>?


2. Relevant equations
A|a> = |a>a
| >† = < |


3. The attempt at a solution
I actually have no clue where to start this question. I am guessing it has something to do with A† would have an eigenket of |a>†. But I am unsure if this is correct at all.
Would anyone be able to help me get started.
 
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Oct15-07, 11:37 AM   #2
 
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Quote by ConeOfIce View Post
1. The problem statement, all variables and given/known data
Show that if an operator A has an eigenket |a> to eigenvalue a then
the adjoint operator A† has an eigenbra <a*| to eigenvalue a*. How
is <a*| related to |a>?


2. Relevant equations
A|a> = |a>a
| >† = < |


3. The attempt at a solution
I actually have no clue where to start this question. I am guessing it has something to do with A† would have an eigenket of |a>†. But I am unsure if this is correct at all.
Would anyone be able to help me get started.
Take the dagger of (A |a>) This must be equal to the dagger of (a |a>).
 
Oct15-07, 11:47 AM   #3
 
Quote by nrqed View Post
Take the dagger of (A |a>) This must be equal to the dagger of (a |a>).
Ok, I do this. And I also took the dagge of both sides of the equation. So I got
(A|a>)^(dagger) = (|a>a)^dagger which gets

<a|A* = a*<a|.

And using your statement form above I then do
A*<a| = a|a> .
How does this get me any closer to the answer?
 
Oct15-07, 02:18 PM   #4
 
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Problem with Eigenkets


Why would a*=a ??
 
Oct15-07, 05:41 PM   #5
 
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Quote by ConeOfIce View Post
Ok, I do this. And I also took the dagge of both sides of the equation. So I got
(A|a>)^(dagger) = (|a>a)^dagger which gets

<a|A* = a*<a|.
So you are done! You have proved that <a| is an eigenbra of A* with eigenvalue a*!!
And using your statement form above I then do
A*<a| = a|a> .
How does this get me any closer to the answer?
????? What statement from above? I did not say anything lik ethat!
 
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