Quantum Mechanics: Probability of the result h-bar/2 if Sy is measured

[bbnl1990]

Homework Statement

http://dl.dropbox.com/u/24280471/Question.PNG
http://dl.dropbox.com/u/24280471/Answer.PNG

Homework Equations

Isn't the probability of measuring h-bar/2 the same as the probability of finding the particle in the state ψ₊? Since Syψ₊ = (h-bar/2)Syψ₊.

The Attempt at a Solution

(Sorry, don't know how to use LaTex.)
http://dl.dropbox.com/u/24280471/Attempt.PNG

 

[TSny]

Isn't the probability of measuring h-bar/2 the same as the probability of finding the particle in the state ψ₊?

Yes, your solution is correct. The answer in the problem statement is incorrect. They should have left out the matrix Sy in the calculation of the probability. Note that the probability must be a dimensionless number, but they are getting something that has the dimensions h².

 

[bbnl1990]

Yes, your solution is correct. The answer in the problem statement is incorrect. They should have left out the matrix Sy in the calculation of the probability. Note that the probability must be a dimensionless number, but they are getting something that has the dimensions h2.

Thank you for your reply!