Bra-ket Notation (5 minutes)

  • Draw a Stern-Gerlach experiment on the board that makes use of S.G. devices in the x-direction and the y-direction.
  • Next to the outputs for each Stern-Gerlach device, write down the kets that represent the states that come out of each output. After this, students should now have seen the ket representation of spin up and spin down in the x,y, and z direction.
  • Remind students that the term inside the ket is strictly representative. That is, you can put whatever you want inside the ket to represent a particular state as long as you are consistent. Be sure to choose one kind of representation to resolve the notation the class will use.
Several Common Representations to Write on the Board

$\vert \: + \rangle $

$\vert\: \frac{\hbar}{2} \rangle$

$\vert\: up \rangle$

$\vert\: \uparrow \rangle$


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