- #1
jrand26
- 11
- 0
Hi guys, I'm having some trouble with bra-ket algebra.
For example, our lecturer did on the board, <Sx+|Sz|Sx+>
So what I would do is, ignoring any factors of 1/sqrt(2) or 1/2 or hbar.
Sx+ = |+> + |->
Sz = |+><+|-|-><-|
=> ( |+> + |-> )(|+><+|-|-><-|)( |+> + |->)
This is where I get stuck, the lecturer goes straight from this to,
(<+| + <-|)(|+> - |->)
When I try to expand it out, for the first two terms, I get stuck at
|+> * |+><+|-|-><-| = |+>|+> <+|-|-> <-|+> ??
I can see that the |+> can go with the <-| at the end, but does it go onto the expectation as well? How does that work?
Does |+> <+|-|-> = <+|+>|-|-> ?
That doesn't look right to me. Any help is appreciated.
For example, our lecturer did on the board, <Sx+|Sz|Sx+>
So what I would do is, ignoring any factors of 1/sqrt(2) or 1/2 or hbar.
Sx+ = |+> + |->
Sz = |+><+|-|-><-|
=> ( |+> + |-> )(|+><+|-|-><-|)( |+> + |->)
This is where I get stuck, the lecturer goes straight from this to,
(<+| + <-|)(|+> - |->)
When I try to expand it out, for the first two terms, I get stuck at
|+> * |+><+|-|-><-| = |+>|+> <+|-|-> <-|+> ??
I can see that the |+> can go with the <-| at the end, but does it go onto the expectation as well? How does that work?
Does |+> <+|-|-> = <+|+>|-|-> ?
That doesn't look right to me. Any help is appreciated.