Hi guys, I'm having some trouble with bra-ket algebra.(adsbygoogle = window.adsbygoogle || []).push({});

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.

**Physics Forums - The Fusion of Science and Community**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Basic bra-ket algebra

Loading...

Similar Threads - Basic algebra | Date |
---|---|

I Two coherent sources | Yesterday at 10:20 PM |

I For a particle on a sphere, is zero energy possible? | Saturday at 12:56 PM |

I Generalized coordinates basic question | Feb 24, 2018 |

A States in usual QM/QFT and in the algebraic approach | Feb 14, 2018 |

What's the energy-spread of the quantum Universe state? | Feb 13, 2018 |

**Physics Forums - The Fusion of Science and Community**