- #1
Nusc
- 760
- 2
Homework Statement
I need to find the expectation value for E but I don't know how b acts on the vacuum state.
Homework Equations
[tex]
b = \int dt \phi^{*}(t) \hat{{\cal E}}_{in}(t)
[/tex]
[tex]
| \psi(t)\rangle = b^\dagger| 0\rangle
[/tex]
The Attempt at a Solution
[tex]
\langle \psi(t) | \hat{{\cal E}}^\dagger\hat{{\cal E}}| \psi(t)\rangle =
[/tex]