- #1

Jamister

- 58

- 4

the operator that is being measured is

$$ R=N_{1}-N_{2}=a^{\dagger} b+b^{\dagger} a $$.

taking the mode b to be coherent state, we obtain:

$$R=r\left(a^{\dagger} e^{i \phi}+a e^{-i \phi}\right)=\sqrt{2} r q_{\phi}$$.

Now what I don't understand is that what is being measured is discrete photon counts. On the other hand, the spectrum of the operator ##q_{\phi}## is continuous. Therefore, how can obtain ##\langle q_{\phi} \vert \rho \vert q_{\phi} \rangle ## from the measurements?