I have an observable denoted by $C$, related to a complex potential $B$ by :
$$ C= \bar{B}B ,$$
where $B$ is a complex potential. I know that $ \left. C \right|_0 =C_0 $, a known constant, where the evaluation at $_0$ denotes an equilibrium \ reference state. From this, I can not make any conclusions on $\left. B \right|_0$, or $ \left. \bar{B} \right|_0$ can I ?
Thanks.