摘要：Classically mixed states. Refer to abstract of this paper. 阅读全文

摘要：Beam Splitter Useful links for beam splitter:https://en.wikipedia.org/wiki/Hong%E2%80%93Ou%E2%80%93Mandel_effect polarizing beam splitters(PBS) refer 阅读全文

摘要：We talk about attainability of classical FIM, in the asymptotic limit, FIM can always be attained:https://en.wikipedia.org/wiki/Maximum_likelihood_est 阅读全文

摘要：Copied from this link For normal $X\sim N(\mu,\sigma^2)$, information matrix is $$\mathcal{I}_1 = \left( \begin{matrix} \frac{1}{\sigma^2} & 0 \ 0 & \ 阅读全文

摘要：$$F=Tr\sqrt{\sqrt{\rho _{\theta}}\left( \rho _{\theta}+\partial \rho _{\theta}d\theta +\partial ^2\rho _{\theta}\frac{d\theta ^2}{2} \right) \sqrt{\rh 阅读全文