Solution
= Solution
The <trace distance> and <quantum fidelity>, in the unsquared convention, are
$$
\boxed{D(\rho,\sigma)=\frac12\|\rho-\sigma\|_1},
\qquad
\boxed{F(\rho,\sigma)
=\operatorname{Tr}\sqrt{\sqrt\rho\,\sigma\sqrt\rho}}.
$$
= Solution
The <trace distance> and <quantum fidelity>, in the unsquared convention, are
$$
\boxed{D(\rho,\sigma)=\frac12\|\rho-\sigma\|_1},
\qquad
\boxed{F(\rho,\sigma)
=\operatorname{Tr}\sqrt{\sqrt\rho\,\sigma\sqrt\rho}}.
$$