On estimating operator norm distance, with optimal trace distance estimation when one state is pure

Yupan Liu, Qisheng Wang, Zhan Yu

We investigate the computational complexity of estimating the operator norm distance ${\mathrm{T}}_{\infty }({\rho }_0,{\rho }_1)$, defined via the operator norm $\Vert A{\Vert }_{\infty }={\sigma }_{\max }(A)$, give…