Sumiyoshi Abe (Mie University, Japan): Estimating Entanglement

Friday 21 Sept 2018, 14:00 → 16:00 Europe/Budapest

Firstly, a comment is made on the logarithmic derivative (or, quantum score) of a positive definite density matrix  that appears in the quantum Fisher information. Then, the problem of estimating the parameters characterizing  entanglement in a class of the mixed N-qudit states is discussed. The largest value of the lower bound to the error of estimate given by the quantum Fisher information is evaluated in order to examine how the point of separability could be related to it. It is found that this is the case only for 2-qubit. Finally, such largest values are shown to give rise to the universal value of the fidelity independently of the system size.