492 citations · 4.6k across the 77 of their papers we have counts for
3 papers · 1 filter
Separable Measurement Estimation of Density Matrices and its Fidelity Gap with Collective Protocols
E. Bagan, M. A. Ballester, R. D. Gill +2
We show that there exists a gap between the performance of separable and collective measurements in qubit mixed-state estimation that persists in the large sample limit. We charact…
Purity estimation with separable measurements
E. Bagan, M. A. Ballester, R. Munoz-Tapia +1
Given a large number N of copies of a qubit state of which we wish to estimate its purity, we prove that separable-measurement protocols can be as efficient as the optimal joint-me…
Measuring the purity of a qubit state: entanglement estimation with fully separable measurements
E. Bagan, M. A. Ballester, R. Munoz-Tapia +1
Given a finite number of copies of a qubit state we compute the maximum fidelity that can be attained using joint-measurement protocols for estimating its purity. We prove that…