Efficient estimation 8 Efficiency 4 Estimation 4 Quantum efficiency 4 Quantum process tomography 4 Sampling 4 Tomography 4 EFFICIENT ESTIMATION 3 ESTIMACION EFICIENTE 3 LINEAR REGRESSION 3 MINIMOS CUADRADOS PESADOS 3 REGRESION LINEAL 3 ROBUSTEZ 3 ROBUSTNESS 3 WEIGHTED LEAST SQUARES 3 Adaptive estimation 2 Brakdown point 2 Density matrix 2 Diagonal elements 2 Efficient estimator 2 Efficient method 2 Equivariant estimators 2 Finite sample efficiency 2 Finite samples 2 Initial estimators 2 Kullback–Leibler divergence 2 Linear modeling 2 MM-estimator 2 MM-estimators 2 Matrix elements 2