(1) Dipartimento di Fisica dell'Università degli Studi di Milano, via Celoria 16, 20133 Milano, Italy
Abstract:
We address quantum state reconstruction for d-dimensional
systems based on measuring, on the system of interest and a
probe, of a single entangled observable defined on the bipartite
system/probe Hilbert space. We show that the statistics of the
measurement and the knowledge of the probe preparation suffice to
reliably reconstruct the density matrix of the system, as well
as the expectation value of any desired operator, including those
not corresponding to observable quantities. The statistical
robustness of the reconstruction is examined and a method is
developed to minimize statistical errors by tuning the probe
preparation. Numerical simulations of the whole reconstruction
procedure are also presented for qubit systems.