State tomography for two qubits using reduced densities
D�nes Petz, Katalin Mária Hangos, András Szántó, Ferenc Szöllősi · Journal of Physics A Mathematical and General · 2006
The optimal state determination (or tomography) is studied for a composite system of two qubits when measurements can be performed on one of the qubits and interactions of the two qubits can be implemented. The goal is to minimize the number of interactions to be implemented. The algebraic method used in the paper leads to an extension of the concept of mutually unbiased measurements.