Editing Full Quantum state tomography with Linear Inversion (section)

==Outline==
Quantum state tomography attempts to characterize an unknown state ρ by measuring its components, usually in the Pauli basis or a different selected basis of measurement operators. Multiple identical copies of the quantum state are required as different measurements need to be performed on each copy. To fully reconstruct the density matrix for a mixed state, this method is used. This procedure can be used to completely characterize an unknown apparatus.

This method consists of the following steps:

* An unknown state is prepared multiple times so as to create many copies.
* The experimenter picks a basis of measurement operators.
* The measurement corresponding to each measurement operator in the selected basis is taken multiple times. This is used to approximate the probability of measuring the state in the value corresponding to the measurement operator.
* With the knowledge of the probabilities and the chosen measurement basis, the density matrix of the quantum state is calculated using matrix inversion.