Measurement of purity, the simplest nonlinear functional of the density matrix

Tohru Tanaka, Hiromichi Nakazato

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


After reviewing the earlier ideas to measure the purity of a quantum system, a new scheme for the measurement of purity is presented, which aims at providing a simple, direct and efficient procedure without resorting to quantum state tomography. The scheme is also illustrated in the Bloch-vector representation for a two-level quantum system (qubit) and for a general D-level quantum system. As a variant, a simple example implemented in a one-dimensional scattering process to measure the purity of the target qubit is also given.

Original languageEnglish
Article number1440009
JournalOpen Systems and Information Dynamics
Issue number1-2
Publication statusPublished - 2014 Jun

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Mathematical Physics


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