Quantifying nonclassicality: Global impact of local unitary evolutions

Salvatore Giampaolo, Alexander Streltsov, Wojciech Roga, Dagmar Bruß, Fabrizio Illuminati

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


We show that only those composite quantum systems possessing nonvanishing quantum correlations have the property that any nontrivial local unitary evolution changes their global state. We derive the exact relation between the global state change induced by local unitary evolutions and the amount of quantum correlations. We prove that the minimal change coincides with the geometric measure of discord (defined via the Hilbert-Schmidt norm), thus providing the latter with an operational interpretation in terms of the capability of a local unitary dynamics to modify a global state. We establish that two-qubit Werner states are maximally quantum correlated, and are thus the ones that maximize this type of global quantum effect. Finally, we show that similar results hold when replacing the Hilbert-Schmidt norm with the trace norm.
Original languageEnglish
Article number012313
Number of pages5
JournalPhysical Review A
Issue number1
Publication statusPublished - 16 Jan 2013
Externally publishedYes


  • composite quantum systems
  • quantum correlations
  • Hilbert-Schmidt norm
  • trace norm
  • nontrivial local evolution


Dive into the research topics of 'Quantifying nonclassicality: Global impact of local unitary evolutions'. Together they form a unique fingerprint.

Cite this