Two local observables are sufficient to characterize maximally entangled states of N qubits

Fengli Yan, Ting Gao, Eric Chitambar

Research output: Contribution to journalArticlepeer-review

Abstract

Maximally entangled states (MES) represent a valuable resource in quantum information processing. In N-qubit systems the MES are N-GHZ states [i.e., the collection of |GHZ N =1 √2(|00...0 +|11...1 )] and its local unitary (LU) equivalences. While it is well known that such states are uniquely stabilized by N commuting observables, in this article we consider the minimum number of noncommuting observables needed to characterize an N-qubit MES as the unique common eigenstate. Here, we prove, rather surprisingly, that in this general case any N-GHZ state can be uniquely stabilized by only two observables. Thus, for the task of MES certification, only two correlated measurements are required with each party observing the spin of his or her system along one of two directions.

Original languageEnglish (US)
Article number022319
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume83
Issue number2
DOIs
StatePublished - Feb 22 2011
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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