• DOI:10.1103/PhysRevLett.109.160502
• Corpus ID: 13447990

Detection of multiparticle entanglement: quantifying the search for symmetric extensions.

@article{Brando2012DetectionOM,
  title={Detection of multiparticle entanglement: quantifying the search for symmetric extensions.},
  author={Fernando G. S. L. Brand{\~a}o and Matthias Christandl},
  journal={Physical review letters},
  year={2012},
  volume={109 16},
  pages={
          160502
        }
}

• F. Brandão, M. Christandl
• Published 28 May 2011
• Physics
• Physical review letters

We provide quantitative bounds on the characterization of multiparticle separable states by states that have locally symmetric extensions. The bounds are derived from two-particle bounds and relate to recent studies on quantum versions of de Finetti's theorem. We discuss algorithmic applications of our results, in particular a quasipolynomial-time algorithm to decide whether a multiparticle quantum state is separable or entangled (for constant number of particles and constant error in the norm induced by one-way local operations and classical communication, or in the Frobenius norm). Our results provide a theoretical justification for the use of the search for symmetric extensions as a test for multiparticle entanglement.