2001/09/20 by Christoph Simon, Julia Kempe · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physreva.65.052327
published as Phys. Rev. A, Vol. 65 (5), 052327 (2002) · 4 pages
arxiv created 2001/09/20 · arxiv updated 2009/12/01
How common is large-scale entanglement in nature? As a first step towards addressing this question, we study the robustness of multi-party entanglement under local decoherence, modeled by partially depolarizing channels acting independently on each subsystem. Surprisingly, we find that n-qubit GHZ entanglement can stand more than 55 % local depolarization in the limit of n going to infinity, and that GHZ states are more robust than other generic states of 3 and 4 qubits. We also study spin-squeezed states in the limit n going to infinity and find that they too can stand considerable local depolarization.