14-Qubit entanglement: creation and coherence

Phys Rev Lett. 2011 Apr 1;106(13):130506. doi: 10.1103/PhysRevLett.106.130506. Epub 2011 Mar 31.


We report the creation of Greenberger-Horne-Zeilinger states with up to 14 qubits. By investigating the coherence of up to 8 ions over time, we observe a decay proportional to the square of the number of qubits. The observed decay agrees with a theoretical model which assumes a system affected by correlated, Gaussian phase noise. This model holds for the majority of current experimental systems developed towards quantum computation and quantum metrology.