Figure 4: Performance of the MPS–SVT algorithm for W-states.
We are not limited to few ions and demonstrate convergence for up to 20 ions—even higher number of ions are easily accessible due to the MPS alteration of the SVT method, demonstrating the efficiency of our approach. We mimic experimental noise by adding Gaussian distributed random numbers with zero mean to the local expectations 
and show results for n=4,000 MPS–SVT iterations. Plot shows fN,n=|〈φ|yn〉|2 as a function of the number of ions, N, for no noise (dots) and Gaussian noise (densities obtained from 100 realizations for each N, arrows indicate mean) with a s.d. 0.005 (blue; only even values of N plotted for clarity) and 0.01 (black, odd N).
