Assessing the progress of trapped-ion processors towards fault-tolerant quantum computation by Bermudez, A, Xu, X, Nigmatullin, R, O’Gorman, J, Negnevitsky, V, Schindler, P, Monz, T, Poschinger, U, Hempel, C, Home, J, Schmidt-Kaler, F, Biercuk, M, Blatt, R, Benjamin, S, Müller, M