Author Correction: Demonstration of Shor’s factoring algorithm for N = 21 on IBM quantum processors

The peak outcomes should be 011 and 101, corresponding to the integers 3 and 5. Both of these integers give the correct period r = 3 when continued fractions are performed, leading to the successful factorization of N = 21. In the original version of the paper only the integer 5 was identified and shown to state the correct period. The original Figure 7 and accompanying legend appear below. Figure 7 Results of the complete quantum order-finding routine for N = 21 and a = 4. On each processor, the circuit was executed 8192 × 100 times with measurement error mitigation. The error bars represent 95% confidence intervals around the mean value of each histogram bin (see Supplementary information IV ). The simulator probabilities show the ideal case. Full size image