In equation (12), there is a small error in the definition of the Holevo Cramér Rao Bound, which should be written (for the notation see the original article.(Equation Presented).where the second term was written as WImZ 1, in the original article. All the remaining results are unchanged. The bounds in equation (15) are still correct, but need further clarifications.clarifications. Indeed equation (15) is justified by the following chain of inequalities.(Equation Presented). o̧pyright 2020 The Author(s). Published by IOP Publishing Ltd on behalf of SISSA Medialab srl.