Abstract: The present disclosure provides a discriminator, comprising a signal interface configured to receive an input signal that is read out from a quantum qudit comprising a number d of states, a multi-state discriminator comprising a number of weighted integration units, wherein the number of weighted integration units is equal to (d?1), a one-vs-one classifier that is coupled to the weighted integration units, and a number of pairwise difference units that in addition couple the one-vs-one classifier indirectly with the weighted integration units, wherein the number of pairwise difference units is (d?1)*(d?2)/2, wherein the one-vs-one classifier is configured to determine a state of the quantum qudit based on the output of the weighted integration units and the pairwise difference units. The present disclosure further provides a multi-qudit multi-state discriminator and a respective method.