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We study generating joint measurements by operating on the input quantumstate with a broadcasting channel followed by local measurements on the twooutputs of the broadcasting channel. Although, due to perfect broadcasting orcloning being impossible, this scheme cannot generate perfect joint observablesfor all pairs of quantum observables, we study for what intended jointobservables and local measurements this procedure can be carried out. For localsharp observables this is always possible as long as the intended jointobservable is dominated by the tensor product of the local sharp observables.This result excludes the case of joint measurements of continuous sharpobservables with themselves which we indeed show to be impossible to begenerated through broadcasting. We also derive necessary and sufficientconditions for the success of the broadcasting scheme for local noisyobservables and intended joint observables which are easily checked when thelocal observables are convex mixtures of sharp observables and white noise. Wealso study broadcasting of local fuzzy observables in the presence ofsymmetries. Finally we introduce the scenario of measuring joint observableswhere we have access to broadcasting, local measurements and post-processingand characterize the most resourceful local measurements in this setting.

Joint measurements through quantum broadcasting