Experimental test of an entropic measurement uncertainty relation for arbitrary qubit observables

Bülent Demirel (1) , Stephan Sponar (1) , Alastair A. Abbott (2) , Cyril Branciard (2) , Yuji Hasegawa (1)

1 TU Wien - Vienna University of Technology = Technische Universität Wien
2 NEEL - NPSC - Nanophysique et Semiconducteurs

A tight information-theoretic measurement uncertainty relation is experimentally tested with neutron spin-1/2 qubits. The noise associated to the measurement of an observable is defined via conditional Shannon entropies and a tradeoff relation between the noises for two arbitrary spin observables is demonstrated. The optimal bound of this tradeoff is experimentally obtained for various non-commuting spin observables. For some of these observables this lower bound can be reached with projective measurements, but we observe that, in other cases, the tradeoff is only saturated by general quantum measurements (i.e., positive-operator valued measures), as predicted theoretically.

Domaines: Physique [physics]; Physique Quantique [quant-ph]

Bülent Demirel, Stephan Sponar, Alastair A. Abbott, Cyril Branciard, Yuji Hasegawa. Experimental test of an entropic measurement uncertainty relation for arbitrary qubit observables. New Journal of Physics, 2019, 21, pp.013038. ⟨10.1088/1367-2630/aafeeb⟩. ⟨hal-01927775⟩