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arXiv · 2002.10725

Experimental Test of Tight State-Independent Preparation Uncertainty Relations for Qubits

Stephan Sponar·Armin Danner·Kazuma Obigane·Simon Hack·Yuji Hasegawa
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Abstract

The well-known Robertson-Schroedinger uncertainty relations miss an irreducible lower bound. This is widely attributed to the lower bound's state-dependence. Therefore, Abbott \emph{et al.} introduced a general approach to derive tight state-independent uncertainty relations for qubit measurements [Mathematics 4, 8 (2016)]. The relations are expressed in two measures of uncertainty, which are standard deviation and entropy, both functions of the expectation value. Here, we present a neutron optical test of the tight state-independent preparation uncertainty relations for non-commuting Pauli spin observables with mixed spin states. The final results, obtained in a polarimetric experiment, reproduce the theoretical predictions evidently for arbitrary initial states of variable degree of polarization.

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Stephan Sponar, Armin Danner, Kazuma Obigane, Simon Hack, Yuji Hasegawa. 2020-02-25. Experimental Test of Tight State-Independent Preparation Uncertainty Relations for Qubits. https://doi.org/10.1103/physreva.102.042204

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