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Experimental Demonstration of Direct Path State Characterization by strongly measuring Weak Values

January 7, 2017 Published by

We developed a measurement scheme, used in a matter-wave interferometric experiment, in which the neutron path system’s quantum state was characterized via direct measurements using both strong and weak interactions. Experimental evidence is given that strong interactions outperform weak ones for tomographic accuracy. Our results are not limited to neutron interferometry, but can be used in a wide range of quantum systems. T. Denkmayr et al., Physical Review Letters 118, 010402 (2017)

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Mixed State Uncertainty Relations

September 30, 2016 Published by

In the last decade, several universally valid forms of error-disturbance uncertainty relations were derived for completely general quantum measurements for arbitrary states.  An optimal form for spin measurements for some pure states was established recently. However, the bound in his inequality is not stringent for mixed states. Masanao Ozawa derived a new bound tight in the corresponding mixed state case, which was tested by our group. We experimentally observed the attainability of the new bound. B. Demirel et al., Physical Review Letters 117, 140402 (2016)

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Review paper published

March 11, 2016 Published by

The validity of quantum-mechanical predictions has been confirmed with a high degree of accuracy in a wide range of experiments. Although the statistics of the outcomes of a measuring apparatus have been studied intensively, little has been explored and is known regarding the accessibility of quantum dynamics. Sponar et al., Atoms 4, 11 (2016)

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Uncertainty Relation in Quantum Information Theory

July 13, 2015 Published by

Uncertainty relation in quantum information theory publish in PRL and relieved an Editor’s Suggestion! Information is a key quantity in science and plays a significant role in many economic sectors such as communication technologies, cryptography, or data storage. In quantum communication and information technology the transfer and encryption of information is studied. Sulyok et al., Phys. Rev. Lett115, 030401 (2015)

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Experimental Demonstration of a generalized Error-Disturbance Uncertainty Relation

January 16, 2012 Published by

Heisenberg’s uncertainty principle. is certainly one of the most famous foundations of quantum physics. According to this principle, not all properties of a quantum particle are determined with arbitrary accuracy. In the early days of quantum theory, this has often been justified by the notion that every measurement inevitably recoils the quantum particle, which disturbs the results of any further measurements. This, however, turns out to be an oversimplification. In our neutron polarimetric experiment different sources of quantum uncertainty could now be distinguished, validating theoretical results of an error-disturbance uncertainty relation proposed by Masanao Ozawa. Y. Hasegawa et al., Nature Physics 8, 185-189 (2012)