Back to Publications


Experimental demonstration of direct path state characterization by strongly measuring weak values in a matter-wave interferometer

Physical review letters 118(1)
Denkmayr, T.Geppert, H.Lemmel, H.Waegell, M.Dressel, J. Hasegawa, Y.Sponar, S. Atominstitut,
TU Wien, Vienna, Austria

Institut Laue-Langevin,
Grenoble, France

Institute for Quantum Studies,
Chapman University,
Orange, CA, USA

Schmid College of Science and Technology,
Chapman University,
Orange, CA, USA
2017 Physics

A novel method was recently proposed and experimentally realized for characterizing a quantum state by directly measuring its complex probability amplitudes in a particular basis using so-called weak values. Recently Vallone and Dequal showed theoretically that weak measurements are not a necessary condition to determine the weak value [Phys. Rev. Lett. 116, 040502 (2016)].

Here we report 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. Our results are not limited to neutron interferometry, but can be used in a wide range of quantum systems.

The article was published in: Physical review letters 118(1): 010402.

Full article

This work was supported (in part) by the Fetzer Franklin Fund of the John E. Fetzer Memorial Trust.