Mainz 2017 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 32: Quantum Information: Concepts and Methods V

Q 32.3: Vortrag

Mittwoch, 8. März 2017, 15:00–15:15, P 2

Detection of quantum correlations without quantum discord — •Semjon Köhnke, Elizabeth Agudelo, Melanie Mraz, Oskar Schlettwein, Werner Vogel, and Boris Hage — Institut für Physik, Universität Rostock, Germany

Currently a variety of different nonclassicality criteria are discussed. They should classify whether a quantum state has a classical character or is governed by quantum phenomena.

For testing nonclassicality criteria phase diffused squeezed states were successfully used [1]. These states are a mixture of squeezed states with a stochastically distributed phase. In our experiment we go a step further. We produce an entangled state out of two squeezed fields which interfere on a 50/50 beam splitter. Using phase diffusion at one of the outputs gives us a fully randomized phase relation between both of them. Thereby the entanglement gets destroyed.

To identify quantum correlation effects the quantum discord is widely spread as universal indicator. Though this indicator fails and does not reveal the nonclassical correlations from our experiment. In contrast using the sampling formula of the regularized Glauber-Sudarshan P function [2] we obtain a quasiprobability distribution which uncovers any quantum correlations, going beyond quantum entanglement and quantum discord.

[1] Schnabel et al., Phys. Rev. A 79, 022122 (2009).

[2] Vogel et al., Phys. Rev. A 87, 033811 (2013).