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Experiment towards continuous-variable entanglement swapping: Highly correlated four-partite quantum state

Oliver Glöckl·Stefan Lorenz·Christoph Marquardt·Joel Heersink·Michel Brownnutt·Christine Silberhorn·Qing Pan·Peter van Loock·Natalia Korolkova·Gerd Leuchs
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Abstract

We present a protocol for performing entanglement swapping with intense pulsed beams. In a first step, the generation of amplitude correlations between two systems that have never interacted directly is demonstrated. This is verified in direct detection with electronic modulation of the detected photocurrents. The measured correlations are better than expected from a classical reconstruction scheme. In the entanglement swapping process, a four--partite entangled state is generated. We prove experimentally that the amplitudes of the four optical modes are quantum correlated 3 dB below shot noise, which is due to the potential four--party entanglement.

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Oliver Glöckl, Stefan Lorenz, Christoph Marquardt, Joel Heersink, Michel Brownnutt, Christine Silberhorn, Qing Pan, Peter van Loock, Natalia Korolkova, Gerd Leuchs. 2003-05-30. Experiment towards continuous-variable entanglement swapping: Highly correlated four-partite quantum state. https://doi.org/10.1103/physreva.68.012319

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