Remote creation of hybrid entanglement between particle-like and wave-like optical qubits


The wave–particle duality of light has led to two different encodings for optical quantum information processing. Several approaches have emerged based either on particle-like discrete-variable states (that is, finite-dimensional quantum systems) or on wave-like continuous-variable states (that is, infinite-dimensional systems). Here, we demonstrate the generation of entanglement between optical qubits of these different types, located at distant places and connected by a lossy channel. Such hybrid entanglement, which is a key resource for a variety of recently proposed schemes, including quantum cryptography and computing, enables information to be converted from one Hilbert space to the other via teleportation and therefore the connection of remote quantum processors based upon different encodings. Beyond its fundamental significance for the exploration of entanglement and its possible instantiations, our optical circuit holds promise for implementations of heterogeneous network, where discrete- and continuous-variable operations and techniques can be efficiently combined.

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Figure 1: Measurement-induced hybrid entanglement.
Figure 2: Experimental quantum state tomography.
Figure 3: Experimental quantum states from separable to maximally entangled.


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The authors thank N. Sangouard for discussions and V. D'Auria and F. A. S. Barbosa for their valuable contributions in the early stage of the experiment. This work is supported by the ERA-Net CHIST-ERA (QScale) and by the European Research Council (ERC) starting grant HybridNet. K.H. acknowledges support from the Foundation for the Author of National Excellent Doctoral Dissertation of China (PY2012004) and the China Scholarship Council. C.F. and J.L. are members of the Institut Universitaire de France.

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J.L. and O.M. conceived the experiment. O.M., K.H., J.Liu and H.L.J. carried out the experiment and analysed the data, under the supervision of J.L. O.M, K.H., H.L.J., C.F. and J.L. contributed to discussing the implementation and the results. O.M., K.H. and J.L. wrote the manuscript.

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Correspondence to Julien Laurat.

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Morin, O., Huang, K., Liu, J. et al. Remote creation of hybrid entanglement between particle-like and wave-like optical qubits. Nature Photon 8, 570–574 (2014).

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