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Generation of hybrid entanglement of light

Abstract

Entanglement between quantum and classical objects is of special interest in the context of fundamental studies of quantum mechanics and potential applications for quantum information processing. In quantum optics, single photons are treated as light quanta while coherent states are considered the most classical of pure states. Recently, entanglement between a single photon and a coherent state in a free-travelling field was identified as a useful resource for optical quantum information processing. However, the extreme difficulty involved in generating such states was highlighted, as it requires clean cross-Kerr nonlinearities. Here, we devise and experimentally demonstrate a scheme to generate such hybrid entanglement by implementing a superposition of two distinct quantum operations. The generated states clearly show entanglement between the two different types of states. Our work opens the way to the generation of hybrid entanglement of greater size and the development of efficient quantum information processing using a new type of qubit.

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Figure 1: Scheme for generating hybrid entanglement of light.
Figure 2: Experimental generation of hybrid entanglement of light using temporal modes.
Figure 3: Experimental hybrid entanglement.
Figure 4: Experimental symmetric hybrid entanglement.

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Acknowledgements

A.Z., L.S.C., S.G. and M.B. acknowledge support from the European Union under the CHIST-ERA (European Coordinated Research on Long-term Challenges in Information and Communication Sciences & Technologies ERA-Net) project QSCALE (Quantum Technologies for Extending the Range of Quantum Communications) and from the Italian Ministry of Education, University and Research under the FIRB (Fondo per gli Investimenti della Ricerca di Base; contract no. RBFR10M3SB). H.J., M.K. and S.-W.L. were supported by the National Research Foundation of Korea (grant no. 2010-0018295) funded by the Ministry of Science, ICT and Future Planning of Korea. T.C.R. acknowledges support from the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology (project no. CE110001027).

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Contributions

H.J. and T.C.R. proposed the experiment and developed the theoretical models. M.K. and S.-W.L. performed theoretical analysis and numerical simulations. L.S.C. and S.G. ran the experiment and data analysis. A.Z. and M.B. proposed, planned and coordinated the experiment and data analysis. All authors discussed the results and implications of the experiment and contributed to writing the manuscript.

Corresponding authors

Correspondence to Hyunseok Jeong or Marco Bellini.

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The authors declare no competing financial interests.

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Jeong, H., Zavatta, A., Kang, M. et al. Generation of hybrid entanglement of light. Nature Photon 8, 564–569 (2014). https://doi.org/10.1038/nphoton.2014.136

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  • DOI: https://doi.org/10.1038/nphoton.2014.136

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