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arXiv · 1910.10377

Experimental orthogonalization of highly overlapping quantum states with single photons

Gaoyan Zhu·Orsolya Kalman·Kunkun Wang·Lei Xiao·Dengke Qu·Xiang Zhan·Zhihao Bian·Tamas Kiss·Peng Xue
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Abstract

We experimentally realize a nonlinear quantum protocol on single-photon qubits with linear optical elements and appropriate measurements. The quantum nonlinearity is induced by post-selecting the polarization qubit based on a measurement result obtained on the spatial degree of freedom of the single photon which plays the role of a second qubit. Initially, both qubits are prepared in the same quantum state and an appropriate two-qubit unitary transformation entangles them before the measurement on the spatial part. We analyze the result by quantum state tomography on the polarization degree of freedom. We then demonstrate the usefulness of the protocol for quantum state discrimination by iteratively applying it on either one of two slightly different quantum states which rapidly converge to different orthogonal states by the iterative dynamics. Our work opens the door to employ effective quantum nonlinear evolution for quantum information processing.

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Gaoyan Zhu, Orsolya Kalman, Kunkun Wang, Lei Xiao, Dengke Qu, Xiang Zhan, Zhihao Bian, Tamas Kiss, Peng Xue. 2019-10-23. Experimental orthogonalization of highly overlapping quantum states with single photons. https://doi.org/10.1103/physreva.100.052307

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