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arXiv · 0810.2635

Experimental asymmetric phase-covariant quantum cloning of polarization qubits

Jan Soubusta·Lucie Bartuskova·Antonin Cernoch·Miloslav Dusek·Jaromir Fiurasek
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Abstract

We report on two optical realizations of the $1 \to 2$ asymmetric phase-covariant cloning machines for polarization states of single photons. The experimental setups combine two-photon interference and tunable polarization filtering that enables us to control the asymmetry of the cloners. The first scheme involves a special unbalanced bulk beam splitter exhibiting different splitting ratios for vertical and horizontal polarizations, respectively. The second implemented scheme consists of a balanced fiber coupler where photon bunching occurs, followed by a free-space part with polarization filters. With this later approach we were able to demonstrate very high cloning fidelities which are above the universal cloning limit.

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Jan Soubusta, Lucie Bartuskova, Antonin Cernoch, Miloslav Dusek, Jaromir Fiurasek. 2008-10-15. Experimental asymmetric phase-covariant quantum cloning of polarization qubits. https://doi.org/10.1103/physreva.78.052323

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