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Quantum oscillations in two coupled charge qubits

Yu. A. Pashkin·T. Yamamoto·O. Astafiev·Y. Nakamura·D. V. Averin·J. S. Tsai
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Abstract

Despite an apparent progress in implementing individual solid-state qubits, there have been no experimental reports so far on multi-bit gates required for building a real quantum computer. Here we report a new circuit comprising two coupled charge qubits. Using a pulse technique, we coherently mix quantum states and observe quantum oscillations whose spectrum reflects interaction between the qubits. Our results demonstrate the feasibility of coupling of multiple solid-state qubits and indicate the existence of entangled two-qubit states.

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Yu. A. Pashkin, T. Yamamoto, O. Astafiev, Y. Nakamura, D. V. Averin, J. S. Tsai. 2002-12-13. Quantum oscillations in two coupled charge qubits. https://doi.org/10.1038/nature01365

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