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Simultaneous state measurement of coupled Josephson phase qubits



Robert McDermott, Raymond Simmonds, Matthias Steffen, Ken B. Cooper, Katarina Cicak, Kevin Osborn, Seongshik Oh, David P. Pappas, John M. Martinis


One of the many challenges of building a scalable quantum computer is singleshot measurement of all the quantum bits (qubits). We have used simultaneous single-shot measurement of coupled Josephson phase qubits to directly probe interaction of the qubits in the time domain. The concept of measurement crosstalk is introduced, and we show that its effects are minimized by careful adjustment of the timing of the measurements. We observe the antiphase oscillation of the two-qubit |01> and |10> states, consistent with quantum mechanical entanglement of these states,thereby opening the possibility for the full characterization of multi-qubit gates and elementary quantum algorithms.


entanglement, Josephson junction, quantum computing, qubits


Mcdermott, R. , Simmonds, R. , Steffen, M. , Cooper, K. , Cicak, K. , Osborn, K. , Oh, S. , Pappas, D. and Martinis, J. (2005), Simultaneous state measurement of coupled Josephson phase qubits, Science, [online], (Accessed June 15, 2024)


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Created February 24, 2005, Updated October 12, 2021