Simultaneous state measurement of coupled Josephson phase qubits

Published

February 25, 2005

Author(s)

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

Abstract

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.

Citation

Science

Volume

307

Pub Type

Journals

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Keywords

entanglement, Josephson junction, quantum computing, qubits

Citation

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], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=31860 (Accessed November 3, 2025)