Strong-Field Effects in the Rabi Oscillations of the Superconducting Phase Qubit

Rabi oscillations have been observed in many superconducting devices, and represent prototypical logic operations for quantum bits (qubits) in a quantum computer. We use a three-level multiphoton analysis to understand the behavior of the superconducting phase qubit (current-biased Josephson junction) at high microwave drive power. Analytical and numerical results for the ac Stark shift, single-photon Rabi frequency, and two-photon Rabi frequency are compared to measurements made on a dc SQUID phase qubit with Nb/AlOx/Nb tunnel junctions. Good agreement is found between theory and experiment.

[1]  Roberto Ramos,et al.  Design for effective thermalization of junctions for quantum coherence , 2001 .

[2]  Matthias Steffen,et al.  Simultaneous State Measurement of Coupled Josephson Phase Qubits , 2005, Science.

[3]  J. Martinis,et al.  Rabi oscillations in a large Josephson-junction qubit. , 2002, Physical review letters.

[4]  E. Paspalakis,et al.  Influence of the asymmetry of the potential on the dynamics of a two-level superconducting quantum interference device qubit , 2005 .

[5]  Clarke,et al.  Energy-level quantization in the zero-voltage state of a current-biased Josephson junction. , 1985, Physical review letters.

[6]  Y. Pashkin,et al.  Rabi oscillations in a Josephson-junction charge two-level system. , 2001, Physical review letters.

[7]  F. Wellstood,et al.  Initializing the flux state of multiwell inductively isolated Josephson junction qubits , 2006 .

[8]  L Frunzio,et al.  ac Stark shift and dephasing of a superconducting qubit strongly coupled to a cavity field. , 2005, Physical review letters.

[9]  Roberto Ramos,et al.  Entangled Macroscopic Quantum States in Two Superconducting Qubits , 2003, Science.

[10]  M. Amin.  Rabi oscillations in systems with small anharmonicity , 2004, cond-mat/0407080.

[11]  K. Berggren,et al.  Mach-Zehnder Interferometry in a Strongly Driven Superconducting Qubit , 2005, Science.

[12]  A V Ustinov,et al.  Multiphoton transitions between energy levels in a current-biased Josephson tunnel junction. , 2003, Physical review letters.

[13]  Electromagnetically induced transparency in superconducting quantum circuits : Effects of decoherence, tunneling, and multilevel crosstalk , 2006, cond-mat/0604104.

[14]  Siyuan Han,et al.  Coherent Temporal Oscillations of Macroscopic Quantum States in a Josephson Junction , 2002, Science.

[15]  John M. Martinis,et al.  Accurate Control of Josephson Phase Qubits , 2003 .