The Spectrum in Qubit-Oscillator Systems in the Ultrastrong Coupling Regime
CHEN Qing-Hu1,2**, LI Lei3, LIU Tao3, WANG Ke-Lin4
1Center for Statistical and Theoretical Condensed Matter Physics, Zhejiang Normal University, Jinhua 321004 2Department of Physics, Zhejiang University, Hangzhou 310027 3School of Science, Southwest University of Science and Technology, Mianyang 621010 4Department of Modern Physics, University of Science and Technology of China, Hefei 230026
The Spectrum in Qubit-Oscillator Systems in the Ultrastrong Coupling Regime
CHEN Qing-Hu1,2**, LI Lei3, LIU Tao3, WANG Ke-Lin4
1Center for Statistical and Theoretical Condensed Matter Physics, Zhejiang Normal University, Jinhua 321004 2Department of Physics, Zhejiang University, Hangzhou 310027 3School of Science, Southwest University of Science and Technology, Mianyang 621010 4Department of Modern Physics, University of Science and Technology of China, Hefei 230026
摘要Recent measurement on an LC resonator magnetically coupled to a superconducting qubit [Phys. Rev. Lett. 105 (2010) 237001] shows that the system operates in the ultra-strong coupling regime and crosses the limit of validity for the rotating-wave approximation of the Jaynes–Cummings model. By using extended bosonic coherent states, we solve the Jaynes–Cummings model exactly without using the rotating-wave approximation. Our numerically exact results for the spectrum of the flux qubit coupled to the LC resonator are fully consistent with the experimental observations. The smallest Bloch–Siegert shift obtained is consistent with that observed in this experiment. In addition, the Bloch–Siegert shifts in arbitrary level transitions and for arbitrary coupling constants are predicted.
Abstract：Recent measurement on an LC resonator magnetically coupled to a superconducting qubit [Phys. Rev. Lett. 105 (2010) 237001] shows that the system operates in the ultra-strong coupling regime and crosses the limit of validity for the rotating-wave approximation of the Jaynes–Cummings model. By using extended bosonic coherent states, we solve the Jaynes–Cummings model exactly without using the rotating-wave approximation. Our numerically exact results for the spectrum of the flux qubit coupled to the LC resonator are fully consistent with the experimental observations. The smallest Bloch–Siegert shift obtained is consistent with that observed in this experiment. In addition, the Bloch–Siegert shifts in arbitrary level transitions and for arbitrary coupling constants are predicted.
(Quantum computation architectures and implementations)
引用本文:
CHEN Qing-Hu;**;LI Lei;LIU Tao;WANG Ke-Lin. The Spectrum in Qubit-Oscillator Systems in the Ultrastrong Coupling Regime[J]. 中国物理快报, 2012, 29(1): 14208-014208.
CHEN Qing-Hu, **, LI Lei, LIU Tao, WANG Ke-Lin. The Spectrum in Qubit-Oscillator Systems in the Ultrastrong Coupling Regime. Chin. Phys. Lett., 2012, 29(1): 14208-014208.
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