Interqubit coupling mediated by a high-excitation-energy quantum object

被引:70
作者
Ashhab, S. [1 ,2 ,3 ]
Niskanen, A. O. [4 ,5 ]
Harrabi, K. [4 ]
Nakamura, Y. [1 ,4 ,6 ]
Picot, T. [7 ]
de Groot, P. C. [7 ]
Harmans, C. J. P. M. [7 ]
Mooij, J. E. [7 ]
Nori, Franco [1 ,2 ,3 ]
机构
[1] RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan
[2] Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA
[3] Univ Michigan, Michigan Ctr Theoret Phys, Ann Arbor, MI 48109 USA
[4] CREST JST, Kawaguchi, Saitama 3320012, Japan
[5] VTT Tech Res Ctr Finland, Espoo 02044, Finland
[6] NEC Nano Elect Res Labs, Tsukuba, Ibaraki 3058501, Japan
[7] Delft Univ Technol, Kavli Inst Nanosci, Quantum Transport Grp, NL-2628 CJ Delft, Netherlands
来源
PHYSICAL REVIEW B | 2008年 / 77卷 / 01期
基金
美国国家科学基金会;
关键词
D O I
10.1103/PhysRevB.77.014510
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We consider a system composed of two qubits and a high excitation energy quantum object used to mediate coupling between the qubits. We treat the entire system quantum mechanically and analyze the properties of the eigenvalues and eigenstates of the total Hamiltonian. After reproducing well-known results concerning the leading term in the mediated coupling, we obtain an expression for the residual coupling between the qubits in the off state. We also analyze the entanglement between the three objects, i.e., the two qubits and the coupler, in the eigenstates of the total Hamiltonian. Although we focus on the application of our results to the recently realized parametric-coupling scheme with two qubits, we also discuss extensions of our results to harmonic-oscillator couplers, couplers that are near resonance with the qubits and multiqubit systems. In particular, we find that certain errors that are absent for a two-qubit system arise when dealing with multiqubit systems.
引用
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页数:13
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