Houck A A, Schreier J A, Johnson B R, Chow J M, Koch Jens, Gambetta J M, Schuster D I, Frunzio L, Devoret M H, Girvin S M, Schoelkopf R J
Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520, USA.
Phys Rev Lett. 2008 Aug 22;101(8):080502. doi: 10.1103/PhysRevLett.101.080502. Epub 2008 Aug 21.
We present a detailed characterization of coherence in seven transmon qubits in a circuit QED architecture. We find that spontaneous emission rates are strongly influenced by far off-resonant modes of the cavity and can be understood within a semiclassical circuit model. A careful analysis of the spontaneous qubit decay into a microwave transmission-line cavity can accurately predict the qubit lifetimes over 2 orders of magnitude in time and more than an octave in frequency. Coherence times T1 and T_{2};{*} of more than a microsecond are reproducibly demonstrated.
我们展示了在电路量子电动力学架构中七个传输子量子比特的相干性的详细表征。我们发现自发辐射率受到腔的远失谐模式的强烈影响，并且可以在半经典电路模型中得到理解。对自发量子比特衰变为微波传输线腔的仔细分析能够准确预测量子比特在时间上超过两个数量级以及在频率上超过一个倍频程的寿命。可重复地证明了相干时间T1和T2*超过一微秒。
