Racah Institute of Physics, The Hebrew University of Jerusalem, Israel.
Phys Rev Lett. 2010 Oct 22;105(17):177001. doi: 10.1103/PhysRevLett.105.177001. Epub 2010 Oct 19.
We measure the lifetime (T₁) and coherence (T₂) of two-level defect states (TLSs) in the insulating barrier of a Josephson phase qubit and compare to the interaction strength between the two systems. We find for the average decay times a power-law dependence on the corresponding interaction strengths, whereas for the average coherence times we find an optimum at intermediate coupling strengths. We explain both the lifetime and the coherence results using the standard TLS model, including dipole radiation by phonons and anticorrelated dependence of the energy parameters on environmental fluctuations.
我们测量了约瑟夫森相位量子比特绝缘势垒中两能级缺陷态（TLS）的寿命（T₁）和相干性（T₂），并将其与两个系统之间的相互作用强度进行了比较。我们发现，对于平均衰减时间，其与相应的相互作用强度呈幂律关系，而对于平均相干时间，我们在中等耦合强度下发现了一个最佳值。我们使用标准的 TLS 模型解释了寿命和相干性结果，包括声子的偶极辐射和能量参数对环境涨落的相关依赖性。
