Low-temperature 1/f noise in microwave dielectric constant of amorphous dielectrics in Josephson qubits
Low-temperature 1/f noise in microwave dielectric constant of amorphous dielectrics in Josephson qubits
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DOI：
10.1103/physrevb.92.174201
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发表时间：
2015-11-16
影响因子：
3.7
通讯作者：
Schechter, Moshe
中科院分区：
文献类型：
--
作者：
Burin, Alexander L.;Matityahu, Shlomi;Schechter, Moshe
在考虑弱偶极子或弹性TLS相互作用的标准隧穿模型下，导出了非晶态薄膜由于隧道二能级系统(TLSS)引起的微波介电常数中低温1/f噪声的解析解。1/f的频率依赖是由TLS谱扩散引起的，其特征是宽度随时间对数增长。预测了具有普适TLSS的典型玻璃的噪声谱密度与温度和场的关系。对J·伯内特等人最近实验的令人满意的解释。[NAT。交警。5,4119(2014)]在铂帽Nb超导谐振器中，通过假设与普通玻璃相比较小的TLS密度而获得，这与这些样品中非常高的内部品质因数是一致的。
The analytical solution for the low-temperature 1/f noise in the microwave dielectric constant of amorphous films at frequency nu(0) similar to 5 GHz due to tunneling two-level systems (TLSs) is derived within the standard tunneling model including the weak dipolar or elastic TLS-TLS interactions. The 1/f frequency dependence is caused by TLS spectral diffusion characterized by the width growing logarithmically with time. Temperature and field dependencies are predicted for the noise spectral density in typical glasses with universal TLSs. The satisfactory interpretation of the recent experiment by J. Burnett et al. [Nat. Commun. 5, 4119 (2014)] in Pt-capped Nb superconducting resonators is attained by assuming a smaller density of TLSs compared to ordinary glasses, which is consistent with the very high internal quality factor in those samples.