1] National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK [2] Royal Holloway, University of London, Egham TW20 0EX, UK.
1] Laboratoire de Physique Theorique et Hautes Energies, CNRS UMR 7589, Universites Paris 6 et 7, 4 place Jussieu, Paris 75252, Cedex 05, France [2] Department of Physics and Astronomy, Rutgers The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA.
Nat Commun. 2014 Jun 17;5:4119. doi: 10.1038/ncomms5119.
The performance of a great variety of electronic devices--ranging from semiconductor transistors to superconducting qubits--is hampered by low-frequency noise with spectra proportional to 1/f. The ubiquity and negative impact of 1/f noise has motivated intensive research into its cause, and it is now believed to originate from a bath of fluctuating two-level defect states (TLSs) embedded in the material. This phenomenon is commonly described by the long-established standard tunnelling model (STM) of independent TLS. A key prediction of STM is that the noise should vanish at low temperatures. Here we report measurements on superconducting microresonators over previously unattainable, very long time scales that show an increase in 1/f noise at low temperatures and low microwave power, contrary to the STM. We propose a new generalised tunnelling model that includes significant interaction between multiple TLSs, which fully describes these observations, as well as recent studies of individual TLS lifetimes in superconducting qubits.
各种电子设备的性能——从半导体晶体管到超导量子位——都受到与 1/f 成正比的低频噪声的阻碍。1/f 噪声的普遍性和负面影响促使人们对其原因进行了深入研究，现在人们认为它起源于材料中嵌入的波动双能级缺陷态（TLS）浴。这种现象通常用独立 TLS 的成熟标准隧道模型（STM）来描述。STM 的一个关键预测是，噪声应在低温下消失。在这里，我们报告了在以前无法达到的非常长的时间尺度上对超导微谐振器的测量结果，这些结果显示在低温和低微波功率下，1/f 噪声增加，与 STM 相反。我们提出了一个新的广义隧道模型，其中包括多个 TLS 之间的重要相互作用，该模型完全描述了这些观察结果，以及最近对超导量子位中单个 TLS 寿命的研究。
