arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1609.06173cond-mat.mes-hall
收藏

约瑟夫森结中二能级系统的电子退相干

Electronic Decoherence of Two-Level Systems in a Josephson Junction

Alexander Bilmes, Sebastian Zanker, Andreas Heimes, Michael Marthaler, Gerd Schön, Georg Weiss, Alexey V. Ustinov, Jürgen Lisenfeld

摘要:

超导量子比特的灵敏度允许对$\mathrm{Al/AlO_x/Al}$约瑟夫森结的无序隧道势垒中存在的单个两能级系统进行光谱和相干测量。我们报告了Bogoliubov准粒子泄漏到绝缘$\mathrm{AlO_x}$屏障中的二能级系统退相干的实验证据。我们控制准粒子在结电极的密度,无论是通过样品的温度,或通过注入它们使用驱动到其电阻状态的片上dc-SQUID。通过观察共振微波脉冲作用下二能级系统的量子态的演化,测量了退相干率,发现退相干率随准粒子密度线性增加,与理论一致。这种与电子态的相互作用提供了一种噪声和退相干机制,这种机制与各种微制造器件(如量子比特、单电子晶体管和场效应晶体管)相关。所提出的实验还提供了一种可能性,以确定探测的两个级别的系统在隧道势垒的位置,提供线索的制造步骤中,他们出现。

英文摘要:

The sensitivity of superconducting qubits allows for spectroscopy and coherence measurements on individual two-level systems present in the disordered tunnel barrier of an $\mathrm{Al/AlO_x/Al}$ Josephson junction. We report experimental evidence for the decoherence of two-level systems by Bogoliubov quasiparticles leaking into the insulating $\mathrm{AlO_x}$ barrier. We control the density of quasiparticles in the junction electrodes either by the sample temperature or by injecting them using an on-chip dc-SQUID driven to its resistive state. The decoherence rates were measured by observing the two-level system's quantum state evolving under application of resonant microwave pulses and were found to increase linearly with quasiparticle density, in agreement with theory. This interaction with electronic states provides a noise and decoherence mechanism that is relevant for various microfabricated devices such as qubits, single-electron transistors, and field-effect transistors. The presented experiments also offer a possibility to determine the location of the probed two-level systems across the tunnel barrier, providing clues about the fabrication step in which they emerge.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑