We present a method to measure the absolute surface resistance of conductive samples at a set of GHz frequencies with superconducting lead stripline resonators at temperatures 1- 6K. The stripline structure can easily be applied for bulk samples and allows direct calculation of the surface resistance without the requirement of additional calibration measurements or sample reference points. We further describe a correction method to reduce experimental background on high-Q resonance modes by exploiting TEM-properties of the external cabling. We then show applications of this method to the reference materials gold, tantalum, and tin, which include the anomalous skin effect and conventional superconductivity. Furthermore, we extract the complex optical conductivity for an all-lead stripline resonator to find a coherence peak and the superconducting gap of lead.
Absolute measurement of penetration depth of superconducting thin films using microwave stripline resonators
Tata Institute of Fundamental Research（塔塔基础研究所）；School of Physical Sciences, UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai（孟买大学物理科学学院，UM-DAE基础科学卓越中心）
Back-action evasion and squeezing of a mechanical resonator using a cavity detector
本文研究了利用参变耦合电磁腔对悬臂梁的量子测量。该方案最初是由于Braginsky等人[V.Braginsky，Y. I. Vorontsov和K. P.Thorne，Science 209，547（1980）]，允许悬臂运动的一个正交的反作用自由测量，并且因此有可能产生压缩状态。我们提出了一个完整的量子理论，这个系统，并推导出简单的条件时，量子限制的附加噪声可以被超越。我们还研究了测量的条件动力学，并讨论了如何这样的计划（与反馈耦合时）可以用来产生和检测压缩态的振荡器。我们的研究结果是相关的光学力学实验，并在量子力学实验中采用带状线谐振器耦合到机械谐振器。
Reflections on Quantum Reflectometry: Quantum and Tunneling capacitances as well as Sisyphus and Hermes resistances
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine（乌克兰国家科学院B.维尔金低温物理与工程研究所）；V. N. Karazin Kharkiv National University（哈尔科夫国立大学）；Department of Mathematics, Kyiv School of Economics（基辅经济学院数学系）；Quantum Motion（量子运动公司）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Quantum Computing Center, RIKEN（理研量子计算中心）；Physics Department, The University of Michigan（密歇根大学物理系）
Nanoelectromechanical resonators from high-T$_c$ superconducting crystals of Bi$_2$Sr$_2$Ca$_1$Cu$_2$O$_{8+δ}$
在这份报告中，我们提出了纳米机电谐振器的高T $_c$铜酸盐超导体Bi $_2$ Sr $_2$ Ca $_1$ Cu $_2$ O $_{8+δ}$薄剥离晶体制造。机械读出是通过将它们的运动电容耦合到用超导合金的共面波导微波腔来执行的。我们展示了机械频率可调谐性与外部直流偏置电压，和品质因数高达36600。我们的光谱和时域测量表明，在这些系统中的机械耗散是有限的电阻外层所产生的接触电阻。耗散的温度依赖性表明存在隧道态，进一步表明它们的固有性能可能与其他二维原子晶体（如石墨烯）一样好。
